Zeitschriftenartikel: „QUERCETIN ANALOGUES“

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Otieno, Filex, und Richard Kagia. „Virtual screening for chemical analogues similar to phytochemicals that inhibit aldose reductase in the development of diabetic microvascular complications“. F1000Research 12 (21.03.2023): 314. http://dx.doi.org/10.12688/f1000research.129663.1.

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Background: The polyol pathway contributes to the development of diabetic complications but can be inhibited by plant phytochemicals. This study aimed at assessing analogs of specific flavonoids that delay onset of microvascular complications with better pharmacokinetic and toxicology profiles. Methods: An in silico study design was employed. The phytochemicals luteolin and quercetin were selected. Analogs were obtained from ZINC database and prepared using Avogadro software. Docking analysis was done using AutoDock Vina embedded in Chimera. Ligand enzyme interaction was carried out using Biovia Discovery studio. Pharmacokinetic and toxicological profiling was carried out using SWISSADME and protox server. A total of 40 analogues were analyzed. Sulindac was used as the comparator besides original phytochemicals. Results: Docking analysis showed both luteolin and quercetin (-9.7) had a slightly stronger affinity for inhibiting aldose reductase compared with sulindac (-9.6). Eight analogues of luteolin and 14 analogues of quercetin showed stronger affinity with the highest registered at -10.6. Both luteolin and quercetin did not violate the Lipinski rule, had high GI absorption, did not cross the blood brain barrier nor were p-glycoprotein substrates, and inhibited CYP1A2, CYP2D6 and CYP3A4. The LD50 of luteolin (3,919 mg/kg) was high indicating excellent safety profile. Quercetin had a low LD50 (159 mg/kg). All 22 analogues exhibited similar pharmacokinetic profiles to their respective phytochemical. However, they did differ in terms of docking strength and toxicology analysis. Six out of the eight luteolin analogues had LD50=3,919 mg/kg, while the remaining had LD50=159 mg/kg. Five quercetin analogues had LD50 of 159 mg/kg, another five had LD50=3,919 mg/kg and the rest had LD50=4,000 mg/kg, while the other two had a LD50 of 5,000 mg/kg. Conclusions: In conclusion, six ZINC compounds similar to luteolin and nine similar to quercetin had stronger binding affinity for aldose reductase and superior toxicological profile compared to parent phytochemicals.

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Pardo, Antonelle, Thomas Josse, Laetitia Mespouille, Bertrand Blankert, Philippe Dubois und Pierre Duez. „Synthesis of Quercetin-imprinted Polymer Spherical Particles with Improved Ability to Capture Quercetin Analogues“. Phytochemical Analysis 28, Nr. 4 (26.01.2017): 289–96. http://dx.doi.org/10.1002/pca.2674.

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Biler, Michal, David Biedermann, Kateřina Valentová, Vladimír Křen und Martin Kubala. „Quercetin and its analogues: optical and acido–basic properties“. Phys. Chem. Chem. Phys. 19, Nr. 39 (2017): 26870–79. http://dx.doi.org/10.1039/c7cp03845c.

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Imai, Kohei, Ikuo Nakanishi, Kei Ohkubo, Yusuke Ohba, Takuya Arai, Mirei Mizuno, Shunichi Fukuzumi, Ken-ichiro Matsumoto und Kiyoshi Fukuhara. „Synthesis of methylated quercetin analogues for enhancement of radical-scavenging activity“. RSC Advances 7, Nr. 29 (2017): 17968–79. http://dx.doi.org/10.1039/c7ra02329d.

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Duan, Yu, Na Sun, Min Xue, Xiaolan Wang und Hu Yang. „Synthesis of regioselectively acylated quercetin analogues with improved antiplatelet activity“. Molecular Medicine Reports 16, Nr. 6 (12.10.2017): 9735–40. http://dx.doi.org/10.3892/mmr.2017.7781.

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Fernández-Aparicio, Mónica, Marco Masi, Alessio Cimmino, Susana Vilariño und Antonio Evidente. „Allelopathic Effect of Quercetin, a Flavonoid from Fagopyrum esculentum Roots in the Radicle Growth of Phelipanche ramosa: Quercetin Natural and Semisynthetic Analogues Were Used for a Structure-Activity Relationship Investigation“. Plants 10, Nr. 3 (13.03.2021): 543. http://dx.doi.org/10.3390/plants10030543.

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Allelopathic potential of buckwheat roots on the radicle growth of the broomrape weed species Orobanche cumana and Phelipanche ramosa was studied. Buckwheat root exudates induced a significant growth inhibition in P. ramosa radicles but radicles of O. cumana were not affected. Among the metabolites present in the root organic extract we identified the flavonol quercetin and the stilbene p-coumaric acid methyl ester with only quercetin showing inhibitory effect on P. ramosa. The activity of quercetin was compared with other two similar flavanoids, the flavone apigenin and the dihydroflavanol 3-O-acetylpadmatin extracted respectively from Lavandula stoechas and Dittrichia viscosa plants. In this comparative assay only 3-O-acetylpadmatin besides quercetin, showed inhibition activity of radicle growth while apigenin was inactive. These results indicated that the presence of two ortho-free hydroxy groups of C ring, like catechol, could be an important feature to impart activity while the carbon skeleton of B ring and substituents of both A and B rings are not essential. Besides reduction of radicle growth, haustorium induction was observed at the tip of P. ramosa radicles treated with quercetin which swelled and a layer of papillae was formed. Activity of quercetin on haustorium induction in P. ramosa was assayed in comparison with the known haustorium-inducing factor 2,6-dimethoxy-p-benzoquinone (DMBQ) and a three partial methyl ether derivatives semisynthetized from quercetin. Results indicated that P. ramosa haustorium was induced by DMBQ at concentrations of 1–0.5 mM and quercetin and its derivatives at concentration range 0.1–0.05 mM.

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Litvin, V. A., und R. A. Njoh. „Quercetin as a precursor in the synthesis of analogues of fulvic acids and their antibacterial properties“. Voprosy Khimii i Khimicheskoi Tekhnologii, Nr. 2 (März 2021): 56–64. http://dx.doi.org/10.32434/0321-4095-2021-135-2-56-64.

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A simple, fast and effective method for producing synthetic substances with properties similar to natural humic substances has been proposed. The synthesis method is based on the oxidation of quercetin by molecular oxygen in an alkaline medium, followed by conversion to the acid form by passing through a cation exchange column. Study of elemental and functional compositions, spectral properties (UV/Vis and IR range) and redox characteristics allowed qualifying the resulting product as a synthetic fulvic acid. The enhanced antibacterial properties of the obtained synthetic product were established. The minimum concentration of inhibition of synthetic fulvic acid derived from quercetin is 25 g mL–1, which is in 100 times less than for natural humic substances.

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Atala, Elias, Jocelyn Fuentes, Maria Jose Wehrhahn und Hernan Speisky. „Oxidation of Quercetin and Its Structural Analogues Differentially Affects Its Antioxidant Properties“. Free Radical Biology and Medicine 100 (November 2016): S93. http://dx.doi.org/10.1016/j.freeradbiomed.2016.10.231.

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Nayak, Yogendra, Venkatachalam Hillemane, Vijay Kumar Daroji, B. S. Jayashree und M. K. Unnikrishnan. „Antidiabetic Activity of Benzopyrone Analogues in Nicotinamide-Streptozotocin Induced Type 2 Diabetes in Rats“. Scientific World Journal 2014 (2014): 1–12. http://dx.doi.org/10.1155/2014/854267.

