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1
Mohib, Kanishka. "Embryonic Stem Cell Extracts Possess Immune Modulatory Properties That Prevent Dendritic Cell Maturation and T Cell Activation." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/22794.
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Embryonic stem cells (ESC) possess immune privileged properties and have the capacity to modulate immune activation. ESCs can persist across allogeneic immunological barriers, prevent lymphocyte proliferation in mixed lymphocyte reaction (MLR) assays and can promote graft acceptance. However, clinical application of live ESC to treat immunological disorders is not feasible as live ESC can form teratoma in-vivo. In order to harness these properties of ESCs without adverse risk to patients, we hypothesized that ESC derived extracts may retain immune modulatory properties of whole cells and therefore could be used to abrogate allo-immune responses. We found addition of ESC-extracts from human lines H1 and H9, significantly prevented T cell proliferation in allogeneic MLRs. These results were confirmed using murine J1 ESC line. In-vitro studies showed human ESC EXT were able to modulate maturation of human monocyte derived dendritic cells (DC) by suppressing up-regulation of important co-stimulatory and maturation markers CD80, HLA-DR and CD83. In addition, DCs educated in the presence of human ESC extracts significantly lost their ability to stimulate purified allogeneic T cells compared to control extract treated DCs. We also determined that ESC extracts have an independent effect on T cells. ESC extracts prevented T cell proliferation in response to anti CD3/CD28 stimulation. In MLRs, ESC derived factors significantly down-regulated IL-2 and IFN-γ expression, while up-regulating TGF-β and Foxp3 expression. Furthermore, lymphocytes and purified T cells activated with anti-CD3/CD28, ConA and PMA proliferated poorly in the presence of ESC derived factors, while proliferation in response to ionomycin was not affected. Western blot analysis indicated that ESC derived factors prevented PKC-θ phosphorylation without influencing total PKC-θ levels. Moreover, IκB-α degradation was abrogated, confirming absence of PKC-θ activity. Therefore, ESC extracts have potent immune suppressive properties and may have clinical applications in ameliorating transplant rejection and autoimmune conditions.
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Holland, Kevin W. "Characterization and Application of Peanut Root Extracts." Diss., Virginia Tech, 2009. http://hdl.handle.net/10919/40264.
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Lipid oxidation is one of the leading causes of food quality degradation. Manufacturers typically add antioxidants or purge a productâ s package of oxygen to inhibit oxidation and the resulting off-flavors. Synthetic antioxidants (e.g. BHT, BHA) and some natural antioxidants (e.g. α-tocopherol) have found widespread use in this application. Unfortunately, the public views synthetic additives in a negative light and the current natural antioxidants have been unable to match the protection afforded by the synthetic antioxidants. The search for underutilized and natural antioxidants has led scientists to investigate many different plant-based extracts for use in food and in the treatment and prevention of disease. The objectives of this research were (1) to use ORAChromatography to identify peanut root extract fractions with high antioxidant capacity, (2) identification of compounds in peanut root extracts using HPLC and mass spectrometry, (3) test for the presence of aflatoxins in the extracts, (4) test peanut root extract in food model system for oxidation reduction capabilities, and (5) Testing peanut root extractâ s ability to decrease protein oxidation in cell culture.
Crude peanut root extracts have high antioxidant activities that do not vary by cultivar. The ORAC activities of the peanut root fractions separated by HPLC with a C18 column varied (600.3 â 6564.4 μM TE/g dry extract), as did the total phenolic contents (23.1 â 79.6 mg GAE/g dry extract). Peanut root fractions had aflatoxins contamination well above the 20 ppb limit. Peanut root extracts and the known antioxidants tested were found to have no significant effect in inhibiting oxidation of peanut paste or HBMEC. Peanut root extracts were not shown to have any positive effects, but further research is necessary to eliminate peanut root extracts as a possible food ingredient and health supplement.Ph. D.
3
Chan, Sze-yin. "The effects of ganoderma extracts on immune cell subsets." Click to view the E-thesis via HKUTO, 2009. http://sunzi.lib.hku.hk/hkuto/record/B43781494.
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Chan, Sze-yin, and 陳詩妍. "The effects of ganoderma extracts on immune cell subsets." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2009. http://hub.hku.hk/bib/B43781494.
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Auckland, Ian. "Quantitative Analysis of a Cell Cycle Checkpoint in Xenopus laevis Cell-Free Egg Extracts." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/34734.
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In somatic cells, checkpoint pathways trigger cell cycle arrest in response to
unreplicated or damaged DNA by inhibiting the activity of cyclin-dependent kinases
(Cdks). In the Xenopus laevis embryo, checkpoints are not operational until the
midblastula transition (MBT). Studies in cell-free egg extracts indicate that a threshold
concentration of nuclei, which approximates the MBT concentration, is required to elicit
a checkpoint. The checkpoint response to unreplicated DNA in the extract prevents
transition into mitosis by inhibiting Cdk1/cyclin B, causing an increase in the minimum
amount of cyclin B necessary to enter mitosis, termed the cyclin threshold. Once the
threshold of cyclin is maintained or exceeded, the system will proceed into mitosis after a
lag time. We have investigated the relationship between nuclear concentration and cell
cycle regulation in the extract. By precisely regulating the concentration of cyclin B and
nuclear content in extract samples, we have found 1) the concentration of nuclei affects
cyclin B thresholds and lag time of entry into mitosis, 2) elevated cyclin thresholds
caused by DNA replication blocks are further increased by increasing the concentration
of nuclei, and 3) double-stranded DNA breaks in the extract system do not affect cyclin
thresholds or lag time of entry into mitosis within the range of nuclear concentrations that
can be efficiently replicated. This data provides evidence of the importance of the
nucleocytoplasmic ratio in normal cell cycle progression and its importance for
checkpoint acquisition during early Xenopus laevis development.Master of Science
6
Palaty, Jan. "Oxidative coupling of dibenzylbutanolides catalyzed by plant cell culture extracts." Thesis, University of British Columbia, 1990. http://hdl.handle.net/2429/29710.
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This thesis aims to develop a new and inexpensive synthetic route to the anti-cancer drug etoposide (6) via 4'-demethylpodophyllotoxin (4) or 4'-demethylepipodophyllotoxin (5) involving the oxidative coupling of a dibenzylbutanolide catalyzed by a cell-free extract (CFE) from plant cell culture.
This step was studied in depth using the Catharanthus roseus CFE-catalyzed biotransformation of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3-hydroxy-4-methoxybenzyl)butanolide (58) to 1-(3,5-dimethoxy-4-hydroxyphenyl)-6-hydroxy-3-hydroxymethyl-7-methoxy-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (59) as a model. The optimum values of reaction pH, enzyme:substrate ratio and co-factonsubstrate ratio were determined. The butanolide 58 was synthesized by a route involving the Stobbe condensation of 3-benzyloxy-4-methoxybenzaldehyde with dimethylsuccinate to yield 2-(3-benzyloxy-4-methoxybenzylidene)butanedioic acid 1-methyl ester (69). Hydrogenation of 69 to 2-(3-benzyloxy-4-methoxybenzyl)butanedioic acid 1-methyl ester (70) followed by reductive lactonization afforded 3-(3-benzytoxy-4-methoxybenzyl)butanolide (71). Alkylation of 71 with 4-benzyloxy-a-bromo-3,5-dimethoxytoluene (72) gave frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3-benzyloxy-4-methoxybenzyl)butanolide (73) which was then converted to the butanolide 58 by catalytic hydrogenolysis.
In order to investigate the effect of different aromatic substituents on the oxidative coupling of butanolides, C. roseus CFE-catalyzed biotransformations of frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-methylenedioxybenzyl)butanolide (74) and frans-2-(3,5-dimethoxy-4-hydroxybenzyl)-3-(3,4-dihydroxy-a-hydroxybenzyl)butanolide (94) were also performed. The biotransformation of 74 gave 2-(3,5-dimethoxy-4-hydroxybenzylidene)-3-(3,4-methylenedioxybenzyl)butanoiide (76) as the sole isolated product. A pathway involving oxidative demethylatton is proposed to account for the balance of the unrecovered material.
The butanolide 94, a potential precursor to etoposide, was prepared from piperonal. The lithium anion of 1-bis(phenylthio)methyl-3,4-methylenedioxybenzene (97) and the bromide 72 were added consecutively to but-2-en-4-olide to afford frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxy-α,α-bis(phenylthio)benzyl)butanolide (96). A synthetic sequence involving the oxidation of 96 to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(3,4-methylenedioxybenzoyl)-butanolide (100), reduction to frans-2-(4-benzyloxy-3,5-dimethoxybenzyl)-3-(α-hydroxy-3,4-methylenedioxybenzyl)butanolide (109) and cleavage of the methylenedioxy and benzyl protecting groups gave the catechol 94. Unfortunately, the CFE-catalyzed oxidation of 94, following treatment with sodium borohydride, yielded 4-(3,4-dihydroxyphenyl)-5,7-dimethoxy-6-hydroxy-2-hydroxymethyl-1,2,3,4-tetrahydro-2-naphthoic acid γ lactone (103) as the sole isolated product.
[Formulas omitted]Science, Faculty of
Chemistry, Department of
Graduate
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Romanowski, Piotr. "Cell cycle regulation of DNA replication in Xenopus egg extracts." Thesis, University of Cambridge, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.624760.
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Johnson, Jodee Lee. "Effect of Black Raspberry Extracts on Colon Cancer Cell Proliferation." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244025041.
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Johnson, Jodee Lee. "Effect of back raspberry extracts on colon cancer cell proliferation." Columbus, Ohio : Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1244025041.
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Labbé, Etienne. "Temperature-modulation of protein phosphorylation in cell-free extracts of alfalfa." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1996. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ44093.pdf.
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Jackson, Simon James. "Cytotoxic activity of Kigelia pinnata against melanoma and other neoplastic cell lines." Thesis, King's College London (University of London), 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243809.
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Tan, Yi-Hsun. "Investigation of G1 Arrest Mechanisms Induced by Sanguisorba officinalis Extracts in B16F10 Cells." Kyoto University, 2019. http://hdl.handle.net/2433/245331.
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Dahlawi, Haytham. "Effect of pomegranate extracts on apoptosis and cell cycle in haematological malignancies." Thesis, Sheffield Hallam University, 2013. http://shura.shu.ac.uk/19527/.
