Journal articles: 'Flavonoidal oligomers'

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Surbhi, Yadav, and K. Bhadoria B. "Novel biflavonoids from the leaves of Leucaena diversifolia and Albizia procera and their protein binding efficiency." Journal of Indian Chemical Society Vol. 81, May 2004 (2004): 392–94. https://doi.org/10.5281/zenodo.5832967.

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Department of Chemistry, Bipin Bihari College, Jhansi-284 003, India bindian Grassland and Fodder Research Institute, Jhansi-284 003, India E-mail: brijesh@igfri.up.nic.in Manuscript received 22 April 2002, revised 28 August 2003, accepted 2 December 2003 The leaves of Leucαenα diversifoliα and Albiziα procerα have been found to contain two novel biflavonoids, leucaediflavone (1) and albipronavone (2) which were characterized as (5,2',3' -trihydroxy-5',6' -furano-7.,8-dimethylallyloxy)-(5,3' -dihydroxy5' ,6' -furano-7,8-dimethylallyloxy)-6C -2' -biflavonyl and bis[5,3' ,4' -trihydroxy-2' -hydroxymethyl-5' ,6' -furano-8,7 -(3- hydroxyphenyi]-6C-6-billavonyl, respectively on the basis of spectral (UV, IR, MS, ID and 2D NMR) evidences. Both showed protein binding efficiency 201.81and 253.05µg BSA/mg respectively.

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Matos, Ana M., Joana S. Cristóvão, Dmitry V. Yashunsky та ін. "Synthesis and effects of flavonoid structure variation on amyloid-β aggregation". Pure and Applied Chemistry 89, № 9 (2017): 1305–20. http://dx.doi.org/10.1515/pac-2017-0201.

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AbstractDietary flavonoids and synthetic derivatives have a well-known potential for biomedical applications. In this perspective, we report herein new methodologies to access chrysin and 5,7-dihydroxychromone, and these structures were combined with those of naturally occurring quercetin, luteolin, (+)-dihydroquercetin and apigenin to assemble a set of polyphenols with structure variations for in vitro testing over the aggregation of Alzheimer’s disease (AD) amyloid peptide Aβ1−42. Using thioflavin-T (ThT) monitored kinetics and subsequent mechanistic analysis by curve fitting, we show that catechol-type flavonoids reduce Aβ1−42 fibril content by 30% at molar ratios over 10. Without affecting secondary nucleation, these compounds accelerate primary nucleation events responsible for early primary oligomer formation, putatively redirecting the latter into off-pathway aggregates. Atomic force microscopy (AFM) imaging of reaction end-points allowed a comprehensive topographical analysis of amyloid aggregate populations formed in the presence of each compound. Formation of Aβ1−42 small oligomers, regarded as the most toxic amyloid structures, seems to be limited by flavonoids with a C2 phenyl group, while flavonol 3-OH is not a beneficial structural feature. Overall, the diversity of structural variations within flavonoids opens avenues for their development as chemical tools in the treatment of AD by tackling the formation and distribution of neurotoxic oligomers species.

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Fedorova, Tat'yana Yevgen'yevna, Sergey Vladimirovich Fedorov, and Vasily Anatolyevich Babkin. "PHENOLIC COMPOUNDS OF CEDAR WOOD (SIBERIAN PINE) PINUS SIBIRICA DU TOUR." chemistry of plant raw material, no. 3 (October 22, 2020): 97–104. http://dx.doi.org/10.14258/jcprm.2020037329.

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As part of the study of extractives of biomass of coniferous trees of Siberia in order to predict the possibility of obtaining valuable biologically active products, a study was conducted of the chemical composition of the ethyl acetate extract of cedar wood (Siberian pine) Pinus sibirica Du Tour. The chemical composition of the phenolic compounds of cedar wood was studied, including the structure of oligomeric polyphenols.  The yields of extractives extracted with ethyl acetate and water from cedar wood were 1.6 and 2.71% of a.s. (absolutely dry matter). The content of phenolic compounds in the ethyl acetate extract of cedar wood was 45.9% rel. Based on 1H and 13C NMR spectroscopy data, it was found that the main monomeric phenolic extractive substances of cedar wood are stilbene – pinosilvin monomethyl ether (content in cedar wood 0.25% of a.s.) and flavonoids – tectochrizin, pinocembrin, and pinobankxin, as well as oligomeric and polymeric phenolic compounds. It was shown that the composition of cedar wood oligomers includes a complex mixture of stilbene derivatives of pinosilvin and flavonoids with the inclusion of carbohydrate residues. The content of the fraction of oligomeric and polymeric phenolic compounds in cedar wood is 0.39% of a.s.

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Muñiz-Mouro, Abel, Beatriz Gullón, Thelmo Lú-Chau, María Moreira, Juan Lema, and Gemma Eibes. "Laccase Activity as an Essential Factor in the Oligomerization of Rutin." Catalysts 8, no. 8 (2018): 321. http://dx.doi.org/10.3390/catal8080321.