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Benzopyrones are proven antidiabetic drug candidate in diabetic drug discovery. In this view novel synthetic benzopyrone analogues were selected for testing in experimental diabetes. Type 2 diabetes (T2D) was induced in Wistar rats by streptozotocin (60 mg/kg, i.p.) followed by nicotinamide (120 mg/kg i.p.). Rats having fasting blood glucose (FBG) >200 mg/dL, 7 days after T2D-induction, are selected for the study. Test compounds and standard treatment were continued for 15 days. FBG, oral glucose tolerance test (OGTT), and insulin tolerance test (ITT) were determined on 21st day after induction of T2D. Plasma lipids and serum insulin were estimated. Homeostatic model assessment (HOMA-IR) was then calculated from serum insulin. Rats were sacrificed and pancreas was isolated for histopathological observations. Oxidative stress markers were estimated in liver homogenate. Quercetin, a natural product with benzopyrone ring, showed significant hypoglycemic activity comparable to glibenclamide. Treatment with test compounds lowered the FBG and insulin resistance was significant alleviated as determined by OGTT, HOMA-IR, and ITT. There was significant normalisation of liver antioxidant enzymes compared to diabetic rats indicating that all the synthesised benzopyrone analogues are beneficial in reducing oxidative stress and are on par with the standard quercetin and glibenclamide in experimental T2D.

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Primikyri, Alexandra, Eleftheria Hatzimichael, Evdoxia Karali, Eleftherios Kostaras, Michalis Manztaris, Jae-Sun Shin, Seung-Wook Chi et al. „Decoding The BH3-Mimetic Pro-Apoptotic Activity Of Quercetin In Jurkat Cells“. Blood 122, Nr. 21 (15.11.2013): 1672. http://dx.doi.org/10.1182/blood.v122.21.1672.1672.

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Abstract Deregulation of apoptosis contributes largely to the pathogenesis of lymphoid neoplasms allowing the expansion of cell clones that develop resistance to drug-induced cell death. Therefore, subverting inherent resistance to apoptosis is a very challenging therapeutic issue and developing small molecules that can mimic the BH3 domain of the pro-apoptotic Bcl-2 family proteins appears to offer such potentials. Natural products, a rich source of compounds with BH3 mimetic activity, make a sound basis for such an approach. Quercetin, a natural polyphenol, has drawn much attention because it exerts anticancer cytotoxic effects, while sparing normal cells. Pro-apoptotic effects of quercetin have been shown in human lymphoma and leukemic cells and have been associated with Bcl-2 and Mcl-1 downregulation and Bax conformational activation. We undertook a multidisciplinary approach to elucidate the mode of action of quercetin, including cytotoxicity cell assays, biochemical approaches (pull down assays), NMR spectroscopy and docking calculations. We demonstrate that quercetin binds directly to the BH3 domain of the anti-apoptotic Bcl-2 and Bcl-xL proteins, exhibiting BH3-mimetic properties. Specifically, functional cytotoxicity assays of quercetin in Jurkat T-cell leukemic lines, Jurkat Bcl-2 and Jurkat Puro, indicated that quercetin binds to Bcl-2 protein. The direct binding of quercetin to Bcl-2 and to Bcl-xL was biochemically validated using pull down assays. NMR chemical shift perturbation experiments and docking calculations finally revealed that quercetin was bound to the pro-apoptotic BH3-binding site of the anti-apoptotic Bcl-2 family proteins (Figure 1). This property classifies quercetin as a natural flavonoid with BH3 mimetic activity, capable of driving leukemic cells to apoptosis. These results explain the cytotoxic effects of quercetin on Jurkat cells. These data can serve as a basis to consider studying BH3 mimetic natural products as adjuncts in the therapeutic approaches of lymphoid neoplasms in combination with chemotherapy, and can also provide a starting structure for developing novel potent analogues for the treatment of blood cancers.Figure 1Modeling (3D) the complex of quercetin with Bcl-2 (A) and Bcl-xl (B). Quercetin occupies the deep hydrophobic cleft in both proteins making an extended interaction network. The relevant residues are normally occupied by the pro-apoptotic Bak/Bad BH3 binding site in the complexFigure 1. Modeling (3D) the complex of quercetin with Bcl-2 (A) and Bcl-xl (B). Quercetin occupies the deep hydrophobic cleft in both proteins making an extended interaction network. The relevant residues are normally occupied by the pro-apoptotic Bak/Bad BH3 binding site in the complex Disclosures: No relevant conflicts of interest to declare.

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Nör, Carolina, Ana Paula Machado Bernardi, Juliana Schulte Haas, Jan Schripsema, Sandra Beatriz Rech und Gilsane Lino Von Poser. „Phenolic Constituents of Hypericum Flowers“. Natural Product Communications 3, Nr. 2 (Februar 2008): 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300227.

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Species of Hypericum accumulate phenolic compounds with the phloroglucinol substitution pattern, and there are many reports of such substances isolated from the aerial parts of the plants. In this study, flowers of plants grown in south Brazil were analyzed by means of HPLC, verifying the presence of benzopyrans in H. polyanthemum and dimeric phloroglucinol derivatives in H. caprifoliatum, H. connatum, H. myrianthum and H. polyanthemum. All flowers presented flavonoids, mainly quercetin derivatives, whereas hypericin and analogues were not detected.

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Coorssen, J. R. „Phospholipase activation and secretion: evidence that PLA2, PLC, and PLD are not essential to exocytosis“. American Journal of Physiology-Cell Physiology 270, Nr. 4 (01.04.1996): C1153—C1163. http://dx.doi.org/10.1152/ajpcell.1996.270.4.c1153.

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Numerous studies have identified phospholipase metabolites as membrane fusogens, and phospholipase D (PLD) (J.R. Coorssen and R.J. Haslam. FEBS Lett. 316: 170-174, 1993), C (PLC), and A2 (PLA2) activities correlate with secretion. Do these enzymes have essential or modulatory roles? This study confirms that secretion does not require Ca2+ or PLC (Coorssen et al. Cell Regul. 1: 1027-1041, 1990). Arachidonic acid (AA), phosphatidic acid (PA) and analogues, exogenous metabolites of PLA2 and PLD, were tested in electropermeabilized human platelets. AA potentiated guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S)-induced secretion, and eicosanoids were not essential. Endogenous [3H]AA formation correlated with GTP gamma S-induced secretion, and phorbol 12-myristate 13-acetate (PMA) promoted these effects. Inhibitors were used to probe phospholipase influences on secretion. Only PLD inhibitors blocked secretion. However, PMA blocked inhibition of protein kinase C (PKC) and secretion by quercetin, suggesting that PA formed by PLD supports PKC activation and GTP gamma S-induced secretion. Thus PA analogues had no effect alone but enhanced GTP gamma S-induced PKC activity and secretion. Slower PLD activation compared with secretion also indicates a nonessential role. This is the first report of a Ca(2+)-independent PLA2 activity in human platelets, use of quercetin as a PLD inhibitor, and dissociation of PLA2, PLC, and PLD activities from secretion. No major phospholipase activities are essential to the final steps in exocytosis, but modulatory roles are indicated.

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Singh, Salam Pradeep, Rocktotpal Konwarh, Bolin Kumar Konwar und Niranjan Karak. „Molecular docking studies on analogues of quercetin with d-alanine:d-alanine ligase of Helicobacter pylori“. Medicinal Chemistry Research 22, Nr. 5 (07.09.2012): 2139–50. http://dx.doi.org/10.1007/s00044-012-0207-7.

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Tasdemir, Deniz, Marcel Kaiser, Reto Brun, Vanessa Yardley, Thomas J. Schmidt, Fatma Tosun und Peter Rüedi. „Antitrypanosomal and Antileishmanial Activities of Flavonoids and Their Analogues: In Vitro, In Vivo, Structure-Activity Relationship, and Quantitative Structure-Activity Relationship Studies“. Antimicrobial Agents and Chemotherapy 50, Nr. 4 (April 2006): 1352–64. http://dx.doi.org/10.1128/aac.50.4.1352-1364.2006.