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Leukaemia is a complex form of blood malignancy characterized by the uncontrolled proliferation of haematopoietic cells and progressive accumulation of these cells within the bone marrow (BM) and secondary lymphoid tissues. The exact cause of leukaemia remains unknown. Leukaemia is a major problem worldwide affecting many people each year. However, current treatment options still have several limitations not least, the cytotoxicity of these therapies to normal cells and the fact that certain chemotherapy agents may cause bone marrow toxicity and organ damage. Several epidemiological studies have shown that high intake of fruit and vegetables are associated with low incidence of a number of human cancers. Researchers suggest that pomegranates contain bioactive chemicals with potential for treatment and prevention of cancer. Pomegranate juice (PJ) have been shown to inhibit cellular proliferation and tumor growth and induce cell death via apoptosis in a number of cancer cell lines. However, to date, few studies have investigated the potential of PJ in the treatment of Leukaemia. Here, PJ significantly induced apoptosis in 8 leukaemia cell lines and non tumour control cells although the lymphoid and 2 myeloid cell lines were affected to a greater extent than non-tumour control cells and 2 of the myeloid cell lines. Furthermore, PJ induced cell cycle arrest. These results provide evidence that PJ contain bioactive compounds that could be used in the treatment of Leukaemia. Treatment of four Leukaemia cell lines with five fractions obtained from PJ by solid phase extraction demonstrated that only the acetonitrile fractions decreased adenosine triphosphate (ATP) levels in all Leukaemia cell lines. Acetonitrile fractions also significantly activated caspase-3 and induced nuclear morphology characteristic of apoptosis. S phase arrest was induced by acetonitrile fractions which matched S phase arrest seen previously following whole PJ treatments. The acetonitrile fractions contained higher phenol content than whole PJ whereas only low levels of phenols were seen in any other fraction. Liquid chromatography mass spectrometry (LC-MS)analysis demonstrated that acetonitrile fractions were enriched in ellagitannins, ellagic acid, and hydroxycinnamic acid derivatives but depleted in anthocyanins. The potential protective effect of a number of pure compounds that were either identified in the acetonitrile fraction of PJ were present in the other fractions of PJ or have been identified as PJ components in previous studies were studied on ATP levels in four human leukaemia cell lines. Among the 26 naturally occurring pomegranate compounds investigated, only seven compounds: delphinidin; cyanidin; pelargonidin; EGCG; gallic acid; ellagic acid; quercetin; and punicalagin induced 50% decrease in ATP levels in the studied leukaemia cell lines. To compare the chemoprotective properties of anthocyanins found in PJ and to understand the relationship between anthocyanin chemical structure and chemoprotective activity, the inhibition of cell proliferation and induction of apoptosis in leukaemia cell lines was measured. Anthocyanins activity was found to be dependent on the ortho-hydroxyphenyl structure and the most potent glycosidic form of the anthocyanins with proliferation and apoptosis effects seen in anthocyanins with greatest hydroxyl groups and least glycosidic form, namely delphinidin. Delphinidin induced apoptosis through intrinsic and extrinsic pathways. Suggesting that delphinidin may have potential for use as a chemotherapeutic agent against leukaemia. Furthermore, EGCG, gallic acid, quercetin, and punicalagin induced apoptosis and resulted in cell cycle arrest in the majority of the leukaemia cell lines. Together this study has shown that PJ is a rich source of bioactive compounds which could hold promise for treatment of leukaemia. The most promising compounds found within PJ were delphinidin, gallic acid, and punicalagin. Further investigation into these agents in the treatment and prevention of leukaemia are essential to develop these potential agents as future treatments.
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Sha, Wei. "Experimental evidnece for hysteresis in the cell cycles of Xenopus Laevis egg extracts." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/34575.
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In 1993, Novak and Tyson published a comprehensive mathematical model of the regulation of M-phase promoting factor (MPF) activity in Xenopus laevis eggs and egg extracts. Although this model was in agreement with existing and subsequent experimental data, fundamental predictions that the cell cycle is driven by a hysteresis loop have never been validated experimentally. The model's predictions of bifurcations that create and destroy MPF activity, indicative of hysteresis, were tested in this study. Prediction 1: The threshold concentration of cyclin B required to activate MPF is measurably higher than the threshold concentration required to inactivate MPF. The difference in thresholds implies that the MPF control system is hysteretic and bistable. To measure these thresholds, extracts in interphase or M-phase were supplemented with varying concentrations of non-degradable human cyclin B1 protein. MPF activity was determined by the morphology of sperm nuclei and by assays of histone H1 kinase activity. Consistent with the model, the activation threshold was determined to be 40 nM, which is two-fold higher than the inactivation threshold, 20 nM.
Prediction 2: For cyclin levels marginally above the activation threshold concentration of cyclin B, there is a dramatic "slowing-down" in the rate of MPF activation. Supra-threshold concentrations of nondegradable cyclin B1 were added to cycloheximide-treated CSF-released extracts, and samples taken at various time-points were analyzed for MPF activity. At 40 nM cyclin B1, just above the activation threshold, the lag time for MPF activation was 45 - 60 minutes; at 50 nM cyclin B1, the lag time was between 30 - 45 minutes; and at 60 nM or higher concentrations of cyclin B1, the lag time was 20 - 30 minutes, thus confirming the prediction of the Novak-Tyson model.
Prediction 3: DNA replication checkpoint increases the activation threshold concentration of cyclin B by increasing the hysteresis loop. Cycloheximide-treated, CSF-released extracts containing 1200 sperm nuclei/μl were treated with aphidicolin, then supplemented with varying concentrations of nondegradable cyclin B1. The activation threshold was 100 nM, 2.5 fold higher than in extracts lacking aphidicolin.
Conclusions: These studies confirm three predictions of the Novak-Tyson model and indicate that hysteresis underlies cell cycle control in Xenopus egg extracts. These experiments validate use of mathematical models to study complex biological control systems such as the eukayotic cell cycle.
Master of Science
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Odronitz, Florian. "Establishment and characterisation of an in vitro replication rystem with human cell extracts." [S.l. : s.n.], 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11482076.
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Adjerid, Nassiba. "The Dynamics of the Unreplicated DNA Checkpoint in Xenopus laevis Embryos and Extracts." Diss., Virginia Tech, 2008. http://hdl.handle.net/10919/26681.
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When unreplicated or damaged DNA is present, cell cycle checkpoint pathways cause cell cycle arrest by inhibiting cyclin-dependent kinases (Cdks). In Xenopus laevis, early embryonic development consists of twelve rapid cleavage cycles between DNA replication (S) and mitosis (M) without checkpoints or gap phases. However, checkpoints are engaged in Xenopus once the embryo reaches the midblastula transition (MBT). At this point, the embryo initiates transcription, acquires gap phases between S and M phases, and establishes a functional apoptotic program. During the cell cycle, there are two main checkpoints that regulate entrance into S and M phases. The focus of this study is the role of protein kinase Chk1 and the phosphatase Cdc25A in the DNA replication checkpoint. In the absence of active Chk1, Cdc25A activates cyclin dependent kinases (Cdks) allowing the cell to progress into S or M phase. Chk1 regulates cell cycle arrest in the presence of unreplicated DNA in somatic cells by phosphorylating Cdc25A and leading to its degradation. Chk1 is also transiently activated at the MBT in Xenopus laevis embryos, even when there is no block to DNA replication or damaged DNA. One goal of this work is to understand the developmental role and regulation of checkpoint signaling pathways due to its monitoring of DNA integrity within the cell.
Chk1 plays a critical but not fully understood role in cell cycle remodeling and early embryonic development. In order to understand the function and regulation of Chk1 in checkpoints, the features of the MBT that activate Chk1 must be identified. The activation of Chk1 by two time-dependent events in the cell cycle, the critical nuclear to cytoplasmic (N/C) ratio and the cyclin E/Cdk2 maternal timer are explored in this study. Embryos treated with aphidicolin, resulting in a halted replication fork and therefore a reduced DNA concentration, were tested for Chk1 activation and Cdc25A degradation. Chk1 and Cdc25A were observed to undergo activation and degradation, respectively, in embryos with a reduced DNA concentration. In addition, embryos were injected with Î 34Xic cyclin E/Cdk2 inhibitor, in order to disturb the maternal timer and tested for Chk1 activation and Cdc25A degradation. Both Chk1 and Cdc25A were unaffected by the disruption of the cyclin E/Cdk2 maternal time in the embryo. Therefore, the N/C ratio and the cyclin E/Cdk2 maternal timer do not affect Chk1 activation and therefore Cdc25A degradation.
Another means of characterizing the unreplicated DNA checkpoint is through the use of mathematical modeling of the checkpoint-signaling cascade of the cell cycle. Mathematical modeling is the translating of biological pathways into mathematical equations that can simulate interactions without performing laboratory experiments. The Novák-Tyson checkpoint model made important predictions of hysteresis and bistability in the frog egg checkpoint model, predictions that were later confirmed experimentally. The model was updated with additional interactions, such as those including Myt1, a second inhibitor kinase, and lamin proteins, which become phosphorylated at the onset of nuclear envelope breakdown (NEB) at entry into mitosis. Also, experimental data was fit into the model while maintaining hysteresis and bistability. Therefore, the unreplicated DNA checkpoint model was updated with new interactions and experimental data while still preserving previously identified dynamic characteristics of the system.
As described, Cdc25A regulation is dynamic in the embryo. The checkpoint original model represents the activity of Cdc25 phosphatase on the mitosis promoting factor (MPF) that leads the cell into mitosis. In the checkpoint model, Cdc25C is the phosphatase activating MPF. However, the model does not include Cdc25A, which is an integral part of the checkpoint-signaling pathway due to its role in activating the cyclin/Cdk complex allowing entry into S and possibly M phase. Experimental studies were performed in which Cdc25A levels were reduced in embryos and extracts using Cdc25A morpholinos. Embryos and extracts showed delayed cell cycle and mitotic entry, demonstrating the importance of Cdc25A plays in the cell cycle. Based upon experimental data, the mathematical model of the DNA replication checkpoint was expanded to include Cdc25A. The expanded model should more accurately demonstrate how checkpoints affect the core cell cycle machinery. Cdc25A was incorporated into the model by gathering experimental data and designing a signaling cascade, which was translated into differential equations. The updated model was then used to simulate the effect of synthesis and degradation rates of Cdc25A on the entry into mitosis dynamics. Therefore, using mathematical modeling and experimental design, we can further understand the role that Cdc25A plays in cell cycle progression during development.
Understanding the regulation of Chk1 activity at the MBT and the role of Cdc25A in checkpoint signaling will help us further characterize the dynamics of early embryonic development. The use of mathematical modeling and experimental tools both contribute to further our understanding of controls of the checkpoint signaling pathway and therefore leading us one step closer to truly being able to model a pathway and make predictions as to the behavior of the cell during early embryonic development.Ph. D.
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Baatjies, Lucinda. "In vitro cytotoxic effects of selected Nigerian medicinal plant extracts on cancer cell lines." Thesis, Nelson Mandela Metropolitan University, 2012. http://hdl.handle.net/10948/d1008191.