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The enzyme-mediated polymerization of bioactive phenolic compounds, such as the flavonoid rutin, has gained interest due to the enhanced physico-chemical and biological properties of the products, which increases their potential application as a nutraceutical. In this work, the influence of enzyme activity on rutin oligomerization was evaluated in reactions with low (1000 U/L) and high (10,000 U/L) initial laccase activities. For both reactions, high molecular weight oligomer fractions showed better properties compared to lower weight oligomers. Products of the reaction with low laccase activity exhibited thermal stability and antioxidant potential similar to control reaction, but led to higher inhibitory activity of xanthine oxidase and apparent aqueous solubility. Oligomers obtained in the reaction with high laccase activity showed better apparent aqueous solubility but decreased biological activities and stability. Their low antioxidant activity was correlated with a decreased phenolic content, which could be attributed to the formation of several bonds between rutin molecules.

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Donovan, Jennifer L., Adam Lee, Claudine Manach, et al. "Procyanidins are not bioavailable in rats fed a single meal containing a grapeseed extract or the procyanidin dimer B3." British Journal of Nutrition 87, no. 4 (2002): 299–306. http://dx.doi.org/10.1079/bjn2001517.

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Flavanols are the most abundant flavonoids in the human diet where they exist as monomers, oligomers and polymers. In the present study, catechin, the procyanidin dimer B3 and a grapeseed extract containing catechin, epicatechin and a mixture of procyanidins were fed to rats in a single meal. After the meals, catechin and epicatechin were present in conjugated forms in both plasma and urine. In contrast, no procyanidins or conjugates were detected in the plasma or urine of any rats. Procyanidins were not cleaved into bioavailable monomers and had no significant effects on the plasma levels or urinary excretion of the monomers when supplied together in the grapeseed extract. We conclude that the nutritional effects of dietary procyanidins are unlikely to be due to procyanidins themselves or monomeric metabolites with the intact flavonoid-ring structure, as they do not exist at detectable concentrations in vivo. Future research should focus on other procyanidin metabolites such as phenolic acids and on the effects of the unabsorbed oligomers and polymers on the human gastrointestinal tract.

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Oliver, Susan, James M. Hook, and Cyrille Boyer. "Versatile oligomers and polymers from flavonoids – a new approach to synthesis." Polymer Chemistry 8, no. 15 (2017): 2317–26. http://dx.doi.org/10.1039/c7py00325k.

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Zhu, Qin Yan, Derek D. Schramm, Heidrun B. Gross, et al. "Influence of Cocoa Flavanols and Procyanidins on Free Radical-induced Human Erythrocyte Hemolysis." Clinical and Developmental Immunology 12, no. 1 (2005): 27–34. http://dx.doi.org/10.1080/17402520512331329514.

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Cocoa can be a rich source of antioxidants including the flavan-3-ols, epicatechin and catechin, and their oligomers (procyanidins). While these flavonoids have been reported to reduce the rate of free radical-induced erythrocyte hemolysis in experimental animal models, little is known about their effect on human erythrocyte hemolysis. The major objective of this work was to study the effect of a flavonoid-rich cocoa beverage on the resistance of human erythrocytes to oxidative stress. A second objective was to assess the effects of select purified cocoa flavonoids, epicatechin, catechin, the procyanidin Dimer B2 and one of its major metabolites, 3ʹ-O-methyl epicatechin, on free radical-induced erythrocyte hemolysisin vitro. Peripheral blood was obtained from 8 healthy subjects before and 1, 2, 4 and 8 h after consuming a flavonoid-rich cocoa beverage that provided 0.25 g/kg body weight (BW), 0.375 or 0.50 g/kg BW of cocoa. Plasma flavanol and dimer concentrations were determined for each subject. Erythrocyte hemolysis was evaluated using a controlled peroxidation reaction. Epicatechin, catechin, 3ʹ-O-methyl epicatechin and (-)-epicatechin-(4β > 8)epicatechin (Dimer B2) were detected in the plasma within 1 h after the consumption of the beverage. The susceptibility of erythrocytes to hemolysis was reduced significantly following the consumption of the beverages. The duration of the lag time, which reflects the capacity of cells to buffer free radicals, was increased. Consistent with the above, the purified flavonoids, epicatechin, catechin, Dimer B2 and the metabolite 3ʹ-O-methyl epicatechin, exhibited dose-dependent protection against AAPH-induced erythrocyte hemolysis at concentrations ranging from 2.5 to 20 μM. Erythrocytes from subjects consuming flavonoid-rich cocoa show reduced susceptibility to free radical-induced hemolysis (p< 0.05).

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Xiong, Qiangqiang, Han Wu, Runnan Wang, Siqi Tang, and Haihua Luo. "Exogenous Trilobatin Enhances Flavonoid Content in Purple Rice Grains and Affects the Flavonoid Biosynthesis Pathway." Plants 13, no. 23 (2024): 3389. https://doi.org/10.3390/plants13233389.