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ABSTRACT Trypanosomiasis and leishmaniasis are important parasitic diseases affecting millions of people in Africa, Asia, and South America. In a previous study, we identified several flavonoid glycosides as antiprotozoal principles from a Turkish plant. Here we surveyed a large set of flavonoid aglycones and glycosides, as well as a panel of other related compounds of phenolic and phenylpropanoid nature, for their in vitro activities against Trypanosoma brucei rhodesiense, Trypanosoma cruzi, and Leishmania donovani. The cytotoxicities of more than 100 compounds for mammalian L6 cells were also assessed and compared to their antiparasitic activities. Several compounds were investigated in vivo for their antileishmanial and antitrypanosomal efficacies in mouse models. Overall, the best in vitro trypanocidal activity for T. brucei rhodesiense was exerted by 7,8-dihydroxyflavone (50% inhibitory concentration [IC50], 68 ng/ml), followed by 3-hydroxyflavone, rhamnetin, and 7,8,3′,4′-tetrahydroxyflavone (IC50s, 0.5 μg/ml) and catechol (IC50, 0.8 μg/ml). The activity against T. cruzi was moderate, and only chrysin dimethylether and 3-hydroxydaidzein had IC50s less than 5.0 μg/ml. The majority of the metabolites tested possessed remarkable leishmanicidal potential. Fisetin, 3-hydroxyflavone, luteolin, and quercetin were the most potent, giving IC50s of 0.6, 0.7, 0.8, and 1.0 μg/ml, respectively. 7,8-Dihydroxyflavone and quercetin appeared to ameliorate parasitic infections in mouse models. Generally, the test compounds lacked cytotoxicity in vitro and in vivo. By screening a large number of flavonoids and analogues, we were able to establish some general trends with respect to the structure-activity relationship, but it was not possible to draw clear and detailed quantitative structure-activity relationships for any of the bioactivities by two different approaches. However, our results can help in directing the rational design of 7,8-dihydroxyflavone and quercetin derivatives as potent and effective antiprotozoal agents.

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Jahangir, Muhammad, Atta-ur-Rehman, Ibrahim Bayoumi Abdel Farid, Robert Verpoorte, Imran Khan und Jiangnan Peng. „NMR-Based Metabolomics for Geographical Discrimination of Adhatoda vasica Leaves“. Plants 12, Nr. 3 (18.01.2023): 453. http://dx.doi.org/10.3390/plants12030453.

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Adhatoda vasica (L.), Nees is a widespread plant in Asia. It is used in Ayurvedic and Unani medications for the management of various infections and health disorders, especially as a decoction to treat cough, chronic bronchitis, and asthma. Although it has a diverse metabolomic profile, this plant is particularly known for its alkaloids. The present study is the first to report a broad range of present compounds, e.g., α-linolenic acid, acetate, alanine, threonine, valine, glutamate, malate, fumaric acid, sucrose, β-glucose, kaempferol analogues, quercetin analogues, luteolin, flavone glucoside, vasicine and vasicinone, which were identified by NMR spectroscopy-based metabolomics. Multivariate data analysis was used to analyze 1H-NMR bucketed data from a number of Adhatoda vasica leave samples collected from eight different regions in Pakistan. The results showed large variability in metabolomic fingerprints. The major difference was on the basis of longitude/latitude and altitude of the areas, with both primary and secondary metabolites discriminating the samples from various regions.

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Biswas, Subhankar, Neetinkumar D. Reddy, B. S. Jayashree und C. Mallikarjuna Rao. „Evaluation of Novel 3-Hydroxyflavone Analogues as HDAC Inhibitors against Colorectal Cancer“. Advances in Pharmacological Sciences 2018 (27.12.2018): 1–14. http://dx.doi.org/10.1155/2018/4751806.

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Alteration of epigenetic enzymes is associated with the pathophysiology of colon cancer with an overexpression of histone deacetylase 8 (HDAC8) enzyme in this tissue. Numerous reports suggest that targeting HDAC8 is a viable strategy for developing new anticancer drugs. Flavonols provide a rich source of molecules that are effective against cancer; however, their clinical use is limited. The present study investigated the potential of quercetin and synthetic 3-hydroxyflavone analogues to inhibit HDAC8 enzyme and evaluated their anticancer property. Synthesis of the analogues was carried out, and cytotoxicity was determined using MTT assay. Nonspecific and specific HDAC enzyme inhibition assays were performed followed by the expression studies of target proteins. Induction of apoptosis was studied through annexin V and caspase 3/7 activation assay. Furthermore, the analogues were assessed against in vivo colorectal cancer. Among the synthesized analogues, QMJ-2 and QMJ-5 were cytotoxic against HCT116 cells with an IC50 value of 68 ± 2.3 and 27.4 ± 1.8 µM, respectively. They inhibited HDAC enzyme in HCT116 cells at an IC50 value of 181.7 ± 22.04 and 70.2 ± 4.3 µM, respectively, and inhibited human HDAC8 and 1 enzyme at an IC50 value of <50 µM with QMJ-5 having greater specificity towards HDAC8. A reduction in the expression of HDAC8 and an increase in acetyl H3K9 expression were observed with the synthesized analogues. Both QMJ-2 and QMJ-5 treatment induced apoptosis through the activation of caspase 3/7 evident from 55.70% and 83.55% apoptotic cells, respectively. In vivo studies revealed a significant decrease in colon weight to length ratio in QMJ-2 and QMJ-5 treatment groups compared to DMH control. Furthermore, a reduction in aberrant crypt foci formation was observed in the treatment groups. The present study demonstrated the potential of novel 3-hydroxyflavone analogues as HDAC8 inhibitors with anticancer property against colorectal cancer.

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Hossion, Abugafar M. L., Yoshito Zamami, Rafiya K. Kandahary, Tomofusa Tsuchiya, Wakano Ogawa, Akimasa Iwado und Kenji Sasaki. „Quercetin Diacylglycoside Analogues Showing Dual Inhibition of DNA Gyrase and Topoisomerase IV as Novel Antibacterial Agents“. Journal of Medicinal Chemistry 54, Nr. 11 (09.06.2011): 3686–703. http://dx.doi.org/10.1021/jm200010x.

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Cai, Weirong, Yong Chen, Liangliang Xie, Hong Zhang und Chunyuan Hou. „Characterization and density functional theory study of the antioxidant activity of quercetin and its sugar-containing analogues“. European Food Research and Technology 238, Nr. 1 (14.09.2013): 121–28. http://dx.doi.org/10.1007/s00217-013-2091-x.

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Darko, Mitrović. „In silico analysis of molecular descriptors for quercetin analogues: a way to improve blood–brain barrier permeation“. Intrinsic Activity 11, Suppl.1 (22.09.2023): A2.25. http://dx.doi.org/10.25006/ia.11.s1-a2.25.

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Adamus-Grabicka, Angelika A., Magdalena Markowicz-Piasecka, Marcin Cieślak, Karolina Królewska-Golińska, Paweł Hikisz, Joachim Kusz, Magdalena Małecka und Elzbieta Budzisz. „Biological Evaluation of 3-Benzylidenechromanones and Their Spiropyrazolines-Based Analogues“. Molecules 25, Nr. 7 (01.04.2020): 1613. http://dx.doi.org/10.3390/molecules25071613.

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A series of 3-benzylidenechrmanones 1, 3, 5, 7, 9 and their spiropyrazoline analogues 2, 4, 6, 8, 10 were synthesized. X-ray analysis confirms that compounds 2 and 8 crystallize in a monoclinic system in P21/n space groups with one and three molecules in each asymmetric unit. The crystal lattice of the analyzed compounds is enhanced by hydrogen bonds. The primary aim of the study was to evaluate the anti-proliferative potential of 3-benzylidenechromanones and their spiropyrazoline analogues towards four cancer cell lines. Our results indicate that parent compounds 1 and 9 with a phenyl ring at C2 have lower cytotoxic activity against cancer cell lines than their spiropyrazolines analogues. Analysis of IC50 values showed that the compounds 3 and 7 exhibited higher cytotoxic activity against cancer cells, being more active than the reference compound (4-chromanone or quercetin). The results of this study indicate that the incorporation of a pyrazoline ring into the 3-arylideneflavanone results in an improvement of the compounds’ activity and therefore it may be of use in the search of new anticancer agents. Further analysis allowed us to demonstrate the compounds to have a strong inhibitory effect on the cell cycle. For instance, compounds 2, 10 induced 60% of HL-60 cells to be arrested in G2/M phase. Using a DNA-cleavage protection assay we also demonstrated that tested compounds interact with DNA. All compounds at the concentrations corresponding to cytotoxic properties are not toxic towards red blood cells, and do not contribute to hemolysis of RBCs.