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Cancer is a disease that imposes a heavy burden on public health and poses a challenge to science. The World Health Organization estimates that 80 percent of people in developing countries of the world rely on traditional medicine for their primary health needs, and about 85 percent of traditional medicine involves the use of plant extracts. This is particularly true in Africa where a large percentage of the population depends upon medicinal plants for health care. Therefore, detailed screening and evaluation of bioactive substances for chemotherapeutic purposes of African plants are urgently warranted. Furthermore, this will serve to validate the efficacy and safety of African traditional medicine. The current study investigated the in vitro cytotoxic effects of 17 ethanolic extracts of the following 16 plants used in traditional anticancer medicine in Nigeria: Sapium ellipticum leaves, Sapium ellipticum stembark, Combretum paniculatum, Celosia trigyna, Pupalia lappacea, Justica extensa, Hedranthera barteri leaves, Alternanthera sessilis, Ethulia conyzoides leaves, Lannea nigritana stembark, Combretum zenkeri root, Combretum molle leaves, Adenanthera parvoniana, Lannea acida, Cyathula achyranthoides, Drymaria cordata, Cyathula prostrata, against HeLa cancer cells. Five of the most promising extracts (Sapium ellipticum leaves, Combretum paniculatum, Celosia trigyna, Drymaria cordata, Cyathula prostrata) were selected for further screening against HT29 and MCF-7 cancer cells. Of the five, the first two were investigated further based on their activities in the screening phase. The S. ellipticum leaf extract yielded IC50 values of 88.60 ± 0.03 and 93.03 ± 0.03 μg/ml against HeLa and MCF-7, respectively. The toxicity was also evaluated on normal cells and an IC50 of 77.66 μg/ml was obtained for peripheral blood mononuclear cells (PBMCs). The IC50 values for proliferating and confluent Chang liver cells were both >125 μg/ml. These results suggest that the extract may be selective for specific cell types. Bio-assay guided fractionation of the S. ellipticum ethanolic extract yielded two active fractions; chloroform and ethyl acetate. Two compounds isolated from the chloroform extract were screened against the three cancer cell lines and found to be inactive. Three compounds were isolated from the ethyl acetate fraction and revealed IC50 values < 62.5 and < 31 μg/ml against MCF-7. Unfortunately these two compounds soon lost activity before any further work could be done on them and work was continued with the crude extract.
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Mason, Rebecca Mary Aglaia. "The rejoining of non-homologous DNA double-strand breaks by mammalian cell free extracts." Thesis, University of Sussex, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336323.
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Chen, Chun, Peng Li, Ye Li, Guan Yao, and Jian-Hua Xu. "Antitumor effects and mechanisms of Ganoderma extracts and spores oil." SPANDIDOS PUBL LTD, 2016. http://hdl.handle.net/10150/622362.
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Ganoderma lucidum is a popular herbal medicine used in China to promote health. Modern studies have disclosed that the active ingredients of Ganoderma can exhibit several effects, including antitumor effects and immunomodulation. The present study evaluated the antitumor effects of self-prepared Ganoderma extracts and spores oil, and investigated the possible underlying mechanisms by observing the effects of the extracts and oil on topoisomerases and the cell cycle. The results showed that Ganoderma extracts and spores oil presented dose-dependent inhibitory effects on tumor cells. The half maximal inhibitory concentration (IC50) values of Ganoderma extracts on HL60, K562 and SGC-7901 cells for 24 h were 0.44, 0.39 and 0.90 mg/ml, respectively; for Ganoderma spores oil, the IC50 values were 1.13, 2.27 and 6.29 mg/ml, respectively. In the in vivo study, the inhibitory rates of Ganoderma extracts (4 g/kg/d, intragastrically) on S180 and H22 cells were 39.1 and 44.6%, respectively, and for Ganoderma spores oil (1.2 g/kg/d, intragastrically) the inhibitory rates were 30.9 and 44.9%, respectively. Ganoderma extracts and spores oil inhibited the activities of topoisomerase I and II. Ganoderma spores oil was shown block the cell cycle at the transition between the G1 and S phases and induce a marked decrease in cyclin D1 levels in K562 cells, with no significant change in cyclin E level. These results suggest that the Ganoderma extracts and spores oil possessed antitumor effects in the in vitro and in vivo studies. The antitumor mechanisms of the extracts and spores oil were associated with inhibitory effects on topoisomerase I and II activities, and for Ganoderma spores oil, the antitumor effects may also be associated with decreased cyclin D1 levels, thus inducing G1 arrest in the cell cycle.
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Silva, Inês Alexandra Marreiros. "Evaluation of chemotherapeutic potential of natural extracts using 3D models of colon cancer." Master's thesis, Faculdade de Ciências e Tecnologia, 2013. http://hdl.handle.net/10362/10982.
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Dissertation to obtain master degree in
BiotechnologyRecently there is a growing interest in cancer treatment through the use of natural compounds. In particular, phenolic compounds and monoterpenes found in fruits and vegetables are very attractive in the prevention and chemotherapy of various types of cancer. However, many promising compounds previously tested in in vitro cell models fail to demonstrate activity when evaluated in vivo. Therefore, there is an emerging need to develop more robust and reliable cellular models for pre-clinical evaluation of new chemotherapeutic agents. The main goal of this thesis was the evaluation of the chemotherapeutic potential of natural extracts, rich in bioactive compounds, using 3D models of colon cancer. For this purpose, a 3D model of human colorectal cancer cell line HT29 was developed. By culturing HT29 cells in a stirred culture system, it was possible to obtain 3D cellular spheroids with different size diameter during culture time. It was verified phenotypic changes within the spheroid along culture, such as formation of apoptotic core and altered expression of stem and epithelial markers in different spheroid areas, which are typical features of tumor progression. After an initial screening of the antiproliferative potential of 14 natural extracts performed in a 2D model of HT29 cells, the most promising samples were selected for further analysis in the 3D model. Cherry and orange extracts showed potential anticancer effect in HT29 aggregates through the inhibition of cell proliferation, induction of apoptosis and cell cycle arrest. A decrease on the bioactive effect was verified with the increase of aggregate diameter, probably due to limited diffusion. The anticancer activity was correlated with the phytochemical composition of natural extracts. For cherry extract, perillyl alcohol was the main bioactive compound identified whereas for orange extract, compounds like nobiletin, tangeretin and sinensetin were highlighted. Results of this thesis demonstrated that natural extracts of cherry and orange contain bioactive molecules with promising application on the development of new therapies for colon cancer treatment. The use of 3D cell models is a valuable tool for the study and evaluation of the effect of new chemotherapeutic compounds.
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Maharjan, Chandra Kumar. "Interaction of Na+/K+ ATPase with Bcl-2 Proteins: Isolated Enzyme vs Epithelial Cell Extracts." Wright State University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=wright1464692938.
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Borkowski, Tomasz. "Evaluation of plant extracts for anticancer potential in in vitro assays using colon cancer cell-lines." Thesis, University of Ulster, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.554236.
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Colorectal cancer is one of the most prevailing cancers worldwide with particularly high incidence and mortality rates in the Western countries. Compelling evidence indicates that diet is considered as an important etiological factor of colorectal cancer risk. Consumption of vegetables has been shown in numerous epidemiological, case-control and prospective studies to be inversely associated with the pathogenesis of several cancers including cancers of colon and rectum. Leguminous and cruciferous vegetables abundant in every day diet are a rich source of many bioactive compounds. Some of those phytochemicals such as glucosinolates and their derivatives, flavonoids - especially isoflavones and saponins have been demonstrated to be potent chemoprotective agents with an ability to inhibit carcinogenesis. Recently, sprouting seed of many plants has been popularized as a healthy and nutritious food plentiful in proteins, minerals, vitamins and a range of phytochemicals. The germination process results in significant increases in concentrations of particular compounds as compared to the mature plants and may contribute to enhanced anticancer activity of sprouts. The focus of this study was primarily to evaluate the anti-cancer effects of the extracts prepared from leguminous (alfalfa, red clover) and cruciferous (Raab broccoli, Daikon radish) sprouts on key stages of colon carcinogenesis, namely initiation, promotion and invasion using in vitro model systems. The shoots were investigated as a commercial product - BroccoShoots sprouts mixture which were processed following extraction methods to obtain crude juice, methanol and in vitro digested extracts to assess how changes in the chemical characteristics could affect the biological activity of the samples. BroccoShoots extract at the highest concentrations (100, 150, 200 ug/ml) inhibited growth of CaCo-2 cells. At non-toxic range of concentrations (0 - 50 ug/ml) BroccoShoots extracts reduced H202 induced DNA damage in CaCo-2 cells and significantly inhibited migration and invasion of the HT115 cell-line. These effects appeared to be stronger for the crude juice extracts than for the other two types of extracts. There were no evident changes in the epithelial integrity of CaCo-2 cells (measured as trans-epithelial electrical resistance) and in cell cycle progression (24 hours) after exposure to the extracts. Then individual plants were prepared as crude juice extracts to examine the extent to which particular species contributed to the overall activity of the mixture. It was found that anti-genotoxic, anti-proliferative, anti-migrative and anti-invasive effects observed for Daikon radish extracts were the highest among all individual sprouts. Further, Daikon radish extracts at non-toxic concentrations (35, 50 ug/ml) were shown to induce G2/M phase cell cycle arrest in CaCo-2 cells and significantly reduce cell proliferation (over 144 hours) due to cytostatic effects. Thus, it was postulated that anti- cancer effects exerted by BroccoShoots mixture were mainly mediated by activity of Daikon radish extracts. These results demonstrate that sprouts and notably Daikon radish sprouts were effective in inhibiting several stages of colon carcinogenesis in vitro. Also, hypothesis was proposed that lymphocytes could be used as a surrogate biomarker of colonic tissue in assessment of DNA hypermethylation status of genes involved in colon carcinogenesis and that supplementation with folate rich watercress could affect promoter methylation of these genes. However, no detectable levels in promoter methylation ofp16INK4a, MGMT, CDX-2 and C-Myc genes were found in lymphocytes from healthy volunteers. Moreover, there was no evidence that watercress consumption could change methylation status of investigated genes. This indicates that lymphocytes may not be a suitable marker for measurement of DNA hypermethylation in the selected genes.
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Richardson, Gaynor Rose-Marie. "Cell-free biosynthesis of abscisic acid (ABA) in extracts of flavedo from Citrus sinensis (L.) osbeck." Thesis, Rhodes University, 1996. http://hdl.handle.net/10962/d1003790.