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Antioxidant activity and flavonoid content are important characteristics of colored rice grains. Previously, we obtained a preliminary understanding of the metabolic markers of antioxidant activity, namely, phlorizin and trilobatin, in different colored rice varieties and purple rice grains at different growth stages, but the mechanisms associated with these markers have not yet been confirmed. In this study, purple rice was selected as the experimental material, and clover extract was applied during the grain-filling stage to explore the impact of clover extract on the total antioxidant capacity and flavonoid biosynthesis in purple rice grains. The results indicated that the total flavonoid content, total phenolic content, oligomeric proanthocyanidin content, and total antioxidant capacity of purple rice grains treated with an exogenous application of trilobatin (T30) were significantly greater than those of the control (CK). The flavonoids in the T30 and CK groups accounted for 29.81% of the total flavonoids. The phenylpropanoid biosynthesis and flavonoid biosynthesis metabolic pathways were constructed on the basis of the differentially abundant metabolites between the T30 and CK groups. Additionally, 1-O-sinapoyl-beta-D-glucose, coniferaldehyde, 6″-acetylapiin, and kaempferol-3-O-rutinoside were determined to be essential metabolites for trilobatin-mediated flavonoid biosynthesis in purple rice. The correlation network diagram between biochemical indexes and metabolites revealed that 1-O-sinapoyl-beta-D-glucose, coniferaldehyde, 6″-acetylapiin, and kaempferol-3-O-rutinoside were important metabolites. This study provides a scientific basis for improving the nutritional quality of rice grains and understanding the flavonoid biosynthesis pathway.

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Shen, Chuan-Pu, Jian-Guang Luo, Ming-Hua Yang, and Ling-Yi Kong. "Anticoagulant flavonoid oligomers from the rhizomes of Alpinia platychilus." Fitoterapia 106 (October 2015): 153–57. http://dx.doi.org/10.1016/j.fitote.2015.09.010.

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Thilakarathna, Wasitha P. D. W., and H. P. Vasantha Rupasinghe. "Proanthocyanidins-Based Synbiotics as a Novel Strategy for Nonalcoholic Fatty Liver Disease (NAFLD) Risk Reduction." Molecules 29, no. 3 (2024): 709. http://dx.doi.org/10.3390/molecules29030709.

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Nonalcoholic fatty liver disease (NAFLD), the most common liver disease worldwide, is a spectrum of liver abnormalities ranging from steatosis to nonalcoholic steatohepatitis (NASH) characterized by excessive lipid accumulation. The prevalence of NAFLD is predicted to increase rapidly, demanding novel approaches to reduce the global NAFLD burden. Flavonoids, the most abundant dietary polyphenols, can reduce the risk of NAFLD. The majority of dietary flavonoids are proanthocyanidins (PACs), which are oligomers and polymers of the flavonoid sub-group flavan-3-ols. The efficacy of PAC in reducing the NAFLD risk can be significantly hindered by low bioavailability. The development of synbiotics by combining PAC with probiotics may increase effectiveness against NAFLD by biotransforming PAC into bioavailable metabolites. PAC and probiotic bacteria are capable of mitigating steatosis primarily through suppressing de novo lipogenesis and promoting fatty acid β-oxidation. PAC and probiotic bacteria can reduce the progression of steatosis to NASH mainly through ameliorating hepatic damage and inflammation induced by hepatic oxidative stress, endoplasmic reticulum stress, and gut microbiota dysbiosis. Synbiotics of PAC are superior in reducing the risk of NAFLD compared to independent administration of PAC and probiotics. The development of PAC-based synbiotics can be a novel strategy to mitigate the increasing incidence of NAFLD.

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Merlin Jayalal, L. P. "Bi-flavonoids are Superior to Mono-flavonoid in Inhibiting Amyloid-${\beta}$ Toxicity and Fibrillogenesis through Accumulating Nontoxic Oligomer-like Structures." Journal of the Chosun Natural Science 5, no. 2 (2012): 107–19. http://dx.doi.org/10.13160/ricns.2012.5.2.107.

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Lee, Mi-Jin, Miey Park, and Hae-Jeung Lee. "Dietary Supplemented Anthocyanin Reduced Serum Amyloid Beta Oligomers and Improved Cognitive Dysfunction Scores in Elderly Dogs." Applied Sciences 12, no. 23 (2022): 12130. http://dx.doi.org/10.3390/app122312130.

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Like humans, the accumulation of amyloid-beta oligomers in the brains of aged dogs leads to cognitive dysfunction. Our study investigated the effects of dietary flavonoids in pet foods on cognitive dysfunction. All nine dogs (six species) recruited were older than seven years, and cognitive function was measured using a questionnaire before and after applying pet food containing cyanidin-3-O-glucoside, the main component of honeyberries. Physical examination, blood tests, cognitive dysfunction scores, and serum amyloid-beta oligomers were measured. After 90 days of pet food administration, a physical examination revealed no abnormalities in weight, body temperature, heart rate, or respiratory rate. However, the cognitive dysfunction score and serum amyloid-beta oligomers (AβO) marker levels were significantly reduced after 90 days. Inflammation and antioxidant levels were slightly, but not significantly, changed. Our results suggest that pet food containing anthocyanins effectively improves cognitive dysfunction scores and decreases serum AβO levels.