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Kondhare, Dasharath, Sushma Deshmukh und Harshad Lade. „Curcumin Analogues with Aldose Reductase Inhibitory Activity: Synthesis, Biological Evaluation, and Molecular Docking“. Processes 7, Nr. 7 (02.07.2019): 417. http://dx.doi.org/10.3390/pr7070417.

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Curcumin, a constituent of Curcuma longa, has shown numerous biological and pharmacological activities, including antidiabetic effects. Here, a novel series of curcumin analogues were synthesized and evaluated for in vitro inhibition of aldose reductase (AR), the first and rate-limiting enzyme of the polyol pathway, which plays a key role in the onset and progression of diabetic complications. Biological activity studies showed that all the curcuminoids exhibited moderate to good AR inhibitory (ARI) activities compared with that of the quercetin standard. Importantly, compounds 8d, 8h, 9c, 9e, and 10g demonstrated promising ARI activities, with the 50% inhibitory concentration (IC50) values of 5.73, 5.95, 5.11, 5.78, and 5.10 µM, respectively. Four other compounds exhibited IC50 values in the range of 6.04–6.18 µM. Methyl and methoxy derivatives showed a remarkable ARI potential compared with that of other substitutions on the aromatic ring. Molecular docking experiments demonstrated that the most active curcuminoid (10g) was able to favorably bind in the active site of the AR enzyme. The potent ARI activities exhibited by the curcuminoids were attributed to their substitution patterns on the aromatic moiety, which may provide novel leads in the development of therapeutics for the treatment of diabetic complications.

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De Sousa Lages, Adriana, Valentim Lopes, João Horta, João Espregueira-Mendes, Renato Andrade und Alexandre Rebelo-Marques. „Therapeutics That Can Potentially Replicate or Augment the Anti-Aging Effects of Physical Exercise“. International Journal of Molecular Sciences 23, Nr. 17 (01.09.2022): 9957. http://dx.doi.org/10.3390/ijms23179957.

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Globally, better health care access and social conditions ensured a significant increase in the life expectancy of the population. There is, however, a clear increase in the incidence of age-related diseases which, besides affecting the social and economic sustainability of countries and regions around the globe, leads to a decrease in the individual’s quality of life. There is an urgent need for interventions that can reverse, or at least prevent and delay, the age-associated pathological deterioration. Within this line, this narrative review aims to assess updated evidence that explores the potential therapeutic targets that can mimic or complement the recognized anti-aging effects of physical exercise. We considered pertinent to review the anti-aging effects of the following drugs and supplements: Rapamycin and Rapamycin analogues (Rapalogs); Metformin; 2-deoxy-D-glucose; Somatostatin analogues; Pegvisomant; Trametinib; Spermidine; Fisetin; Quercetin; Navitoclax; TA-65; Resveratrol; Melatonin; Curcumin; Rhodiola rosea and Caffeine. The current scientific evidence on the anti-aging effect of these drugs and supplements is still scarce and no recommendation of their generalized use can be made at this stage. Further studies are warranted to determine which therapies display a geroprotective effect and are capable of emulating the benefits of physical exercise.

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Ren, Yulin, Tyler Frank, Gunnar Meyer, Jizhou Lei, Jessica R. Grebenc, Ryan Slaughter, Yu G. Gao und A. Douglas Kinghorn. „Potential Benefits of Black Chokeberry (Aronia melanocarpa) Fruits and Their Constituents in Improving Human Health“. Molecules 27, Nr. 22 (13.11.2022): 7823. http://dx.doi.org/10.3390/molecules27227823.

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Aronia berry (black chokeberry) is a shrub native to North America, of which the fresh fruits are used in the food industry to produce different types of dietary products. The fruits of Aronia melanocarpa (Aronia berries) have been found to show multiple bioactivities potentially beneficial to human health, including antidiabetic, anti-infective, antineoplastic, antiobesity, and antioxidant activities, as well as heart-, liver-, and neuroprotective effects. Thus far, phenolic compounds, such as anthocyanins, cyanidins, phenolic acids, proanthocyanidins, triterpenoids, and their analogues have been identified as the major active components of Aronia berries. These natural products possess potent antioxidant activity, which contributes to the majority of the other bioactivities observed for Aronia berries. The chemical components and the potential pharmaceutical or health-promoting effects of Aronia berries have been summarized previously. The present review article focuses on the molecular targets of extracts of Aronia berries and the examples of promising lead compounds isolated from these berries, including cyanidin-3-O-galactoside, chlorogenic acid, quercetin, and ursolic acid. In addition, presented herein are clinical trial investigations for Aronia berries and their major components, including cancer clinical trials for chlorogenic acid and COVID-19 trial studies for quercetin. Additionally, the possible development of Aronia berries and their secondary metabolites as potential therapeutic agents is discussed. It is hoped that this contribution will help stimulate future investigations on Aronia berries for the continual improvement of human health.

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Bouktaib, Mohamed, Stéphane Lebrun, Aziz Atmani und Christian Rolando. „Hemisynthesis of all the O-monomethylated analogues of quercetin including the major metabolites, through selective protection of phenolic functions“. Tetrahedron 58, Nr. 50 (Dezember 2002): 10001–9. http://dx.doi.org/10.1016/s0040-4020(02)01306-6.

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D.Bharathi, P. Valentina und N. Ramalakshmi. „MOLECULAR DOCKING OF NOVEL BENZOPYRAN ANALOGUES AND INHIBITION PROPERTIES OF ANTIDIABETIC AGENTS AGAINST α-AMYLASE AND αGLUCOSIDASE“. RASAYAN Journal of Chemistry 15, Nr. 04 (2022): 2873–78. http://dx.doi.org/10.31788/rjc.2022.1547075.

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Alpha amylase and alpha-glucosidase inhibitors play a key role in treating diabetes mellitus. Based on this idea the present study aimed in designing different benzopyran analogs and investigate the binding interaction with protein PDB: 1HNY and PDB:5NN3 through molecular docking by autodockpyrx. The results evaluated by docking studies found that different substituted derivatives of 4-Hydroxycoumarine, 3-acetyl 4-hydroxy coumarin, 8 hydroxycoumarine, 7-hydroxycoumarine, 4-hydroxy, 5-methoxycoumarine compounds and compared with standard quercetin which is the target protein. The compound showing the best score for 1HNY is hydroxyl substituent with dicyandiamide,4-methyl carbothioamide, 3-methoxy formamide, 3-methoxycarbothioamide and for 5NN3 is 4- methyl formamide,4-Fluro carbohioamide. Totally 107 compounds were subjected to docking and the selected fifteen potent compounds were subjected to predict the molecular property, drug-likeness, absorption, distribution, and metabolism analysis by using online free software Molinspiration and Swiss ADME, which were satisfied with the Lipinski rule of 5 which plays an important role in filtering the protocol. The filtered compounds showed 0 violations for the physiochemical properties of the molecule

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Burchinsky, S. G., und М. A. Kalinichenko. „Neurogeroprotection in neurological practice: new possibilities“. Medicine of Ukraine, Nr. 2-3(258-259) (17.06.2022): 25–30. http://dx.doi.org/10.37987/1997-9894.2022.2-3(258-259).264051.

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The article is devoted to the issues of effective pharmacotherapy of neurodegenerative and vascular pathology of the CNS, which is possible due to the adequate impact on the fundamental mechanisms of brain aging. Comprehensive, comprehensive consideration of the mentioned mechanisms allows to reasonably approach the problem of optimization of neuroheroprotection and choice of a specific drug. Today, the most promising neuroheroprotectors are quercetin, L-carnitine and L-arginine. A rational combination of all three mentioned components is a domestic drug - L-ACC, which has no analogues in the pharmaceutical market. The use of combined neurogeroprotectors, in particular L-ACC, opens up new prospects for expanding the adaptive-compensatory capabilities of the brain, slowing down its aging processes and the manifestation of age-related pathology, helps to increase the duration and quality of life, the formation of stress resistance and reduces the cost of treatment.

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Bonaldo, Federico, Fulvio Mattivi, Daniele Catorci, Panagiotis Arapitsas und Graziano Guella. „H/D Exchange Processes in Flavonoids: Kinetics and Mechanistic Investigations“. Molecules 26, Nr. 12 (10.06.2021): 3544. http://dx.doi.org/10.3390/molecules26123544.