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The biosynthetic origin of the plant growth regulator abscisic acid remains equivocal and almost nothing is known about the enzymes involved in this process. The present research programme describes the development of a cell-free system, capable of synthesizing abscisic acid and attempts to provide further information about the biochemistry and enzymology of this important biosynthetic pathway. Cell-free extracts were prepared either directly from the flavedo (crude) or from an acetone powder derived from flavedo, of mature coloured fruits of Citrus sinensis L. cv. Midknight and incubated with mevalonic acid, isopentenyl pyrophosphate, famesylpyrophosphate, geranylgeranyl pyrophosphate, ß-carotene and 1',4'-trans-abscisic acid diol. The neutral and acidic products formed were purified by thin-layer chromatography and high performance liquid chromatography, and quantified by high performance liquid chromatography, gas chromatography-electron capture and unequivocally identified by combined gas chromatography-mass spectrometry. Abscisic acid, 1',4'-trans-abscisic acid diol and phaseic acid were unequivocally identified as the major acidic products formed in this cell-free system. The acid fraction also contained xanthoxin acid. Labelled and unlabelled ß-carotene was converted into the neutral compounds xanthoxin and xanthoxin alcohol. In addition. high performance liquid chromatography-photodiode array analYSis of the oxy-carotenoid fraction revealed the complete spectrum of ß, ß-carotenoids induding zeaxanthin, antheraxanthin and violaxanthin with accumulation of an oxygenated carotenoid tentatively identified as 9- cis-violaxanthin. Identification of putative C₁₅ intermediates was achieved by either UV spectrophotometry and combined capillary gas chromatography-mass spectrometry or microchemical analYSis and co-chromatography. Refeeding studies using (±)-[2-¹⁴C]_ abscisic acid diol as substrate revealed that abscisic acid was not metabolized to abscisic acid diol, suggesting that it was/is produced as an intermediate rather than as a catabolite of ABA in this system. Stigmasterol, and to a lesser extent cholesterol reduced conversion of ß-carotene to abscisic acid but did not influence transformation of 1',4'-trans-abscisic acid diol to abscisic acid. AM01618 stimulated fonnation of abscisic acid and appeared to exert its effect at the level of conversion of 1' ,4'-trans-abscisic acid diol. Zeatin and the cytokinin analogue, ancymidol inhibited the biosynthesis of abscisic acid whereas dithiothreitol increased incorporation of label from ß-carotene into abscisic acid suggesting involvement of a cytochrome P450-type mixed function oxidase in this reaction sequence. Sodium dodecylsulphate polyacrylamide gel electrophoresis of the enzyme extract derived from Citrus flavedo revealed the presence of a 53 kD protein with peroxidase activity characteristic of a cytochrome P-450. Abscisic acid biosynthesizing activity was always greater in extracts from acetone powder and abscisic acid biosynthesis was enhanced in the presence of AMO 1618, NAD+, NADH, NADPH, MgCI₂ and Molybdate but was inhibited by FAD. Activity was further enhanced by the addition of (R,S)-abscisic acid as a cold-pool trap and by induding 0.1% w/v of either Tween 20 or Triton X 100 in the extraction buffer. When cis-ß-carotene was used as substrate, no abscisic acid was produced. Conversely when either all-trans-ß-carotene or a mixture of the two isomers was used, incorporation into abscisic acid occurred. Upoxygenase activity in cell-free extracts of Citrus flavedo increased with increasing protein concentration. As the ability of lipoxygenase to make xanthoxin from violaxanthin, had been reported, increased activity in the cell-free system implied that carotenoid deavage was being brought about by a non-haem oxygenase with lipoxygenase-like properties. Reports had implicated phoshorylation in the activation of many catalytic enzymes (Hanks et aI., 1985). Phosphorylation of the enzymes in this cell-free system proved unsuccessful. Further, it had been reported that in vitro phosphorylation of several membrane polypeptides and soluble polypeptides from com, had been promoted by the addition of Ca²₊ In this cell-free system Ca + did not have a stimulatory effect on protein phosphorylation. Dioxygenases generally occur as soluble enzymes, where they catalyse many oxygenation reactions in metabolic pathways. The addition of 2-oxo-glutarate, a requirement of most soluble oxidases, did not affect the activity of the cell-free system.
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Wu, Tai-Chia, and 吳岱珈. "Cell cycle arrest by Ganoderma tsugae extracts in human epidermoid A431 cell." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/45652394259118448926.
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碩士淡江大學
化學學系碩士班
95
The Epidermal Growth Factor Receptor (EGFR) and cyclin D1 are frequently amplified, overexpressed, or mutated in many cancers, including skin. We have previously demonstrated that the locally cultivated Ganoderma tsugae (G. tsugae, Lingzhi) extract possessing anti-cancer and anti-angiogenic properties in vitro and in vivo. The aim of the present work was to investigate the role of G. tsugae extracts in anti-cancer properties of EGFR-overexpressing human epidermoid carcinoma A431 cells. Using MTT assay, we demonstrated that G. tsugae extracts could inhibit the growth of A431 cells in a dose- and time-dependent manner. Western blotting analysis was used to investigate the mechanism of these effects. We demonstrated here a dose- and time-dependent down-regulation of expression of EGFR, cyclin D1 and CDK4 by G. tsugae extracts those correlate with the decrease in the proliferation of A431 cells. We also found that G. tsugae extracts-induced down-regulation of cyclin D1 was reversed by proteasome inhibitor, MG132, suggesting the role of ubiquitin-dependent proteasomal pathway. Furthermore, G. tsugae extracts treatment could cause the de-phosphorylation of constitutively active AKT and GSK3-beta. These finding suggest that G. tsugae extracts induces cell cycle arrest through proteasomal degration of cyclin D1 in EGFR-overexpressing human epidermoid carcinoma A431 cells might via the phosphatidylinositol 3-kinase/Akt-dependent pathway. Additionally, G. tsugae extracts could dramatically induce the expression of p21 while significantly inhibit the expression of the G1 phase cell cycle regulatory gene such as cyclin D1 and could suppress the expression of CDK4 protein. Taken together, our results suggest that proteasome-mediated down-regulation of cyclin D1 and up-regulation of CDK inhibitor might contribute to the antiproliferative effect of G. tsugae extracts against EGFR-overexpressing human epidermoid carcinoma.
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Chuang, Tingpin, and 莊鼎彬. "Antioxidative Activity and Cell Assay of Coleus blumei Extracts." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/04773146311540499795.
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碩士大葉大學
生物產業科技學系
99
Fresh leaves of Coleus blumei were first dried under various temperatures (40, 60, 80 and 100℃) and then were extracted using a hot water reflux. Also some fresh leaves of Coleus blumei were first sun-dried and then extracted by using a hot reflux with one solvent (water, methanol, ethanol, ethyl acetate or n-hexane). The purpose of this study is to examine the effect of extraction method on antioxidative activities of extracts. The assays of antioxidative activities included DPPH (α,α-diphenyl- β-picrylhydrazyl) radical scavenging ability, Fe2+ chelating ability, relative reducing power, superoxide anion scavenging ability, the inhibition of Fe/ascorbate-induced lipid peroxidation, and ABTS cation scavenging ability. These antioxidative activities of Coleus blumei extracts were measured and compared with those of butylated hydroxyanisole (BHA), ethylene diamine tetracetic acid (EDTA) or gallic acid. The component analysis and cell assay were also carried out for Coleus blumei extracts with the highest antioxidative activities. The results have showed that both of the extraction yield and the content of total phenols reached the highest when fresh leaves of Coleus blumei were extracted by hot water. The fresh leaves of Coleus blumei extracted by ethyl acetate had the highest content of total flavonoids, and however, most of total phenols and total flavonoids lost during drying. For the antioxidative activities, the extracts obtained by water and ethyl acetate had a higher DPPH radical scavenging ability (IC50＜0.01 mg/mL); the aqueous extract had the highest relative reducing power (IC50＝0.7 ± 0.00 mg/mL), the highest Fe2+ chelating ability (IC50＝0.13 ± 0.02 mg/mL), and the highest superoxide anion scavenging ability (IC50＝0.35 ± 0.00 mg/mL); the extract by ethyl acetate had the highest ABTS cation scavenging ability (IC50＜0.01 mg/mL); the extract by n-hexane had the highest inhibition ability of lipid peroxidation (IC50＝3.89 ± 0.14 mg/mL). In addition, the components of the extracts by water and ethyl acetate were analyzed by using an HPLC. The result showed that rosmarinic acid was the major component, and its content in the aqueous extract (232.09 mg/g) is higher than that in the ethyl acetate extract. In cell assays, the results show that the aqueous extract affected the HepG2 cell viability but didn’t affect the PC-12 cell viability. The aqueous extract showed the ability to protect PC-12 cells against hypoxia and H2O2-induced oxidative stress. In summary, the contents of total phenols and total flavonoids, and the antioxidant activities were highest for the extract from fresh leaves of Coleus blumei obtained by a hot water reflux. The extract could inhibit the growth of HepG2 cells and protect nerve cells against oxidative stress. The results obtained in this study are useful for future research and development of functional foods.
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Chien, Ling-Hui, and 簡伶卉. "The study of Toona sinensis leaf extracts-induced cell death in renal cell carcinoma." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/67168518600919374044.
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碩士高雄醫學大學
醫學研究所
101
Background： Renal-cell carcinoma is characterized by a lack of early-warning signs which results in a high proportion of patients with metastases and therapeutic inefficiency. Toona sinensis, a traditional herb, was reported to possess various biological functions such as anti-cancer, anti-oxidant, anti-diabetes, anti-angiogenesis, and anti-inflammation, etc. Aqueous leaf extracts of Toona sinensis (termed TSL-1) has been shown to inhibit cancerous cells proliferation including lung, ovarian, prostate, and premyelotic cells. In the present study, we examined the effects of TSL-1 on tumor regression by using in vitro RCC cell culture. Materials and methods： Cell viability was determined by morphological analysis, MTT assay and clonogenic assay. Cell migration was measured by transwell and wound healing method. The levels of mitochondrial membrane potential (examined by JC-1 and rhodamine 123), intracellular ROS accumulation (was using Carboxy–H2DCFDA), and early apoptosis (propidium iodide (PI)-annexin V double staining) were determined by flow cytometry. Apoptotic effects were confirmed by PI-annexin V assay and acridine orange/ethidium bromide (AO/EB) assay. Cell cycle effects were evaluated by flow cytometry. The related apoptotic caspase signaling molecules, and cell cycle dependent kinases and proteins were examind (CDKs) by immunoblotting analysis. Results： The anti-proliferative effect of TSL-1 on 786-O and A-498 cells was prominent after 24 h treatment. TSL-1 caused ccRCC cell death in a concentration- and time-dependent manner. PI-annexin V and AO/EB assays further confirmed that TSL-1 induced RCC cells apoptosis. Using flow cytometry, we further confirmed that TSL-1 arrested RCC cells at G0/G1 phase and increased cell numbers at subG1 phase. By immunoblot analysis, we further confirmed the cell cycle progress factors, such as cyclin D1, cyclin B, CDK2, and CDK4 were all down-regulated by TSL-1 treatment. On the other hand, TSL-1 stimulated ROS production and decreased the levels of mitochondria membrane potential in RCC cells which further activated the intrinsic apoptotic pathway. TSL-1 treatment induced cytochrome c leakage from mitochondria and reduced the expression of anti-apoptotic protein Bcl-2. Moreover, TSL-1 increased expressions of cleaved caspase 3, 7, 9, and cleaved PARP. TSL-1 is a multi-kinase drug for RCC cells. It blocked several cellular signaling pathway simultaneously, therefore, arrested the cell cycle and caused cell death, even inhibit the migration of cancer cells. The TSL-1-induced signaling pathways include JAK2/stat3, Akt/mTOR/HIF2??, MEK/ERK, NF-?羠, HSP70, and HSP90. In addition, lower concentration of TSL-1 blocked migration in both cell lines without cytotoxicity. Results showed that TSL-1 blocked MMP-9 expression and phosphorylation of NF-?羠. These results suggested that TSL-1 may reduce the invasion and migration in ccRCC cells. Summary： These results indicate that TSL-1 exerts cell cycle arrest and caspase-dependent cell death in RCC cells, supporting its potential usage in chemotherapeutics choice for kidney cancer.