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Labois, Clément, Kim Wilhelm, Hélène Laloue, et al. "Wood Metabolomic Responses of Wild and Cultivated Grapevine to Infection with Neofusicoccum parvum, a Trunk Disease Pathogen." Metabolites 10, no. 6 (2020): 232. http://dx.doi.org/10.3390/metabo10060232.

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Grapevine trunk diseases (GTDs), which are associated with complex of xylem-inhabiting fungi, represent one of the major threats to vineyard sustainability currently. Botryosphaeria dieback, one of the major GTDs, is associated with wood colonization by Botryosphaeriaceae fungi, especially Neofusicoccum parvum. We used GC-MS and HPLC-MS to compare the wood metabolomic responses of the susceptible Vitis vinifera subsp. vinifera (V. v. subsp. vinifera) and the tolerant Vitis vinifera subsp. sylvestris (V. v. subsp. sylvestris) after artificial inoculation with Neofusicoccum parvum (N. parvum). N. parvum inoculation triggered major changes in both primary and specialized metabolites in the wood. In both subspecies, infection resulted in a strong decrease in sugars (fructose, glucose, sucrose), whereas sugar alcohol content (mannitol and arabitol) was enhanced. Concerning amino acids, N. parvum early infection triggered a decrease in aspartic acid, serine, and asparagine, and a strong increase in alanine and β-alanine. A trend for more intense primary metabolism alteration was observed in V. v. subsp. sylvestris compared to V. v. subsp. vinifera. N. parvum infection also triggered major changes in stilbene and flavonoid compounds. The content in resveratrol and several resveratrol oligomers increased in the wood of both subspecies after infection. Interestingly, we found a higher induction of resveratrol oligomer (putative E-miyabenol C, vitisin C, hopeaphenol, ampelopsin C) contents after wood inoculation in V. v. subsp. sylvestris.

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Chervyakovsky, E. M., D. A. Bolibrukh, D. L. Kurovskii, et al. "Oligomeric oxidation products of the flavonoid quercetin." Chemistry of Natural Compounds 44, no. 4 (2008): 427–31. http://dx.doi.org/10.1007/s10600-008-9092-1.

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Bocian, Wojciech, Robert Kawęcki, Elżbieta Bednarek, Jerzy Sitkowski, Agnieszka Ulkowska, and Lech Kozerski. "Interaction of flavonoid topoisomerase I and II inhibitors with DNA oligomers." New Journal of Chemistry 30, no. 3 (2006): 467. http://dx.doi.org/10.1039/b517245b.

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Hong, Dong-Pyo, Anthony L. Fink та Vladimir N. Uversky. "Structural Characteristics of α-Synuclein Oligomers Stabilized by the Flavonoid Baicalein". Journal of Molecular Biology 383, № 1 (2008): 214–23. http://dx.doi.org/10.1016/j.jmb.2008.08.039.

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SASAKI, KENROH, SYUKO CHIBA, and FUMIHIKO YOSHIZAKI. "Effect of natural flavonoids, stilbenes and caffeic acid oligomers on protein glycation." Biomedical Reports 2, no. 5 (2014): 628–32. http://dx.doi.org/10.3892/br.2014.304.

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Li, Liya, Geneive E. Henry, and Navindra P. Seeram. "Identification and Bioactivities of Resveratrol Oligomers and Flavonoids from Carex folliculata Seeds." Journal of Agricultural and Food Chemistry 57, no. 16 (2009): 7282–87. http://dx.doi.org/10.1021/jf901716j.

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Uemori, Haruna, Ayano Inoue, Shoichi Suzuki, et al. "Ellagitannin Oligomers from Eucalyptus camaldulensis Leaves and Their Role in the Detoxification of Aluminum." Molecules 30, no. 10 (2025): 2216. https://doi.org/10.3390/molecules30102216.

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Eucalyptus camaldulensis of the Myrtaceae family shows high resistance to aluminum (Al) ions and contains various compounds such as steroids, terpenoids, saponins, flavonoids, glycosides, alkaloids, and tannins. Although the ellagitannin oenothein B (12) isolated from E. camaldulensis exhibits remarkable properties for Al detoxification, likely contributing to its Al resistance, other ellagitannin oligomers present in E. camaldulensis have not been investigated in detail. In this study, novel dimeric and trimeric ellagitannin oligomers eucarpanin D2 (1) and eucamalin A (2), together with known gallotannins (7, 8, and 10), monomeric ellagitannins (4–6, and 11), and dimeric ellagitannins (3, 9, and 12–14), were isolated from E. camaldulensis leaves. The structures of these novel compounds were elucidated based on their chemical and physicochemical properties, including the orientations of tergalloyl groups in compounds 1 and 2. Similar to compound 12, previously isolated from the roots of E. camaldulensis, the ellagitannins demonstrated good Al detoxification properties. Hence, these tannins may play a critical role in the high Al resistance of E. camaldulensis in acidic soils. This paper reports for the first time the isolation of ellagitannin oligomers from the leaves of E. camaldulensis.