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Several classes of flavonoids, such as anthocyanins, flavonols, flavanols, and flavones, undergo a slow H/D exchange on aromatic ring A, leading to full deuteration at positions C(6) and C(8). Within the flavanol class, H-C(6) and H-C(8) of catechin and epicatechin are slowly exchanged in D2O to the corresponding deuterated analogues. Even quercetin, a relevant flavonol representative, shows the same behaviour in a D2O/DMSOd6 1:1 solution. Detailed kinetic measurements of these H/D exchange processes are here reported by exploiting the time-dependent changes of their peak areas in the 1H-NMR spectra taken at different temperatures. A unifying reaction mechanism is also proposed based on our detailed kinetic observations, even taking into account pH and solvent effects. Molecular modelling and QM calculations were also carried out to shed more light on several molecular details of the proposed mechanism.

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Zhang, Jun-Sheng, Han-Zhuang Weng, Jia-Luo Huang, Gui-Hua Tang und Sheng Yin. „Anti-inflammatory Ingenane Diterpenoids from the Roots of Euphorbia kansui“. Planta Medica 84, Nr. 18 (25.06.2018): 1334–39. http://dx.doi.org/10.1055/a-0646-4306.

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AbstractBioassay-guided fractionation of the ethanolic extract of the roots of Euphorbia kansui led to the isolation of two new ingenane diterpenoids, euphorkans A (1) and B (2), together with 16 known analogues (3 – 18). Their structures were determined by combined spectral and chemical methods. All the isolates were evaluated for their inhibitory effects on lipopolysaccharide-induced nitric oxide production in RAW264.7 macrophage cells. Compounds 1 – 6 and 10 – 13 exhibited pronounced inhibitory activity with IC50 values in the range of 2.78 – 10.6 µM, and were more potent than the positive control, quercetin (IC50 = 15.8 µM). Compounds 1 and 5 were selected for further assays toward the key inflammation mediators TNF-α and IL-6, and showed a significant inhibition in a dose-dependent manner. The preliminary mechanistic study revealed that 1 and 5 inhibited NF-κB activity, which may exert a role in their anti-inflammatory activity.

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Zou, Xiang-Yue, Ying-Jie He, Yi-Hui Yang, Xin-Pei Yan, Zhang-Bao Li und Hua Yang. „Systematic Identification of Bioactive Compositions in Leaves of Morus Cultivars Using UHPLC-ESI-QTOF-MS/MS and Comprehensive Screening of High-Quality Resources“. Separations 9, Nr. 3 (15.03.2022): 76. http://dx.doi.org/10.3390/separations9030076.

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Morus spp. leaves (MSLs) show various beneficial effects in the treatment of metabolic-related diseases, which have created a growing interest in MSL development as dietary supplements and functional foods. The illustration of chemical compositions and screening of high-quality MSL resources are therefore necessary for further application. This study developed a new UHPLC-ESI-QTOF-MS/MS strategy of in-source collision-induced dissociation (IS-CID) and target collision-cell CID (TCC-CID) to quickly capture analogues with consistent skeleton, and combined global natural product social molecular networking (GNPS) to efficiently annotate bioactive phytochemicals in MSLs. For the results, 49 bioactive ingredients, including quercetin-type flavonoids, kaempferol-type flavonoids, chlorogenic acid isomers, 1-deoxynojirimycin, γ-aminobutyric acid, amino acids, and unsaturated fatty acids, were systematically identified in MSLs for the first time. Quantification for the typical components was simultaneously carried out in MSLs of 90 Morus resources collected from different locations. Partial least squares discriminant analysis (PLS-DA) indicated that quercetin-3-O-(6″-O-malonyl)-glucoside, rutin, kaempferol-3-O-(6″-O-malonyl)-glucoside, kaempferol-3-O-rutinoside, and chlorogenic acid showed high variable importance in the project (VIP > 1) that were significant constituents for the differences between MSL species. Then, high-quality MSLs were comprehensively screened in multiple Morus cultivars based on the criteria importance through intercriteria correlation (CRITIC) method. This study presented an efficient strategy to annotate bioactive compounds, revealed the difference of bioactive components in MSLs, and provided important information for the high-value production of Morus cultivars in food and supplement fields.

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Abdizadeh, Tooba. „Efficacy Evaluation of Quercetin and Its Analogues on the Main Protease Enzyme of the COVID-19 Using Molecular Docking Studies“. journal of ilam university of medical sciences 30, Nr. 4 (01.10.2022): 66–85. http://dx.doi.org/10.52547/sjimu.30.4.66.

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Chen, Jih-Jung, Tzong-Huei Lee und Ming-Jen Cheng. „Secondary Metabolites with Anti-Inflammatory Activities from an Actinobacteria Herbidospora daliensis“. Molecules 27, Nr. 6 (14.03.2022): 1887. http://dx.doi.org/10.3390/molecules27061887.

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Bioassay-guided fractionation of extracts derived from solid cultures of a Herbidospora daliensis originating from Taiwan led to the isolation of five new compounds, for which we propose the name herbidosporadalins A–E (1–5), one isolated for the first time, herbidosporadalin F (6), together with two known compounds (7 & 8). Their structures were elucidated by spectroscopic analyses, including 1D- and 2D-NMR experiments with those of known analogues, and on the basis of HR-EI-MS mass spectrometry, their anti-inflammatory activities were also evaluated. Of these isolates, herbidosporadalin A (1), B (2), F (6) and G (8) showed NO inhibitory activity, with IC50 values of 11.8 ± 0.9, 7.1 ± 2.9, 17.8 ± 1.7, and 13.3 ± 6.5 μM, stronger than the positive control quercetin (IC50 = 36.8 ± 1.3 μM). To the best of our knowledge, this is the first report on 3,4-seco-friedelane metabolites (5, 6 & 8) from the genus Herbidospora.

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Thangasamy, Thilakavathy, Sivanandane Sittadjody, Kirsten H. Limesand und Randy Burd. „Tyrosinase Overexpression Promotes ATM-Dependent p53 Phosphorylation by Quercetin and Sensitizes Melanoma Cells to Dacarbazine“. Analytical Cellular Pathology 30, Nr. 5 (01.01.2008): 371–87. http://dx.doi.org/10.1155/2008/764086.

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Dacarbazine (DTIC) has been used for the treatment of melanoma for decades. However, monotherapy with this chemotherapeutic agent results only in moderate response rates. To improve tumor response to DTIC current clinical trials in melanoma focus on combining a novel targeted agent with chemotherapy. Here, we demonstrate that tyrosinase which is commonly overexpressed in melanoma activates the bioflavonoid quercetin (Qct) and promotes an ataxia telangiectasia mutated (ATM)-dependent DNA damage response. This response sensitizes melanoma cells that overexpress tyrosinase to DTIC. In DB-1 melanoma cells that overexpress tyrosinase (Tyr+ cells), the threshold for phosphorylation of ATM and p53 at serine 15 was observed at a low dose of Qct (25 μM) when compared to the mock transfected pcDNA3 cells, which required a higher dose (75 μM). Both pcDNA3 and Tyr+ DB-1 cells demonstrated similar increases in phosphorylation of p53 at other serine sites, but in the Tyr+ cells, DNApk expression was found to be reduced compared to control cells, indicating a shift towards an ATM-mediated response. The DB-1 control cells were resistant to DTIC, but were sensitized to apoptosis with high dose Qct, while Tyr+ cells were sensitized to DTIC with low or high dose Qct. Qct also sensitized SK Mel 5 (p53 wildtype) and 28 (p53 mutant) cells to DTIC. However, when SK Mel 5 cells were transiently transfected with tyrosinase and treated with Qct plus DTIC, SK Mel 5 cells demonstrated a more than additive induction of apoptosis. Therefore, this study demonstrates that tyrosinase overexpression promotes an ATM-dependent p53 phosphorylation by Qct treatment and sensitizes melanoma cells to dacarbazine. In conclusion, these results suggest that Qct or Qct analogues may significantly improve DTIC response rates in tumors that express tyrosinase.