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Wei, Xiang. "Mercury methylation in whole cells and cell extracts of sulfate-reducers and other bacteria." 2002. http://hdl.handle.net/1993/19760.
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Chiang, Chien-Chuan, and 江健銓. "Guava extracts inhibit cell proliferation and induce apoptosis in triple-negative breast cancer cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/4sxf66.
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Zeng-Wei and 王贈惟. "Pine extracts inhibit cell proliferation and promote apoptosis of human promyelocytic HL-60 cells." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/51879237558754473029.
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碩士中山醫學大學
免疫學研究所
98
In the ancient China’s books, [Shen Nong Ben Cao Jing] and [Bencao Gangmu], mention that plants such as pines, woods and grasses are the best source of drugs for lengthen human life and to be the health foods. People have all along been seeking to prolong life. Pinus morrisonicola Hayata is one of original coniferous species in Taiwan. Many previous studies indicate pine’s physiological activities and therapeutic effects, including as a remedy for carcinoma. But there are few reports regarding the biological effects of Pinus morrisonicola Hayata have been found so far. The objective of this study is to investigate the effects on inhibiting cell proliferation and promoting apoptosis of Pinus morrisonicola Hayata extracts and its active compounds. Results from this study indicated that Pinus morrisonicola Hayata extract, the partition of water phase and its compounds, pinocembrin, tiliroside, and chrysin, inhibiting cancer cell growth and promoting apoptosis. In addition, our data showed that Pinus morrisonicola Hayata extract at 500 μg/ml did not have significant cytotoxicity on peripheral blood mononuclear cells and zebrafish embryos. In conclusion, we have shown that Pinus morrisonicola Hayata extract exerts a significant effect on inhibition of cancer cell growth and induction of apoptosis in leukemia cancer cells mediated by cell cycle and apoptosis regulatory proteins. These data suggest that Pinus morrisonicola Hayata extract, as natural substances with powerful growth inhibition and induce-apoptosis effects on leukemia cells, will be a good candidate for chemoprevention or chemotherapeutic adjuvant in the future.
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Chen, Shi, and 陳曦. "Mechanistic Study of Deoxyinosine Excision Repair by Human Cell Extracts." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/74382226690889161544.
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Su, Ming-Jang, and 蘇明璋. "DNA Strand Specific Loop Repair by Escherichia coli Cell Extracts." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/83407467119324227879.
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碩士國立臺灣大學
醫事技術學系
85
Single-stranded loops may result from strand slippage during DNA replication. Such misaligned nucleotides if not corrected will cause expansion or deletion mutations. Expansion of trinucleotide repeats from a few to hundreds or even thousands of copies is associated with a number of heritable genetic diseases. Such expansion has been attributed to highly slippage nature of repetitive sequences during DNA transaction. However, little is known whether there is a repair mechanism responsible for such sing-stranded heterologies. In Escherichia coli, dam-directed mismatch repair system acts on DNA base pair mismatches. This system also corrects heteroduplex molecules containing small heterologies with high efficiency , though large heterologies are not repaired by suchsystem. An in vitro assay was designed to detect the correction of heteroduplexes with single-stranded loops. We prepared a series of M13mp18 derivative heteroduplex molecules containing1- to 8-、 10-、 22-、45- and 429-base loops and a site specific nick. An activity in E. coli cell extracts that repair those substrates was detected. The results showed that DNA heteroduplexes with single-stranded loops were repaired by a pathway that differs from MutHLS mismatch system. The results also showed that a pre-exisnick is a signal to direct repair to one strand and both nucleotide insertions and deletions can be repaired.
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Liang, Tzu-Ming, and 梁子明. "Studies of Scutellaria baicalensis Extracts Inhibiting Hepatic Endothelial Cell Activation." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/34804138261890511211.
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碩士國立陽明大學
傳統醫藥研究所
99
Liver fibrosis was the result of long-term liver damage and wound healing processes. If liver fibrosis continues to worsen, it will lead to cirrhosis or liver cancer. Therefore, if the course of chronic liver diseases could be effectively controlled, the development of cirrhosis or liver cancer could also be prevented. The aim of the study is to screen Chinese herbs against lipopolysaccharide (LPS)-activated rat liver endothelial cells (rLECs) and human umbilical vein endothelial cells (HUVECs). Moreover, the effects of conditioned medium from liver endothelial cells on hepatic stellate cells were studied. In the experiment, we isolated primary rLECs from Sprague-Dawley (SD) rat liver by liver perfusion. The purity of primary rLECs was evaluated by von Willebrand factor (vWF) immuno-fluorescence staining. The mRNA expression of primary rLECs and HUVECs were stimulated by LPS for in vitro study. The mRNA expressions of vascular endothelial growth factor (VEGF), VEGF receptor (VEGFR), transforming growth factor-β1 (TGF-β1), and monocyte chemoattractant protein-1 (MCP-1) genes were assessed by real-time PCR. The MCP-1 mRNA expression was selected as the common activation indicator in LPS-induced primary rLECs and HUVECs, and it was also used as a platform for screening Chinese herbs. The MCP-1 protein concentration of primary rLEC medium was detected by enzyme-linked immunosorbent assay kit (ELISA kit). The cytotoxicity of Chinese herbs was evaluated by MTT assay. Effects of rLEC conditioned medium on rat hepatic stellate cell (rHSC) migration was determined by wound healing assay. The results of highly vWf-positive staining showed that the purity of isolated rLECs was high. The MCP-1 mRNA expression showed similar trends in both endothelial cells induced by LPS at 6 h time-point. Crude ethanol extract (EtOH) and BuOH-soluble subfraction of S. baicalensis (25 μg/ml) significantly inhibited LPS-induced MCP-1 mRNA levels, without direct cytotoxity. Under bioactivity – guided fractionation, baicalein, baicalin, wogonin, and oroxylin-A were isolated from S. baicalensis. Results showed that baicalein and wogonin, but not baicalin and oroxylin-A, significantly inhibited MCP-1 mRNA levels in a concentration-dependent manner. The concentration of MCP-1 protein in primary rLEC medium was significantly decreased after baicalein (10 μg/ml) and wogonin (10 μg/ml) treatment by ELISA analysis. Primary rHSCs migration in rLEC-pre-conditioned medium was significantly decreased by pre-treatment of baicalein (10 μg/ml), but not baicalin (25 μg/ml), wogonin (10 μg/ml), and oroxylin-A (10 μg/ml). In conclusion, S. baicalensis significantly inhibited mRNA and protein expressions of MCP-1 in LPS-induced primary rat liver endothelial cells. Baicalein (10 μg/ml) attenuated rHSC migration in rLEC-pre-conditioned medium. These findings indicate that S. baicalensis might be a potential Chinese herb for anti-hepatic fibrosis.
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Chiang, Chien-Yueh, and 江芊玥. "Production of mouse primordial germ cell-like cells by Xenopus egg extracts in conditioned medium." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/unkgn6.
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博士國立中興大學
動物科學系所
107
The female germ cells develop until the generation of mature oocytes that receive male gametes, which ensures the continuity of life. There are many challenges in in vitro reconstitution of the female germ cell lineage in reproductive research. Embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) can be induced into primordial germ cell-like cells (PGCLCs) with the potential for regeneration of both genders of gametes. Even though the somatic or differentiated cells can be reprogrammed into iPSCs, they need to go through many stages of induction to reach oogenesis. In this study, we tested a different induction system that could reprogram differentiated cells (NIH-3T3) directly to early germ cells by using Xenopus egg extracts (XEE). The testing results of different culture systems to find a suitable one led to the ovary-conditioned medium with LIF (OL). The extracts-reprogrammed NIH-3T3 cells could be transformed into the early germ cell state, i.e. PGCLCs, when cultured in the conditioned medium. This medium had the potential to generate the germ cell lineage, and the possible reason was contained Bone Morphogenetic Proteins 4 (BMP4) and some molecules in the ovary, which supporting the reprogramming event. The OL induction system led extract-treated cells (ETCs) to form PGCLCs, whose oogenic ability was tested successfully by in vivo cell transplantation into oocyte-depleted mice. We conclude that Xenopus egg extracts contain molecules that can reprogram differentiated cells directly into the PGCLCs state when ETCs are cultured in OL medium. Furthermore, the PGCLCs are able to regenerate oocytes in sterilized mice. The germ cell lineage reprogramming event by Xenopus egg extract was demonstrated
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Hsu, Wei-Hsiang, and 許偉祥. "Study on the Effect of clam extracts in Hepatic stellate cell." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/35446285307773190969.
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碩士中原大學
生物科技研究所
97
In the western world, the major causes of liver fibrosis include alcohol, chronic hepatitis C infection and NASH (non-alcoholic steatohepatitis). This contrasts with Asia and Africa where chronic viral liver disease (hepatitis B and C) causes a massive burden of liver disease and cirrhosis. Furthermore, rates of hepatocellular carcinoma are high in these areas as cirrhosis predisposes to liver cancer. Liver fibrosis is characterized by excess deposition of collagens, resulting in an impairment of liver function and finally organ failure. Liver fibrosis is characterized by an activation of hepatic stellate cells (HSC). Quiescent HSCs become an activated phenotype which is characterized by alpha-smooth muscle actin (α-SMA) upregulation, increase in cell growth, and extracellular matrix secretion. The freshwater clam (Corbicula fluminea) is a widely-consumed shellfish and is used as a remedy for liver injury and anti-alcoholic toxicity in Asia. The purpose of this study would like to determine the roles of hepatoprotective effect of clam extracts. We have set up the intragastric infusion Tsukamoto-French rat model for approach in human liver fibrosis. According to our results of in vivo experiments, the clam extracts have ability to repair the injured by carbon tetrachloride in liver. In vitro assay, clam extracts significantly decreased activated HSC proliferation and induced an increase in the number of activated HSC in the G0/G1 phase by flow cytometry. In addition, clam extracts manifestly decreased α-SMA and collagen type I expression by Western blot assay in activated HSC. These results suggest clam extracts could inhibit activation of HSC.