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Latos-Brozio, Malgorzata, Anna Masek, and Małgorzata Piotrowska. "Polymeric Forms of Plant Flavonoids Obtained by Enzymatic Reactions." Molecules 27, no. 12 (2022): 3702. http://dx.doi.org/10.3390/molecules27123702.

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Naringenin is one of the flavonoids originating from citrus fruit. This polyphenol is mainly found in grapefruit, orange and lemon. The antioxidant and antimicrobial properties of flavonoids depend on their structure, including the polymeric form. The aim of this research was to achieve enzymatic polymerization of naringenin and to study the properties of poly(naringenin). The polymerization was performed by methods using two different enzymes, i.e., laccase and horseradish peroxidase (HRP). According to the literature data, naringenin had not been polymerized previously using the enzymatic polymerization method. Therefore, obtaining polymeric naringenin by reaction with enzymes is a scientific novelty. The research methodology included analysis of the structure of poly(naringenin) by NMR, GPC, FTIR and UV-Vis and its morphology by SEM, as well as analysis of its properties, i.e., thermal stability (DSC and TGA), antioxidant activity (ABTS, DPPH, FRAP and CUPRAC) and antimicrobial properties. Naringenin oligomers were obtained as a result of polymerization with two types of enzymes. The polymeric forms of naringenin were more resistant to thermo-oxidation; the final oxidation temperature To of naringenin catalyzed by laccase (poly(naringenin)-laccase) was 28.2 °C higher, and poly(naringenin)-HRP 23.6 °C higher than that of the basic flavonoid. Additionally, due to the higher molar mass and associated increase in OH groups in the structure, naringenin catalyzed by laccase (poly(naringenin)-laccase) showed better activity for scavenging ABTS+• radicals than naringenin catalyzed by HRP (poly(naringenin)-HRP) and naringenin. In addition, poly(naringenin)-laccase at a concentration of 5 mg/mL exhibited better microbial activity against E. coli than monomeric naringenin.

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Zheng, Qing-An, Min Xu, Chong-Ren Yang, et al. "Flavonoid oligomers from Chinese dragon’s blood, the red resins of Dracaena cochinchinensis." Natural Products and Bioprospecting 2, no. 3 (2012): 111–16. http://dx.doi.org/10.1007/s13659-012-0020-5.

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Kandil, F. E., L. Song, J. M. Pezzuto, K. Marley, D. S. Seigler, and M. A. L. Smith. "Isolation of oligomeric proanthocyanidins from flavonoid-producing cell cultures." In Vitro Cellular & Developmental Biology - Plant 36, no. 6 (2000): 492–500. http://dx.doi.org/10.1007/s11627-000-0088-1.

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Gruber, Margaret, Birgitte Skadhauge, Min Yu, Alister Muir, and Kenneth Richards. "Variation in morphology, plant habit, proanthocyanidins, and flavonoids within a Lottus germplasm collection." Canadian Journal of Plant Science 88, no. 1 (2008): 121–32. http://dx.doi.org/10.4141/p06-158.

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Lotus species collec ted from a range of geographical locations were evaluated for relationships between plant habit and size, leaf proanthocyanidin (PA) content, flower colour, stem colour, leaf colour, trichome density, and geographic origin. No relationships occurred between leaf PA concentration and morphological trait or collection site. Trichome coverage was moderately correlated with plant size (r = -0.70). Several accessions, e.g., L. angustissimus L. and L. castellanis Boiss. & Reut., consisted of small, trichome-covered plants distinct from the large, glabrous plants typical of the model species L. corniculatus var. japonicus ecotype Gifu B129. These two morphology types were also represented among the tan mutants of Gifu B129. Due to the importance of trichomes and PA in plant defence, PA composition was compared between L. angustissimusand tan1 (both representing the small trichome-covered phenotype) and ecotype Gifu B129 and tan2 (both representing the large, glabrous phenotype). Both the tan1 and tan2 mutants accumulated substantial amounts of leaf PA similar in size to the small oligomers recovered from leaves of L. angustissimus. PA polymers were undetectable in Gifu B129 leaves, while floral PA extracts of this ecotype included a much larger PA polymer. Flavonoid composition in leaves of tan1 and L. angustissimus was complex, and differed from the simple profile in Gifu B129 leaves. Key words: Lotus, proanthocyanidin, flavonoids, trichomes, morphology, plant habit, variability

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Hao, Qian, Yoshinori Saito, Yosuke Matsuo, Hai-Zhou Li, and Takashi Tanaka. "Chalcane-stilbene conjugates and oligomeric flavonoids from Chinese Dragon's Blood produced from Dracaena cochinchinensis." Phytochemistry 119 (November 30, 2015): 76–82. https://doi.org/10.1016/j.phytochem.2015.09.009.