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Ganesh, Deepa, Hans-Peter Fuehrer, Peter Starzengrüber, Paul Swoboda, Wasif Ali Khan, Johannes A. B. Reismann, Milena S. K. Mueller, Peter Chiba und Harald Noedl. „Antiplasmodial activity of flavonol quercetin and its analogues in Plasmodium falciparum: evidence from clinical isolates in Bangladesh and standardized parasite clones“. Parasitology Research 110, Nr. 6 (04.01.2012): 2289–95. http://dx.doi.org/10.1007/s00436-011-2763-z.

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Vlasenko, Ludmila, und Kseniya Atlanderova. „Assessment (in vitro) toxicity of small molecules of plant origin“. E3S Web of Conferences 390 (2023): 07022. http://dx.doi.org/10.1051/e3sconf/202339007022.

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Small molecules of plant origin can have different effects on bacterial cells. At present, it is of great interest to determine the toxic effects of such compounds in order to assess the potential of their use in veterinary medicine and medicine. The aim of this work was to evaluate the toxicity of various chemically synthesized small molecules of plant origin using a bacterial luminescent biosensor based on Escherichia coli and a cell culture of the freshwater ciliate Stylonychia mytilus. Cinnamic aldehyde had the greatest toxic effect on the E. coli MG1655 pXen7 lux-biosensor, which was expressed in a significant decrease in the luminescence level of the strain compared to the control. Quercetin in the concentration range used did not affect the luminescence intensity of the lux-biosensor. Coumarin and vanillin were characterized by a similar manifestation of the toxic effect. Similar results were also confirmed using S. mytilus as a test object. The results obtained expand the understanding of the possible toxic effect of phytochemicals, which can be used in the development of feed additives in animal husbandry (as analogues of feed antibiotics).

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Moalin, Mohamed, Gino P. F. van Strijdonck, Aalt Bast und Guido R. M. M. Haenen. „Competition between Ascorbate and Glutathione for the Oxidized Form of Methylated Quercetin Metabolites and Analogues: Tamarixetin, 4′O-Methylquercetin, Has the Lowest Thiol Reactivity“. Journal of Agricultural and Food Chemistry 60, Nr. 36 (27.08.2012): 9292–97. http://dx.doi.org/10.1021/jf302068v.

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Hladkykh, Feydor V. „Preventive and therapeutic strategies of pharmaco-correction gastropathy induced by nonsteroidal anti-inflammatory drugs“. Reviews on Clinical Pharmacology and Drug Therapy 15, Nr. 4 (15.12.2017): 14–23. http://dx.doi.org/10.17816/rcf15414-23.

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Today the problem of prevention and treatment of gastropathy associated with nonsteroidal anti-inflammatory drugs has not lost its relevance. In order to reduce the ulcerogenicity of non-steroidal anti-inflammatory drugs, it is classically accepted to supplement the therapy scheme with preparations of other pharmacological groups - antacids, alginates, M-cholinoblockers, gastrin receptor antagonists, H2-histamine blockers, proton pump inhibitors, synthetic analogues of prostaglandins or stimulators of their synthesis, reparants, gastroprotectors. Nowadays, it was suggested I was suggested the use of drugs which have pharmacological properties polyvector (vinboron, thiotriazoline et al.). Also, the scientists started of combined preparations “NSAIDs + drugs other pharmacological groups” - indotril (indomethacin + thiotriazoline) diklokor (diclofenac + quercetin) Artrotek (diclofenac sodium + misoprostol) dueksis (ibuprofen + famotidine) vimovo (naproxen + esomeprazole) aksorid (ketoprofen + omeprazole) tioaspekard (thiotriazoline + ACK) aspifat (ACK + sucralfate), Alka-Zelttser® (ACK + sodium bicarbonate), and others. The second direction is preventing and improving NSAID gastrotoxicity protrudes improving existing non-steroidal drugs - modification of gaseous molecules (NO, H2S, CO), amino acid derivatives, modulators “effector function” of afferent terminals n. vagus (amtolmetina guatsil) то pairing with nanoparticles biometals (Zn-ibuprofen, Zn-naproxen, Zn-indomethacin). (For citation: Hladkykh FV. Preventive and therapeutic strategies of pharmaco-correction gastropathy induced by nonsteroidal anti-inflammatory drugs. Reviews on Clinical Pharmacology and Drug Therapy. 2017;15(4):14-23. doi: 10.17816/RCF15414-23).

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Ayoub, Zeenat, Archana Mehta und Siddhartha Kumar Mishra. „ETHNOPHARMACOLOGICAL REVIEW OF NATURAL PRODUCTS IN CANCER PREVENTION AND THERAPY“. Asian Journal of Pharmaceutical and Clinical Research 11, Nr. 6 (07.06.2018): 32. http://dx.doi.org/10.22159/ajpcr.2018.v11i6.24792.

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The World Health Organization reports that approximately 80% population from developing countries are facing complications from synthetic drugs used in maintaining their primary health-care needs. The chemotherapeutic strategies are very striking and have earned serious concern as potential means of controlling the incidence of this dreadful disease. However, the major problem in cancer is the long lasting toxicity of the well reputable chemical drugs. Since ancient times, medicinal plants have attracted enormous attention, to fight against various diseases with their broad-spectrum biological and therapeutic properties. Although plants, phytochemicals and their analogues have been confirmed to be safe and effective, having strong anticancer properties. A number of pharmaceutical agents with diverse chemical structures of natural origin from plants have been discovered as anticancer agents such as vincristine, vinblastine, podophyllotoxin, camptothecin, taxol, resveratrol, withaferin A, quercetin, and curcumin. Further modifications of these phytochemicals led to the development of numerous outstanding molecules such as drugs like topotecan, irinotecan, taxotere, etoposide, and teniposide. In this in-depth review, we meticulously investigated the selected medicinal plants for their anticancer properties. In particular, novel compounds from plants have beneficial effects on human health. Our observations suggest the preventive and therapeutic use of phytochemicals in managing various human malignancies.

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Maya-Meraz, Irma Ofelia, José de Jesús Ornelas-Paz, Jaime David Pérez-Martínez, Alfonso A. Gardea-Béjar, Claudio Rios-Velasco, Saúl Ruiz-Cruz, Juan Ornelas-Paz, Ramona Pérez-Leal und José Juan Virgen-Ortiz. „Foliar Application of CaCO3-Rich Industrial Residues on ‘Shiraz’ Vines Improves the Composition of Phenolic Compounds in Grapes and Aged Wine“. Foods 12, Nr. 8 (07.04.2023): 1566. http://dx.doi.org/10.3390/foods12081566.

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The quality of wine grapes and wine depends on their content of phenolic compounds. Under commercial conditions, the phenolic maturity of grapes is mostly achieved by applying abscisic acid analogues. Some Ca forms represent a cost-effective alternative for these compounds. In this study, ‘Shiraz’ vines (veraison of 90%) were sprayed with CaCO3-rich residues from the cement industry (4.26 g of Ca per L). Fruit from treated and untreated vines was harvested 45 days after CaCO3 spraying and evaluated for quality. The fruit was vinified, and the obtained wines were bottled and stored in darkness for 15 months at 20 °C. Wines were evaluated for quality after storage. The evaluation of grape and wine quality included the content of phenolic compounds and antioxidant capacity. The treatment with CaCO3 did not affect the ripening rate of grapes. However, the treatment improved the fruit yield as well as the color development, the content of phenolic compounds, and antioxidant capacity of grapes and wine. The treatment favored especially the accumulation of malvidin-3-O-glucoside, pelargonidin-3-O-glucoside, caftaric acid, caffeic acid, trans-cinnamic acid, quercetin, catechin, epicatechin, resveratrol, and the procyanidins B1 and B2. Wine made with treated fruit was of higher quality than that of control fruit.

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Torres-Piedra, Mariana, Rolffy Ortiz-Andrade, Rafael Villalobos-Molina, Narender Singh, Jose L. Medina-Franco, Scott P. Webster, Margaret Binnie, Gabriel Navarrete-Vázquez und Samuel Estrada-Soto. „A comparative study of flavonoid analogues on streptozotocin–nicotinamide induced diabetic rats: Quercetin as a potential antidiabetic agent acting via 11β-Hydroxysteroid dehydrogenase type 1 inhibition“. European Journal of Medicinal Chemistry 45, Nr. 6 (Juni 2010): 2606–12. http://dx.doi.org/10.1016/j.ejmech.2010.02.049.