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Hsiao-Yu and 洪筱喻. "Study of cytotoxicity of Wasabia japonica extracts on colon cancer cell." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/63041061859183595077.
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碩士中山醫學大學
生化暨生物科技研究所
98
Consumption of wasabi has many advantages such as increasing appetite, improving digestion and absorption and inhibiting bacteria and fungi in food. Previous research indicated that some components of wasabi can inhibit the proliferation of cancer cell. This study demonstrated the cytotoxic effect of wasabi (water extracts) on Coco-2 and COLO 205 cells. The results of DAPI and AVOs stains revealed that Caco-2 and COLO 205 cells both showed chromation condensation after wasabi treatment, and COLO 205 also formed AVOs, indicating that apoptosis was the major cell death mechanism caused by wasabi. Flow cytometry analysis demonstrated that low doses of wasabi (water extracts) induced growth arrest of COLO 205 cells at G2/M phase. High doses of wasabi, on the other hand, induced apoptosis of COLO 205 cells as evidenced by Annexin V and PI staining. Real time PCR analysis of the mRNA levels of apoptosis and autophagy related genes showed that both pathways were induced by wasabi extract in COLO 205 cells, and the expressions of some genes were dose-dependent to wasabi concentrations. Furthermore, a synergistic cytotoxic effect was observed when low dose of wasabi (100μg/ml) was combined with radiation. In nude mice experiment, wasabi alone did not suppress the growth of tumour. However, a combination of wasabi and radiotherapy delayed tumour growth significantly. Taken together, our studies demonstrate the anti-cancer function of wasabi in colorectal cancer and support the application wasabi as chemoprevention functional food.
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Hsieh-Hsun and 何協勳. "Mulberry extracts inhibit LDL oxidation, vascular smoothmuscle cell migration and proliferation." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/50297242974612340685.
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博士中山醫學大學
生化暨生物科技研究所
98
Atherosclerosis, a disease occurring in arteries, is one of the primary causes of heart diseases and is often the cause of death. Previous studies have shown that atherosclerosis is closely r elated to oxidative low-density lipoprotein dk3u3d. The oxidative modification hypothesis proposes that low density lipoprotein (LDL) oxidation and foam cell formation. Mulberry, a local edible fruit of Morus alba L., is used effectively in traditional medicines against fever, hepatic damage, rheumatic arthritis and hypertension. But few studies have investigated in detail the mechanism and effects of the mulberry fruit against atherosclerosis. In recent studies, the oxidative modification of LDL plays a key role in the pathogenesis of atherosclerosis. In this study, we evaluated two extracts, MWEs (mulberry water extracts) and MPEs (mulberry polyphenol-rich extracts ), which exhibited antioxidative ability in vitro. The antioxidative activity of the mulberry extracts on LDL oxidation was defined by relative electrophoretic mobility (REM), fragmentation of Apo B, thiobarbituric acid reaction substances (TBARS), and radical scavenging assay. Our results showed that low doses of MPEs were able to reduce the REM, Apo B fragmentation, and MDA formation in Cu2+-mediacted LDL oxidation model. MWEs and MPEs also had strong ability of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging. Further, we demonstrated that mulberry extracts could inhibit the foam cell formation and inhibit the expression of the macrophages scavenger receptors (CD36, SR-A) expression induced by oxLDL. Mulberry extracts showed strong potency for scavenging radical, and inhibiting the LDL oxidation and foam cell formation. We have demonstrated that the mulberry water extracts (MWEs) can effectively inhibit LDL oxidation and reduce the development of atherosclerosis in cholesterol-fed rabbits, suggesting that these extracts may prevent atherosclerosis by reducing early atherogenesis. The mechanisms by which mulberry extracts reduce the development of atherosclerosis are not yet fully understood. In these experiments, MWEs and MPEs could inhibit the migration and proliferation of ASMCs (A7r5 cells) by down regulation of Ras/PI3K/Akt pathway. MWEs and MPEs caused cell cycle arrest by inducing AMPK activation and attenuating of cyclin D/CDK and p53/Mdm2 complexes. At highly concentration of the extracts, MWEs and MPEs induced apoptosis by down regulation anti-apoptosis proteins strongly.In conclusion, we not only evaluated the strong antioxidative activity of the polyphenol extracts, but also observed MWEs and MPEs can inhibit proliferation and migration of ASMCs by decreace the transcription activity of NF-κB, FAK, small GTPase, and Ras protein, which were facilitated by integrin receptor. Therefore, it is suggested that the mulberry could be a healthy food to prevent individuals from atherosclerosis .
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Chiang-Hui, Wang, and 王薔惠. "Processing of heterologous sequences containing hairpin structure by human cell extracts." Thesis, 2001. http://ndltd.ncl.edu.tw/handle/16088883957051123037.
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碩士國立臺灣大學
醫事技術學研究所
89
Hairpin DNA structure can form from palindromes and from triplet (trinucleotide) repeats. The expansion of trinucleotide repeat sequences is associated with several neurodegenerative diseases. Palindromic loops may cause deletions or expansions of DNA sequences, which lead to genome instability. Processing of this structure is very important. To address this issue, we constructed a set of DNA heteroduplexes containing hairpin structure mispairs to characterize the in vitro activity in human cell extracts. Our results show that nuclear extracts from HeLa cell line is capable to correct hairpin mispairs within open circular DNA heteroduplexes. The reaction in this in vitro system, like human mismatch repair pathway, is strand-specific and highly biased to the incised DNA strand. Such nick-directed activity is absent in mismatch-repair-defective LoVo cell extracts. However, there is an activity of removing the hairpin structure on the hetereoduplex DNA substrates that is not directed by the nick. These in vitro activities are dependent on Mg2+, dNTPs, and ATP hydrolysis. The correction of these heteroduplexes in HeLa nuclear extracts was abolished by aphidicolin (inhibitor of polymerase α, d, ε). However, the reaction in LoVo nuclear extracts was sensitive to the presence of high concentrations of ddTTP (inhibitor of polymerase β). The above results indicate that in addition to mismatch repair, another pathway may also be involved in hairpin structure processing.
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Liang, Shu-Yang, and 梁書暘. "Terminalia chebula Extracts Inhibit Rotenone and Paraquat-induced PC12 Cell Death." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/20766534759875374973.
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碩士弘光科技大學
生物科技研究所
105
Thousands of years ago, Terminalia chebula was used to prevent neural disease. In India, because of its high medicinal value, it is used to treat various diseases. We use scientific methods to understand the pathway of T. chebula preventing Pa r k i n s on ’ s di s e a s e （PD）. Rat adrenal medulla pheochromocytoma（PC12 cell）is used to simulate neurons in nigrostriatal system. To simulate PD injure pathway, rotenone and paraquat are used as damage agents. PD is a degenerative disorder. The cause of PD has been traced to the degeneration of dopamine neurons within nigrostriatal system. There are many claims about the degeneration of dopamine neurons. The most respected one is the oxidative s t r e s s a nd α -synuclein dysfunction. In this research, we use T. chebula to find the possibility of prevention of PD. In this research, we use T. chebula to find the possibility of prevention of PD. After the determination of the effective constituent contents in T. chebula extracts and its antioxidant capacities, high performance liquid chromatography is used to characterize the standards. Then we use rotenone and paraquat to induce PC12 cell toxicity. The cell death was induced by rotenone and paraquat, and the protective effects of T. chebula extracts were evaluated. We assayed the decrease of the lactic dehydrogenase concentration, reactive oxygen species （ROS） generation, increase of intracellular calcium ion, decrease of α -synuclein and analyzing the expressions of caspase 3, Bcl-2 and Bax proteins. The results of T. chebula extracts are used to evaluate the possibility of prevention of PD. The results showed that T. chebula extracts had a significant inhibition to ROS generation and intracellular calcium ion concentration, and the decrease of pyknosis, apoptosis proteins and α-synuclein. In this study, there are several mechanisms can protect PC12 cells. The decrease of PC12 cell death is a result which has a reference value on further studies of prevention PD. Thus, T. chebula is the potential Chinese medicine.
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Lai, Hui-Chi, and 賴蕙琪. "Anticancer activity of the extracts of Sapindus saponaria against Non-small-cell lung carcinoma A549 cell line." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/88620457911188217564.
Full textAbstract:
碩士國立中興大學
生命科學院碩士在職專班
102
The fruit of Sapindus saponaria contains high concentration of saponin with antibacterial and anticancer effects. The aim of this study is to apply the various separations of methanol extract of S.saponaria on different kinds of cancer cells to examine their anticancer activity with MTT assay. The result showed that non-small cell lung carcinoma A549 cell is the most susceptible one for the cytotoxicity of the methanol extract of S.saponaria (ESS1), same as that of the previous study. The ESS1 was then fractioned into ethyl acetate layer (ESS2) and water layer (ESS3). The water fraction, ESS3, of ESS1 was hydrolyzed with KOH followed by the re-extraction of ethyl acetate to obtain ESS4. MTT assay was used again to determine the cytotoxicity on A549 cells with different kinds of extraction layers of S. saponaria. The data appeared that ESS2 showed the best result for cytotoxicity test. Through the flow cytometry analysis, ESS2 can arrest A549 cell growth at G1 phase of the cell cycle. The data of double staining experiment showed that ESS2 induced A549 cell to cell death with the necrosis pathway, same as that of ESS1. ESS1was combined formulation with the essential oil extract of Pelargonium capitatum, induced cell necrosis, or with the essential oil extract of Origanum vulgare, induced cell apoptosis, to A549 cells for synergic effect of treatments. After the MTT assay performance and through the Chou-Talalay equation to obtain CI values, both of the combined formulations observe no synergy effects.
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CHAO, WEI-LING, and 趙偉伶. "Inhibitory effects of O. grastissimum aqueous extracts on cell migration of the human colon adenocarcinoma cell line." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/v5ndhd.
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Huang, Chiung —Hseush, and 黃瓊雪. "Mulberry leaves extracts inhibit oxidation of LDL and smooth muscle cell proliferation." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/53797223635997585762.