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Hao, Qian, Saito, Yoshinori, Matsuo, Yosuke, Li, Hai-Zhou, Tanaka, Takashi (2015): Chalcane-stilbene conjugates and oligomeric flavonoids from Chinese Dragon's Blood produced from Dracaena cochinchinensis. Phytochemistry 119: 76-82, DOI: 10.1016/j.phytochem.2015.09.009, URL: http://dx.doi.org/10.1016/j.phytochem.2015.09.009

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Lacatusu, Ioana, Nicoleta Maria Badea, and Aurelia Meghea. "Effect of Surfactants on Stability of Colloidal Sols as Precursors in Sol-Gel Encapsulation." Key Engineering Materials 415 (September 2009): 57–60. http://dx.doi.org/10.4028/www.scientific.net/kem.415.57.

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This paper aims to study the effect of three alkyl quaternary salts on stability of colloidal sols further used as water-insoluble oligomers for encapsulation of an active flavonoid compound – quercitin. The preparation procedure is described and practical remarks on silica-based sol-gels are included. It is also demonstrated how to exploit the sol-gel preparation route in order to improve the thermal resistance of quercitin and to increase an optical function - fluorescence. The evolution in time of competitive hydrolysis and condensation processes has been observed by dynamic light scattering measurements. The sol-gel materials with entrapped quercitin molecule have been characterised by spectral methods (FT-IR, UV-VIS-NIR), fluorescence and by thermal analysis as well. Sol-gel materials doped with active flavonoid compound may be used in preparation of some functional materials with bioactive properties.

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Zhytniakivska, Olha, Tanmay Chaturvedi, and Mette Hedegaard Thomsen. "Plant-Based Inhibitors of Protein Aggregation." Biomolecules 15, no. 4 (2025): 481. https://doi.org/10.3390/biom15040481.

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The assembly of amyloidogenic proteins and peptides into toxic oligomeric and fibrillar aggregates is closely connected to the onset and progression of more than 50 protein diseases, such as Alzheimer’s disease, Parkinson’s disease, prion disease, and type 2 diabetes, to name only a few. Considerable research efforts at identifying the therapeutic strategies against these maladies are currently focused on preventing and inhibiting pathogenic protein aggregation by various agents. Plant-based extracts and compounds have emerged as promising sources of potential inhibitors due to their dual role as nutraceuticals as part of healthy diets and as specific pharmaceuticals when administered at higher concentrations. In recent decades, several plant extracts and plant-extracted compounds have shown potential to modulate protein aggregation. An ever-growing body of research on plant-based amyloid inhibitors requires a detail analysis of existing data to identify potential knowledge gaps. This review summarizes the recent progress in amyloid inhibition using 17 flavonoids, 11 polyphenolic non-flavonoid compounds, 23 non-phenolic inhibitors, and 59 plant extracts, with the main emphasis on directly modulating the fibrillation of four amyloid proteins, namely amyloid-β peptide, microtubule-associated protein tau, α-synuclein, and human islet amyloid polypeptide.

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Cao-Ngoc, Phu, Laurent Leclercq, Jean-Christophe Rossi, et al. "Water-Based Extraction of Bioactive Principles from Blackcurrant Leaves and Chrysanthellum americanum: A Comparative Study." Foods 9, no. 10 (2020): 1478. http://dx.doi.org/10.3390/foods9101478.

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The water-based extraction of bioactive components from flavonoid-rich medicinal plants is a key step that should be better investigated. This is especially true when dealing with easy-to-use home-made conditions of extractions, which are known to be a bottleneck in the course for a better control and optimization of the daily uptake of active components from medicinal plants. In this work, the water-based extraction of Blackcurrant (Ribes nigrum) leaves (BC) and Chrysanthellum americanum (CA), known to have complementary pharmacological properties, was studied and compared with a previous work performed on the extraction of Hawthorn (Crataegus, HAW). Various extraction modes in water (infusion, percolation, maceration, ultrasounds, microwaves) were compared for the extraction of bioactive principles contained in BC and CA in terms of extraction yield, of amount of flavonoids, phenolic compounds, and proanthocyanidin oligomers, and of UHPLC profiles of the extracted compounds. The qualitative and quantitative aspects of the extraction, in addition to the kinetic of extraction, were studied. The optimized easy-to-use-at-home extraction protocol developed for HAW was found very efficient to easily extract bioactive components from BC and CA plants. UHPLC-ESI-MS and high-resolution Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) were also implemented to get more qualitative information on the specific and common chemical compositions of the three plants (including HAW). Their antihyaluronidase, antioxidant, and antihypertensive activities were also determined and compared, demonstrating similar activities as the reference compound for some of these plants.

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Merlin Jayalal, L. P. "Competitive Superiority by Bi-flavonoids to Mono-flavonoids in Inhibiting Amyloid-β Toxicity and Fibrillogenesis through Accumulating Nontoxic Oligomer-like Structures". Journal of the Chosun Natrural Science 6, № 2 (2013): 87–99. http://dx.doi.org/10.13160/ricns.2013.6.2.87.