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Belchor, Mariana Novo, Caroline Ramos da Cruz Costa, Airam Roggero, Laila L. F. Moraes, Ricardo Samelo, Isabelly Annunciato, Marcos Antonio de Oliveira, Sergio F. Sousa und Marcos Hikari Toyama. „In Silico Evaluation of Quercetin Methylated Derivatives on the Interaction with Secretory Phospholipases A2 from Crotalus durissus terrificus and Bothrops jararacussu“. Pharmaceuticals 16, Nr. 4 (15.04.2023): 597. http://dx.doi.org/10.3390/ph16040597.

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Quercetin derivatives have already shown their anti-inflammatory potential, inhibiting essential enzymes involved in this process. Among diverse pro-inflammatory toxins from snake venoms, phospholipase A2 is one of the most abundant in some species, such as Crotalus durissus terrificus and Bothrops jararacussu from the Viperidae family. These enzymes can induce the inflammatory process through hydrolysis at the sn-2 position of glycerophospholipids. Hence, elucidating the main residues involved in the biological effects of these macromolecules can help to identify potential compounds with inhibitory activity. In silico tools were used in this study to evaluate the potential of quercetin methylated derivatives in the inhibition of bothropstoxin I (BthTX-I) and II (BthTX-II) from Bothrops jararacussu and phospholipase A2 from Crotalus durissus terrificus. The use of a transitional analogous and two classical inhibitors of phospholipase A2 guided this work to find the role of residues involved in the phospholipid anchoring and the subsequent development of the inflammatory process. First, main cavities were studied, revealing the best regions to be inhibited by a compound. Focusing on these regions, molecular docking assays were made to show main interactions between each compound. Results reveal that analogue and inhibitors, Varespladib (Var) and p-bromophenacyl bromide (BPB), guided quercetins derivatives analysis, revealing that Leu2, Phe5, Tyr28, glycine in the calcium-binding loop, His48, Asp49 of BthTX-II and Cdtspla2 were the main residues to be inhibited. 3MQ exhibited great interaction with the active site, similar to Var results, while Q anchored better in the BthTX-II active site. However, strong interactions in the C-terminal region, highlighting His120, seem to be crucial to decreasing contacts with phospholipid and BthTX-II. Hence, quercetin derivatives anchor differently with each toxin and further in vitro and in vivo studies are essential to elucidate these data.

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Riendeau, D., J. P. Falgueyret, J. Guay, N. Ueda und S. Yamamoto. „Pseudoperoxidase activity of 5-lipoxygenase stimulated by potent benzofuranol and N-hydroxyurea inhibitors of the lipoxygenase reaction“. Biochemical Journal 274, Nr. 1 (15.02.1991): 287–92. http://dx.doi.org/10.1042/bj2740287.

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The purified 5-lipoxygenase from porcine leukocytes was found to catalyse the degradation of lipid hydroperoxides in the presence of potent inhibitors of the lipoxygenase reaction. Derivatives of diphenyl-N-hydroxyureas, 4-hydroxybenzofurans and 5-hydroxydihydrobenzofurans all stimulated the 5-lipoxygenase-mediated destruction of 13-hydroperoxyoctadecadienoic acid (13-HPOD). The reaction was dependent on inhibitor and hydroperoxide concentrations (1-10 microM) and could not be detected using heat-inactivated enzyme, when ATP and Ca2+ were omitted or when the hydroperoxide was replaced by the corresponding alcohol. The stability of the inhibitors during this pseudoperoxidase reaction was investigated by measuring the recoveries of 5-hydroxy-2-phenethyl-6-(3-phenoxypropyl)-2,3-dihydrobenzofuran and N-(4-chlorophenyl)-N-hydroxy-N'-(3-chlorophenyl)urea from the reaction mixtures using reverse-phase h.p.l.c. By using an equimolar concentration of 13-HPOD and inhibitor (10 microM) and under conditions where 50% of the 13-HPOD was consumed, the concentration of the benzofuranol decreased by 30%, whereas the N-hydroxyurea derivative could be completely recovered from the reaction mixture. A stimulation of the pseudoperoxidase reaction could be detected only with very effective inhibitors of leukotriene B4 biosynthesis by human leucocytes [IC50 (concn. causing 50% inhibition) less than 100 nM], but not with closely related structural analogues of lower potency or other inhibitors such as nordihydroguaiaretic acid, quercetin or the hydroxamate A-64077. These results demonstrate that 5-lipoxygenase possesses a pseudoperoxidase activity and indicate that potent inhibitors in both N-hydroxyurea and benzofuranol series can function as reducing agents for the enzyme.

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Szydłowska, Iwona, Jolanta Nawrocka-Rutkowska, Agnieszka Brodowska, Aleksandra Marciniak, Andrzej Starczewski und Małgorzata Szczuko. „Dietary Natural Compounds and Vitamins as Potential Cofactors in Uterine Fibroids Growth and Development“. Nutrients 14, Nr. 4 (09.02.2022): 734. http://dx.doi.org/10.3390/nu14040734.

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An analysis of the literature generated within the past 20 year-span concerning risks of uterine fibroids (UFs) occurrence and dietary factors was carried out. A link between Vitamin D deficiency and UFs formation is strongly indicated, making it a potent compound in leiomyoma therapy. Analogs of the 25-hydroxyvitamin D3, not susceptible to degradation by tissue 24-hydroxylase, appear to be especially promising and tend to show better therapeutic results. Although research on the role of Vitamin A in the formation of fibroids is contradictory, Vitamin A-enriched diet, as well as synthetic retinoid analogues, may be preventative or limit the growth of fibroids. Unambiguous conclusions cannot be drawn regarding Vitamin E and C supplementation, except for alpha-tocopherol. Alpha-tocopherol as a phytoestrogen taking part in the modulation of estrogen receptors (ERs) involved in UF etiology, should be particularly avoided in therapy. A diet enriched in fruits and vegetables, as sources of carotenoids, polyphenols, quercetin, and indole-3-carbinol, constitutes an easily modifiable lifestyle element with beneficial results in patients with UFs. Other natural substances, such as curcumin, can reduce the oxidative stress and protect against inflammation in leiomyoma. Although the exact effect of probiotics on uterine fibroids has not yet been thoroughly evaluated at this point, the protective role of dairy products, i.e., yogurt consumption, has been indicated. Trace elements such as selenium can also contribute to antioxidative and anti-inflammatory properties of a recommended diet. In contrast, heavy metals, endocrine disrupting chemicals, cigarette smoking, and a diet low in antioxidants and fiber were, alongside genetic predispositions, associated with UFs formation.

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Kwofie, Samuel K., Kweku S. Enninful, Jaleel A. Yussif, Lina A. Asante, Mavis Adjei, Kwabena Kan-Dapaah, Elvis K. Tiburu et al. „Molecular Informatics Studies of the Iron-Dependent Regulator (ideR) Reveal Potential Novel Anti-Mycobacterium ulcerans Natural Product-Derived Compounds“. Molecules 24, Nr. 12 (21.06.2019): 2299. http://dx.doi.org/10.3390/molecules24122299.