Full textAbstract:
碩士中山醫學大學
生物化學研究所
92
Atherosclerosis is the leading cause of death in the cardiovascular disease. It is a systemic disease, a huge number of studies have revealed several risk factors involve in the progression of atherosclerosis. The oxidative modification hypothesis of atherosclerosis proposes that LDL oxidation and proliferation of vascular smooth muscle cell (VSMC) in the intima plays a causative role in early atherogenesis. If agents that can prevent LDL oxidation and proliferation of vascular smooth muscle cell, it could possibly attenuate the development of atherosclerosis. Flavonoids are a group of naturally occurring polyphenolic compounds ubiquitously found in plants, fruits and vegetables. It has shown potential antioxidative effects. In previous studies mulberry leaves extracts (MLEs) have many rich of flavonoids, possess antioxidative activity. In this study, we evaluated the effects of MLEs to inbibit oxidation of LDL and smooth muscle cell proliferation. The antioxidative activity of the MLEs on LDL oxidation was defined by Apo B fragmentation, relative electrophoretic mobility (REM) and thiobarbituric acid-relative substances (TBARS) assay . Our results showed that MLEs were able to inhibit the Apo B fragmentation, REM and TBARS assay in the Cu 2+ - mediated oxidativeLDL. It possessed the ability of DPPH radical scavenging. Taken together, MLEs showed a strong potency to inhibit the LDL oxidation induced by copper. In cultured cells experiments, have demonstrated that MLEs induced VSMCs apoptosis. The western blot have revealed that apoptotic-related protein (p-p53、Bax、Fas、FasL、cytochrome c、caspase 3,8,9、p-JNK、p-jun)were increased and anti-apoptotic-related protein (Bcl-2、Mcl-1、Bid、PI3K、Akt、NF-B、IAP) were reduced. In conclusion, mulberry leaves extracts (MLEs) possess ability to inhibit LDL oxidation and proliferation of vascular smooth muscle cell. Therefore, it is suggestive the mulberry leaves that may have multiple benefical effects on cardiovascular health, and the potential clinical application of these fascinating natural substance.
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Lee, Yi-Hsuan, and 李怡萱. "The application of Antrodia camphorata extracts used for maintaining stem cell pluripotency." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/13660456829511291505.
Full textAbstract:
碩士中國醫藥大學
基礎醫學研究所碩士班
101
Embryonic stem (ES) cells are pluripotent stem cells, that have the ability to differentiate into all types of cells. For this reason, ES cells have the potential to clinical application. Cultivation of the ES cells need leukemia inhibitory factor (LIF) to maintain ES cells self-renewal by activating Jak2/Stat3 signaling pathway. However, LIF is an expensive reagent. The goal in this study is to find out a traditional Chinese medicine extract which can replace LIF to maintain the pluripotency of ES cells. In our previous study, we found that Ethanol Extracts Antrodia Camphorata (EEAC) could increase the gene expression leves of Oct4 and Sox2, the genes that could maintain the stemness of stem cells. For this reason, AC has the potential to replace LIF in ES cells cultivation. ES cells were treated with different concentrations of EEAC and identified the stemness of ES cells by Alkaline phosphatease (AP) and immunofluorescent staining. We observed these cells expressed the characteristic of ES cells, including AP, Nanog, and SSEA1 at the concentration of 0.8 μg ml-1. Furthermore, the ES cells were passaged for six generation by the culture medium containing EEAC 0.8 μg ml-1, then used embryoid body formation to identify the pluripotency of ES cells. The results showed that the ES cells still could differentiate to the three germ layer including Tuj1, α-SMA, and Gata4. Finally, we wanted to know why EEAC could maintain the stem cell pluripotency and find the major pathway. By the data of western blot, Q-PCR and ELISA, EEAC activated Jak2/Stat3 pathway and increased the gene expression of related cytokines resulting in maintaining the ES cells self-renewal and pluripotency. In summary, we demonstrated that EEAC could maintain ES pluripotency by activing Jak2/Stat3 signaling pathway.
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Yi-Kuang, Chuang, and 莊以光. "Mechanistic Study of the Processing of Hairpin Structure by Human Cell Extracts." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/54206002440628473540.
Full textAbstract:
碩士國立臺灣大學
醫事技術學研究所
91
Trinucleotide repeats or palindromic sequences in DNA may form hairpin or stem-loop structures as a result of polymerase slippage during replication. These structures may consequently cause the expansion or deletion of DNA. If this happened within a specific gene, it is found to be associated with several human diseases. Prior studies indicated that the processing of palindromic loop in yeast and Chinese hamster ovary cells might be independent of mismatch repair system in vivo, however, the repair activity of palindromic loop in human cell is not yet reported. Thus, in our experiments, we characterized the in vitro activity in human nuclear extracts. A series of nicked and covalently closed circular forms of f1P heteroduplexes containing a hairpin mismatch were constructed and tested for repair in HeLa nuclear extracts. Our results show that in HeLa extracts, heteroduplexes were repaired effectively in a nick-directed way and repair efficiencies were higher when a mismatch is present within the hairpin structure. Similar activity was observed in MMR-deficient CCRF-CEM cell extracts, and revealed that the processing of hairpin structures is independent of the MMR. Reduced repair activity in complementary strand of close circular form heteroduplexes indicates that the nick can activate the process of hairpin repair. We also increased/decreased the length of the hairpin structure and found that the heteroduplex with the shortest hairpin had the highest repair efficiency. These repair activities are dependent on Mg2+, dNTPs, ATP hydrolysis and are abolished by aphidicolin (an inhibitor of polymerase α, d, ε). On the other hand, hairpin repair in human nuclear extracts was bi-directional and the distance from the 5’or 3’strand break to the heterology did not affect the repair activity. These results suggest that hairpin repair is different with MMR and the pathway of hairpin and loop repair may be similar.
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Oliveira, Daniela dos Santos. "Antigenotoxic and anticancer activities of plant extracts using different eukaryotic cell models." Master's thesis, 2017. http://hdl.handle.net/1822/45752.
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Dissertação de mestrado Biologia Molecular, Biotecnologia e Bioempreendedorismo em PlantasIn the last decades, the interest in medicinal plants has increased significantly owing to the antioxidant properties found in their natural extracts, which are responsible for many therapeutic effects. Therefore, there has been a great demand in discovering novel compounds, in order to develop new products (e.g. pharmaceuticals, cosmetics and dietary) characterized by high efficiency and low toxicity. Genotoxic stress might be induced by external and internal factors, causing serious damage since many cellular events, such as replication and transcription, depend on DNA integrity. The colonic epithelium is continuously exposed to a large diversity of dietary compounds, some of them potentially carcinogenic, that may affect DNA integrity (e.g. DNA oxidation and strand breaks) and alter cell genetic information, contributing to the development of colorectal cancer (CRC). Diets that are mainly based on polyphenols have been associated with CRC prevention. Medicinal plant extracts may also be rich in polyphenols and can be used to prevent DNA damage. In this work, eukaryotic cellular models were used to assess the antigenotoxic activity of medicinal plant extracts known for their strong antioxidant activity: Ginkgo biloba (GBE) and Dittrichia viscosa (DVE). The extracts demonstrated protective effect in co-incubation with the clastogenic agent camptothecin, in viability assays using the yeast Schizosaccharomyces pombe. This effect suggests an antigenotoxic role for the extracts, which may result from the stimulation of DNA repair through the homologous recombination pathway. Moreover, the antigenotoxic effect of GBE and its digested product (DGBE), obtained through in vitro simulation of the human digestion, was investigated in the human colorectal adenocarcinoma cell line HT-29 against oxidative stress, using the comet assay. The results suggested that pre-treatment with GBE or DGBE protected the DNA from deleterious effects induced by the oxidizing agent H2O2, probably due to stimulation of antioxidant defence mechanisms and DNA repair or through induction of mild stress in cells, which caused adaption to oxidative stress. The antigenotoxic effect of GBE and DGBE can be antioxidantmediated, which is in accordance with the results of the in vitro antioxidant assays of iron chelation and scavenging of the radicals 2,2-diphenyl-1-picrylhydrazyl and nitric oxide and studies of intracellular oxidation with the fluorochrome 2',7'-dichlorodihydrofluorescein diacetate by flow cytometry, in Sch. pombe. Thus, DVE and GBE demonstrated protective effect against clastogenic damage and GBE protected the DNA from oxidative effects, an effect retained after the digestion, suggesting that GBE could be used in the prevention of CRC.
Nas últimas décadas, o interesse em plantas medicinais tem aumentado significativamente devido às propriedades antioxidantes encontradas nos seus extratos naturais, as quais são responsáveis por muitos efeitos terapêuticos. Consequentemente, tem havido uma grande procura de novos compostos de modo a desenvolver novos produtos (ex: farmacêuticos, cosméticos e dietéticos) caraterizados por alta eficiência e baixa toxicidade. Stresse genotóxico pode ser induzido por fatores externos e internos, causando sérios danos visto que muitos eventos celulares, como a replicação e a transcrição, dependem da integridade do DNA. O cólon é continuamente exposto a uma grande diversidade de compostos dietéticos, alguns potencialmente carcinogénicos, que podem afetar a integridade do DNA (ex: oxidação do DNA e quebras de cadeia) e alterar a informação genética das células, contribuindo para o desenvolvimento de cancro colorretal (CRC). Dietas maioritariamente baseadas em polifenóis têm sido associadas à prevenção de CRC. Extratos de plantas medicinais podem também ser ricos em polifenóis e podem ser usados para prevenir danos no DNA. Neste trabalho, modelos celulares eucarióticos foram usados para avaliar a atividade antigenotóxica de extratos de plantas medicinais conhecidos pela sua forte atividade antioxidante: Ginkgo biloba (GBE) e Dittrichia viscosa (DVE). Os extratos demonstraram efeito protetor em co-incubação com o agente clastogénico camptotecina, em ensaios de viabilidade com a levedura Schizosaccharomyces pombe. Este efeito sugere um papel antigenotóxico para os extratos, o qual pode resultar da estimulação da reparação do DNA através da via de recombinação homóloga. Adicionalmente, o efeito antigenotóxico de GBE e do seu produto digerido (DGBE), obtido por simulação da digestão humana in vitro, foi investigado na linha celular humana de adenocarcinoma colorretal HT-29 contra stresse oxidativo, usando o ensaio cometa. Os resultados sugeriram que pré-tratamento com GBE ou DGBE protegeu o DNA de efeitos oxidantes induzidos por H2O2, provavelmente devido à estimulação dos mecanismos de defesa antioxidante e reparação de DNA ou através da indução de stresse moderado nas células, o qual pode causar adaptação ao stresse oxidativo. O efeito antigenotóxico de GBE e DGBE pode ser mediado pela atividade antioxidante, o que está de acordo com os resultados dos ensaios antioxidantes in vitro de quelação de ferro e scavenging dos radicais 2,2- difenil-1-picrilhidrazil e óxido nítrico e estudos de oxidação intracelular com o fluorocromo 2',7'- diclorodihidrofluoresceína diacetato por citometria de fluxo, em Sch. pombe. Assim, DVE e GBE demonstraram efeito protetor contra dano clastogénico e GBE protegeu o DNA de danos oxidativos, um efeito retido após a digestão, sugerindo que GBE poderia ser usado na prevenção de CRC.
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Pereira, Lucília Celina Silva Pebre. "Exploring the chemotherapeutic potential of Brassicaceae extracts in colorectal cancer cell spheroids." Master's thesis, 2016. http://hdl.handle.net/10362/19554.