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Sun, Shimeng, Qing Ma, Qiyu Sheng та ін. "Amyloid-β Oligomer-Induced Electrophysiological Mechanisms and Electrical Impedance Changes in Neurons". Sensors 24, № 4 (2024): 1211. http://dx.doi.org/10.3390/s24041211.

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Amyloid plays a critical role in the pathogenesis of Alzheimer’s disease (AD) and can aggregate to form oligomers and fibrils in the brain. There is increasing evidence that highly toxic amyloid-β oligomers (AβOs) lead to tau protein aggregation, hyperphosphorylation, neuroinflammation, neuronal loss, synaptic loss, and dysfunction. Although the effects of AβOs on neurons have been investigated using conventional biochemical experiments, there are no established criteria for electrical evaluation. To this end, we explored electrophysiological changes in mouse hippocampal neurons (HT22) following exposure to AβOs and/or naringenin (Nar, a flavonoid compound) using electrical impedance spectroscopy (EIS). AβO-induced HT22 showed a decreased impedance amplitude and increased phase angle, and the addition of Nar reversed these changes. The characteristic frequency was markedly increased with AβO exposure, which was also reversed by Nar. The AβOs decreased intranuclear and cytoplasmic resistance and increased nucleus resistance and extracellular capacitance. Overall, the innovative construction of the eight-element CPE-equivalent circuit model further reflects that the pseudo-capacitance of the cell membrane and cell nucleus was increased in the AβO-induced group. This study conclusively revealed that AβOs induce cytotoxic effects by disrupting the resistance characteristics of unit membranes. The results further support that EIS is an effective technique for evaluating AβO-induced neuronal damage and microscopic electrical distinctions in the sub-microscopic structure of reactive cells.

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Wang, Hongtao, Ping Lu, Zhiqiang Li, et al. "Oligomeric Proanthocyanidins and Bamboo Leaf Flavonoids Improve the Quality of Bull Semen Cryopreservation." Molecules 27, no. 3 (2022): 1144. http://dx.doi.org/10.3390/molecules27031144.

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It is important to inhibit oxidative stress to maintain sperm motility during cryopreservation. The present study was performed to investigate the effects of supplementing oligomeric proanthocyanidins (OPC) and bamboo leaf flavonoids (BLF) or their combination as an extender for Simmental bull semen freezing. OPC, BLF, or their combination were added to the frozen diluent of bovine semen. Afterwards, computer-assisted semen analysis (CASA), detection of membrane functionality, acrosome integrity, mitochondrial integrity, CAT, SOD, GSH-PX, MDA, and ROS were conducted. The results showed that adding 50 mg/L OPC or 4 mg/L BLF could improve the quality of frozen sperm. Compared with 50 mg/L OPC alone, the combination of 50mg/L OPC and 2 mg/L BLF significantly increased the kinematic parameters of sperm, and sperm CAT, GSH-PX and SOD levels (p < 0.05), whereas the MDA of sperm was decreased (p < 0.05). These results indicated that compared to the addition of 50 mg/L OPC alone, a combination of 50 mg/L OPC and 2 mg/L BLF could further improve the quality of frozen semen. The results could provide theoretical data support for the development of a new protective agent and are significant for the cryopreservation of bovine semen in the future.

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Abdelwahed, A., W. Bhouri, A. Neffati, et al. "Antigenotoxic and Antioxidant Activities of Fruit Extracts from (Tunisian) Pistacia Lentiscus." Food Science and Technology International 15, no. 3 (2009): 215–22. http://dx.doi.org/10.1177/1082013208339705.

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Genotoxic and antigenotoxic activities against direct acting mutagen nifuroxazide, and indirect acting genotoxin aflatoxine B1 (AFB1) of extracts prepared from fruits of Pistacia lentiscus, were studied using the SOS chromotest with Escherichia coli PQ 37 as a tester organism. It was found that different extracts showed no genotoxicity when tested with E. coli PQ 37 strain either with or without microsomal extract. On the other hand, our results showed that ethyl acetate fraction and total oligomers flavonoids (TOF) extract obtained from P. lentiscus significantly decreased the genotoxicicity induced by AFB1 (10 μg/assay) and nifuroxazide (20 μg/assay). In addition to antigenotoxic activity, these extracts showed an important free radical scavenging activity towards the 2,2-diphenyl-2-picrylhydrazyl (DPPH) free radical and an important antioxidant activity using xanthine/xanthine oxidase system.

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Trabelsi, Amine, Mohamed Amine El Kaibi, Aïmen Abbassi, Amira Horchani, Leila Chekir-Ghedira, and Kamel Ghedira. "Phytochemical Study and Antibacterial and Antibiotic Modulation Activity of Punica granatum (Pomegranate) Leaves." Scientifica 2020 (March 31, 2020): 1–7. http://dx.doi.org/10.1155/2020/8271203.