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Buruli ulcer is a neglected tropical disease caused by the bacterium Mycobacterium ulcerans. Its virulence is attributed to the dermo-necrotic polyketide toxin mycolactone, whose synthesis is regressed when its iron acquisition system regulated by the iron-dependent regulator (ideR) is deactivated. Interfering with the activation mechanism of ideR to inhibit the toxin’s synthesis could serve as a possible cure for Buruli ulcer. The three-dimensional structure of the ideR for Mycobacterium ulcerans was generated using homology modeling. A library of 832 African natural products (AfroDB), as well as five known anti-mycobacterial compounds were docked against the metal binding site of the ideR. The area under the curve (AUC) values greater than 0.7 were obtained for the computed Receiver Operating Characteristics (ROC) curves, validating the docking protocol. The identified top hits were pharmacologically profiled using Absorption, Distribution, Metabolism, Elimination and Toxicity (ADMET) predictions and their binding mechanisms were characterized. Four compounds with ZINC IDs ZINC000018185774, ZINC000095485921, ZINC000014417338 and ZINC000005357841 emerged as leads with binding energies of −7.7 kcal/mol, −7.6 kcal/mol, −8.0 kcal/mol and −7.4 kcal/mol, respectively. Induced Fit Docking (IFD) was also performed to account for the protein’s flexibility upon ligand binding and to estimate the best plausible conformation of the complexes. Results obtained from the IFD were consistent with that of the molecular docking with the lead compounds forming interactions with known essential residues and some novel critical residues Thr14, Arg33 and Asp17. A hundred nanoseconds molecular dynamic simulations of the unbound ideR and its complexes with the respective lead compounds revealed changes in the ideR’s conformations induced by ZINC000018185774. Comparison of the lead compounds to reported potent inhibitors by docking them against the DNA-binding domain of the protein also showed the lead compounds to have very close binding affinities to those of the potent inhibitors. Interestingly, structurally similar compounds to ZINC000018185774 and ZINC000014417338, as well as analogues of ZINC000095485921, including quercetin are reported to possess anti-mycobacterial activity. Also, ZINC000005357841 was predicted to possess anti-inflammatory and anti-oxidative activities, which are relevant in Buruli ulcer and iron acquisition mechanisms, respectively. The leads are molecular templates which may serve as essential scaffolds for the design of future anti-mycobacterium ulcerans agents.

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Gejalakshmi, S., und N. Harikrishnan. „Molecular Docking Study of Quercetein Analogues for Treating Tumours“. International Journal of PharmTech Research 12, Nr. 4 (2019): 30–34. http://dx.doi.org/10.20902/ijptr.2019.120405.

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Drug discovery leading to robust and viable lead candidate’s remains a challenging scientific task, which is the transition from a screening hit to a drug candidate, requires expertise and experience. Natural products and their derivatives have been recognized for many years as a source of therapeutic agents and of structural diversity. The present research attempts to describe the utilization of compounds derived from natural resources as drug candidates, with a focus on the success of these resources in the process of finding and discovering new and effective drug compounds, an approach commonly referred to as ―natural product drug discovery

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Gao, Buhong, Yu Sun, Yingchun Miao, Li Xu und Zhongxia Wang. „Fluorometric detection of pH and quercetin based on nitrogen and phosphorus co-doped highly luminescent graphene-analogous flakes“. Analyst 145, Nr. 1 (2020): 115–21. http://dx.doi.org/10.1039/c9an02077b.

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Habtemariam, Solomon. „α-Glucosidase Inhibitory Activity of Kaempferol-3-O-rutinoside“. Natural Product Communications 6, Nr. 2 (Februar 2011): 1934578X1100600. http://dx.doi.org/10.1177/1934578x1100600211.

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Quercetin, kaempferol and to a lesser extent rutin have been reported to have antidiabetic activities when assessed by various assay models including in vitro α-glucosidase inhibition studies. A related structural analogue, kaempferol-3- O-rutinoside (KR) however has not yet been studied for such biological effects. It was found that KR is a potent inhibitor of α-glucosidase in vitro with over 8-times more activity than the reference antidiabetic drug, acarbose. Furthermore, KR displayed a synergistic effect with a less potent flavonoid aglycones, kaempferol and quercetin. The structure-activity profile of these drugs and implications of drug combinations are discussed.

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Nawwar, Mahmoud, Nahla Ayoub, Mohamed El-Raey, Soumaya Zaghloul, Amani Hashem, Eman Mostafa, Omayma Eldahshan, Ulrike Lindequist und Michael W. Linscheid. „Acylated flavonol diglucosides from Ammania auriculata“. Zeitschrift für Naturforschung C 70, Nr. 1-2 (01.01.2015): 39–43. http://dx.doi.org/10.1515/znc-2014-4165.

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Abstract Chemical investigation of the extract of the whole Ammania auriculata plant resulted in the identification of 13 polyphenols, including the hitherto unknown flavonoids, kaempferol 3-O-β-(6″-galloylglucopyranoside)-7-O-β-glucopyranoside, and its quercetin analogue. The structures of all isolates were elucidated by conventional methods, spectroscopic analysis, including 1D and 2D NMR, and by HRESI-MS as well.

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Kamal, M. Vedant, G. Aadarsh Anand und Badal Parekh. „Antimicrobial activity of synthetic quercetin analogue on E. coli and S. aureus“. Journal of Pharmacognosy and Phytochemistry 10, Nr. 5 (01.09.2021): 205–8. http://dx.doi.org/10.22271/phyto.2021.v10.i5c.14199.

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Speisky, Hernán, María Fernanda Arias-Santé und Jocelyn Fuentes. „Oxidation of Quercetin and Kaempferol Markedly Amplifies Their Antioxidant, Cytoprotective, and Anti-Inflammatory Properties“. Antioxidants 12, Nr. 1 (09.01.2023): 155. http://dx.doi.org/10.3390/antiox12010155.

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The contention that flavonoids’ oxidation would necessarily lead to a loss of their antioxidant properties was recently challenged by the demonstration that quercetin oxidation leads to the formation of 2-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Que-BZF), a metabolite whose antioxidant potency was notably higher than that of its precursor. Here, we compared and expanded the former observation to that of the quercetin analogue kaempferol. Oxidation of kaempferol led to the formation of a mixture of metabolites that included the 2-(4-hydroxybenzoyl)-2,4,6-trihydroxy-3(2H)-benzofuranone (Kae-BZF). Following the chromatographic isolation of Kae-BZF from such a mixture, its antioxidant, mitochondria- and cell-protecting, and NF-kB-inhibiting effects were assessed, and compared with those of Que-BZF, in Caco-2 cells exposed to indomethacin as a source of ROS. The concentrations of Que-BZF (100 nm) and Kae-BZF (1 nm) needed to attain their maximal protection effects were 50- and 5000-fold lower than those of their respective precursors. The former differences in concentrations were also seen when the abilities of Que-BZF and Kae-BZF to inhibit the indomethacin-induced activation of NF-kB were compared. These data not only reveal that the oxidative conversion of quercetin and kaempferol into their respective 2-benzoyl-2-hydroxy-3(2H)-benzofuranones (BZF) results in a considerable amplification of their original antioxidant properties, but also that the in the case of kaempferol, such amplification is 100-fold greater than that of quercetin.

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Braune, Annett, Michael Gütschow, Wolfram Engst und Michael Blaut. „Degradation of Quercetin and Luteolin byEubacterium ramulus“. Applied and Environmental Microbiology 67, Nr. 12 (01.12.2001): 5558–67. http://dx.doi.org/10.1128/aem.67.12.5558-5567.2001.

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ABSTRACT The degradation of the flavonol quercetin and the flavone luteolin by Eubacterium ramulus, a strict anaerobe of the human intestinal tract, was studied. Resting cells converted these flavonoids to 3,4-dihydroxyphenylacetic acid and 3-(3,4-dihydroxyphenyl)propionic acid, respectively. The conversion of quercetin was accompanied by the transient formation of two intermediates, one of which was identified as taxifolin based on its specific retention time and UV and mass spectra. The structure of the second intermediate, alphitonin, was additionally elucidated by1H and 13C nuclear magnetic resonance analysis. In resting-cell experiments, taxifolin in turn was converted via alphitonin to 3,4-dihydroxyphenylacetic acid. Alphitonin, which was prepared by enzymatic conversion of taxifolin and subsequent purification, was also transformed to 3,4-dihydroxyphenylacetic acid. The coenzyme-independent isomerization of taxifolin to alphitonin was catalyzed by cell extract or a partially purified enzyme preparation ofE. ramulus. The degradation of luteolin by resting cells of E. ramulus resulted in the formation of the intermediate eriodictyol, which was identified by high-performance liquid chromatography and mass spectrometry analysis. The observed intermediates of quercetin and luteolin conversion suggest that the degradation pathways in E. ramulus start with an analogous reduction step followed by different enzymatic reactions depending on the additional 3-hydroxyl group present in the flavonol structure.

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