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Colorectal cancer is the third most common cause of mortality worldwide. Given the growth and increasing life expectancy of the world’s population, as well as the acquisition of unhealthy lifestyle habits, the global burden of colorectal cancer is estimated to increase in the next years. Despite the efforts made so far, its treatment is still very challenging due to cancer recurrence usually associated with prevalence of cancer stem cells (CSCs) after treatment. Hence, it is imperative to seek new therapeutic strategies that target colorectal CSCs.
Epidemiological data have reported a positive correlation between cruciferous vegetables intake and decreased risk of colorectal cancer. Their chemo-preventive effect is mainly due to their high content in glucosinolates, the precursors of isothiocyanates (ITCs) that are known to modulate and target several aspects of carcinogenesis.
Hence, by recurring to a green and sustainable high pressure extraction process to recover ITCs from cruciferous vegetables, namely watercress and broccoli, we intended to explore the anticancer mechanisms of Brassicaceae vegetables and respective ITCs in a tri-dimensional (3D) cell model of colorectal cancer (i.e. in cell spheroids), since this approach resembles best with the tumor microenvironment in comparison with the conventional two-dimensional (2D) cells models. Our results revealed that Brassicaceae extracts and ITCs have the potential to prevent cell proliferation and chemo-resistance, to induce apoptosis, and to target colorectal CSC population and its self-renewal ability. Therefore, our research provides new insights on colorectal cancer therapy using nutraceuticals derived from cruciferous vegetables.
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Chang, Lien-Yu, and 張蓮鈺. "Effects of areca nut extracts on the regulation of immune cell functions." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/26801277966897790530.
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博士國立陽明大學
臨床牙醫學研究所
96
Areca chewing, a popular habit in Taiwan and many Asian countries, is closely related to oral diseases such as oral carcinogenesis and periodontitis. Areca chewing might cause mucosa microtrauma and provide access of areca ingredients to local tissue including structural cells, inflammatory cell infiltrate and peripheral blood, hence increases oral inflammatory/immune responses. Inflammation, the hallmark of the innate immune response, orchestrates local environment and disease progression. Various inflammatory mediators present in diseased tissues are known to underpin tissue damage and modulate the immune responses. The purpose of this study was to investigate the effects of ripe areca nut extracts (rANE) and tender areca nut extracts (tANE) on the expression of inflammatory cytokines, tumor necrosis factor-�� (TNF-��), interleukine (IL)-1��, IL-1��, IL-6, and IL-8, the lipid mediator prostaglandin E2 (PGE2) and the inducible enzyme cyclooxygenase-2 (COX-2) in human peripheral blood mononuclear cells (PBMC) as measured by the enzyme-linked immunosorbent assay (or enzyme immunoassay) and the reverse transcription-polymerase chain reaction. The levels of intracellular reactive oxygen species (ROS) were examined using a fluorometric assay. Effects of antioxidants on expression of inflammatory mediators and intracellular ROS were also studied. The results demonstrated that both rANE and tANE significantly enhanced the production of inflammatory molecules examined in PBMC by a dose- and time- dependent manner. The transcripts of TNF-��, IL-1��, IL-6 and COX-2 were also increased by rANE and tANE. Both antioxidants, curcumin and PDTC, reduced the expression of various inflammatory mediators in PBMC enhanced by rANE and tANE. The intracellular ROS induced by rANE and tANE were also reduced by curcumin. Effects of rANE and tANE on immune cell functions were similar, however, several discrepancies such as opposite effects of PDTC on expression of TNF-�� implicated that the signaling impacts may be varied among rANE and tANE treatments. In conclusion, areca chewing may create a sustained chronic inflammatory milieu with persistent oxidative stress in oral cavity via induction of intracellular ROS and a variety of inflammatory mediators by immune cells. Markedly inhibitory effects of antioxidants on ANE-induced inflammatory molecule expression implicated that oxidative stress is crucial in this areca-associated immune modulation. However, the clinical relevance of these findings remains to be determined.
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Huang, Ii-Ming, and 黃逸民. "Ganoderma tsugae methanol extracts could induce apoptosis in human epidermoid A431 cell." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/38464425201169828670.
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碩士淡江大學
化學學系碩士班
95
Ganoderma (Lingzhi), an oriental fungus, has been widely used as a medical drug or health-promotion product in Asian countries. Lingzhi have been demonstrated to possess immunomodulatory and anti-tumor activities. On the other hand, the Epidermal Growth Factor Receptor (EGFR) is frequently amplified, overexpressed, or mutated in many cancers, including skin, colon, lung, breast, head and neck cancer. We have investigated, at high doses (>1 mg/ml), the methanol extracts from the Ganoderma tsugae (G. tsugae) could be cytotoxic through induction of apoptosis. In the present study, we examined the effect of G. tsugae extract on apoptotic biochemical events in EGFR-overexpressing human epidermoid carcinoma A431 cells. G. tsugae extracts treatment could down-regulate the EGFR protein level and cause the de-phosphorylation/inactivation of constitutively active AKT. This data suggest that G. tsugae extracts could induce apoptosis might through downregulation of EGFR in A431 cells. Furthermore, G. tsugae extracts also could induce release of cytochrome c accompanied by activation of caspase-3 and PARP cleavage. Finally, treatment of A431 cells with G. tsugae extracts could down-regulate the expression of inhibitors of apoptosis protein, such as Bcl-2 and Bcl-xL. Taken together, our finding suggest that G. tsugae extracts could down-regulate EGFR protein level and its downstream signaling pathway in EGFR-overexpressing human epidermoid carcinoma A431 cells leading to the inhibition of proliferationand induction of caspase-dependent apoptosis.
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Chang, Li-Ying, and 張麗穎. "Induction of Apoptosis in Human Hepatoma HepG2 Cell Line by Dandelion Extracts." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/53740925773196535039.
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碩士亞洲大學
保健營養生技學系碩士班
96
Dandelions have long been used as the folk medicine for their choleretic,diuretic and antirheumatic properties and are available today in market for a variety of health benefits. The anti-inflammatory activity of dandelion extracts has been confirmed in animal studies and dandelion flower fractions have been shown to possess both antioxidantive and cytotoxic properties.Considering the long history of the dandelion as the herb medicine, relatively little is known about their efficacy against liver cancer. In the present study,we examined the antioxidantive capabilities and cytotoxicity of aqueous and 70% ethanolic extracts（AED and EED, respectively）of dandelion as well as apoptosis induction and mechanism in human hepatoma HepG2 cell line. Both AED and EED displayed similar patterns on DPPH scavenging activity and reducing power, while only AED exhibited ferrous ion chelating ability. The contents of total phenolic compounds and flavonoids were higher in AED as compared with those of EED. By trypan blue assay, we demonstrated that dandelion extracts reduced viability of HepG2 cells via a dose- and time-dependent manner. Furthermore, apoptotic features such as cell shrinkage, DNA fragmentation, Sub-G1 accumulation, increased fluorescence intensities of annexin V/propidium iodide staining and TUNEL assay were observed in dandelion extracts-treated HepG2 cells. During the process of apoptosis induction, we noticed that administration of dandelion extracts resulted in the activation of caspase-8 protein and alteration of caspase-8 and caspase-3 mRNA expressions. Taking together, our results show that dandelion extracts presented both antioxidantive and cytotoxic effects. The dandelion extracts-induced suppression of cell viability of HepG2 may in part be attributed to their phytochemical contents and as an effective inducer of apoptosis as well.
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Tsai, Chia-Ju, and 蔡佳儒. "The inhibition activity of Chinese herbs extracts on UVB induced cell death." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/59400648496109337422.
Full textAbstract:
碩士嘉南藥理科技大學
生物科技系暨研究所
91
The object of this research is use microwave to extract Chinese herbs, and investigate activity inhibition of Chinese herbs extraction on UVB induced cell death. B16 melanoma cell is introduced for UVB expose with several Chinese herbs extractions, such as licorice root, mulberry, white mulberry, ginkgo, angelica root, Paeony root bark. Especially “licorice root” shows better inhibition result. Thus, we chose the follow four major compounds of licorice root to do the next experiment, such as Glycyrrhizic acid (GZA), 18? Glycyrrhetinic acid, 18β-Glycyrrhetinic acid (GTA), dibenzoylmethane(DBM). Except DBM, the other shows over 50~70% cell viability in different concentrations. In additional, using gel electrophoresis to observe the change of DNA with Chinese herbs extraction. And DAPI is also observed fluorescence due to change of nuclei. Another side, to investigate relation between cell activity and protein synthesize, we use cycloheximide to analysis, which is a kind of protein neosynthesis inhibitor. From the experiment result, we know that cell death inhibition of Chinese herbs is relative to protein synthesize. Besides, for study inhibition of Chinese herbs extraction whether is relative to scavenge of free radical. Using L-(+)-Ascorbic acid, (-)-epigallocatechin gallate (EGCG) with damaged cell by UVB. Both of them are no influence to the cell, so infer that inhibition is not relative to scavenge of free radical. At the final, apply Chinese herbs with sunscreen (SPF4), within Chinese herbs extraction will gets more protection result than without. This result could do advanced application on therapy of skin, and make UVB damaged skin get improve.
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Chen, Chun-Hao, and 陳鈞浩. "Effect of Cinnamomum osmophloeum Kanehira Extracts on Cell Proliferation and Melanin Formation." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/01569144676121298784.
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碩士大葉大學
生物產業科技學系
100
Melanin is the major pigment for the color of human skin. It is secreted by melanocytes in the basal layer of the epidermis. Melanin may be overproduced on chronic sun exposure, melasma, or other hyperpigmentation diseases.. Tyrosinase, a copper- containing monooxygenase, is the key enzyme that catalyzes of synthesis melanin in melanocytes. Cinnamomum zeylanicum has been reported to inhibit the activity of tyrosinase. Cinnamomum osmophloeum Kanehira, a Taiwan endemic plant, is known as antioxidant. The potential in skincare of C. osmophloeum Kanehira extracts is studied. The experiment applied three sources with different chemical types, those are G2, P3 and TFA that respresent cinnamaldehyde- cinnamylacetate, mixed and uncharacterized chemical structure respectively. Adding 20ng/mL of ethanol extracts to B16-F10 cell that did not cause growth retardation or cell death, the G2 and the P3 extracts can suppress 24~25% tyrosinase activity and reduced melanin accumulation in the B16-F10 cell. At the same time, the mRNA for tyrosinase was down-regulated. Administration cinnamon extracts to cell before or after exposure to UV, in both conditions more cell survived from the UV damage. In conclusion, all the three cinnamon extracts benefit cells in terms of reducing melanin accumulation and reducing UV caused cell death. This seems imply that cinnamon is a good candidate for skin care in protection and melanin inhibition.