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This study aimed to determine phytochemical contents, antibacterial properties, and antibiotic modulating potential of Punica granatum leaf extracts: hexane, chloroform, ethyl acetate, ethanol, and aqueous extracts as well as an extract enriched with total oligomer flavonoids (TOFs). The TOF extract contained the highest value of phenols and flavonoids. Rutin, luteolin, gallic acid, and ellagic acid were determined by HPLC analysis of this extract. The antibacterial activity was assayed by the disc diffusion method and microdilution method against Staphylococcus aureus and Escherichia coli standard ATCC strains and clinical isolates resistant strains. The TOF extract was the most active against all tested strains. The checkerboard method was used for the determination of synergy between two antibiotics (amoxicillin and cefotaxime) and P. granatum leaf extracts. The best synergistic interaction was found with TOF extract combined with amoxicillin for penicillin-resistant E. coli and penicillin-resistant S. aureus. These results can be assigned to tannins, flavonoids, and phenolic acids found in P. granatum leaf extracts. Pomegranate leaf extracts or active compounds isolated from these extracts could be used to fight the emergence and spread of resistant bacterial strains.

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Gevrenova, Reneta, Anna Szakiel, Cezary Pączkowski, et al. "Erica spiculifolia Salisb. (Balkan Heath): A Focus on Metabolic Profiling and Antioxidant and Enzyme Inhibitory Properties." Plants 14, no. 11 (2025): 1648. https://doi.org/10.3390/plants14111648.

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Erica spiculifolia Salisb. (formerly Bruckenthalia spiculifolia Benth.) (Balkan heath) is renowned for its traditional usage as a diuretic, anti-inflammatory and antioxidant agent. For the first time, acylquinic acids, flavonoids and numerous proanthocyanidin oligomers were annotated/dereplicated by liquid chromatography–high-resolution mass spectrometry in methanol–aqueous extracts from E. spiculifolia aerial parts harvested at the early and full flowering stage. Chlorogenic acid and proanthocyanidin tetra- and trimer A, B-type together with quercitrin and (+) catechin were the predominant compounds in the semi-quantitative analysis. Neutral triterpenoids, triterpenoid acids and phytosterols were determined in apolar extracts by gas chromatography–mass spectrometry. Triterpenoid acids accounted for 80% of the total triterpenoid content, dominated by ursolic and oleanolic acid, reaching up to 32.2 and 6.1 mg/g dw, respectively. Ursa/olean-2,12-dien-28-oic acids and 3-keto-derivatives together with α-amyrin acetate as a chemotaxonomic marker, α-amyrenone, α- and β-amyrin were evaluated. Total phenolic and flavonoid contents were 83.85 ± 0.89 mg gallic acid equivalents/g and 78.91 ± 0.41 mg rutin equivalents/g, respectively. The extract actively scavenged DPPH and ABTS radicals (540.01 and 639.11 mg Trolox equivalents (TE)/g), possessed high potential to reduce copper and iron ions (660.32 and 869.22 mg TE/g, respectively), and demonstrated high metal chelating capacity (15.57 Ethylenediaminetetraacetic acid equivalents/g). It exhibited prominent anti-lipase (18.32 mg orlistat equivalents/g) and anti-tyrosinase (71.90 mg kojic acid equivalents/g) activity. The extract inhibited α-glucoside (1.35 mmol acarbose equivalents/g) and acetylcholinesterase (2.56 mg galanthamin equivalents/g), and had moderate effects on α-amylase, elastase, collagenase and hyaluronidase. Balkan heath could be recommended for raw material production with antioxidant and enzyme inhibitory properties.

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Santa, Kazuki, Yoshio Kumazawa, and Isao Nagaoka. "The Potential Use of Grape Phytochemicals for Preventing the Development of Intestine-Related and Subsequent Inflammatory Diseases." Endocrine, Metabolic & Immune Disorders - Drug Targets 19, no. 6 (2019): 794–802. http://dx.doi.org/10.2174/1871530319666190529105226.

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Background: Grape phytochemicals prevent intestine-related and subsequent other inflammatory diseases. Phytochemicals and vitamin D are useful for the regulation of inflammatory responses. Phytochemicals is the generic name for terpenoids, carotenoids, and flavonoids that consist of a variety of chemicals contained in vegetables and fruits. There are a variety of grape cultivars that contain many kinds of phytochemicals in their skin and seeds. Grape phytochemicals including Grape Seed Extracts (GSE) have already been used to maintain healthy condition through manipulating inflammatory responses by decreasing the expression of inflammation-related factors. Discussion: Grape phytochemicals mainly consist of a variety of chemicals that include terpenoid (oleanolic acid), carotenoids (β-carotene, lutein), and flavonoids: flavon-3-ols (quercetin), flavan-3-ols (catechins), anthocyanins, oligomers and polymers (tannins and proanthocyanidins), and resveratrol. Phytochemicals improve the dysbiosis (gut microbiota complication) induced by metabolic syndrome and regulate inflammatory diseases induced by TNF-α production. Once absorbed, flavonoids change into glucuronide-form, move into the bloodstream and reach the inflammatory sites including liver, lung, and sites of arteriosclerosis, where they become active. Furthermore, oleanolic acid acts on TGR5 - the cholic acid receptor, as an agonist of cholic acid. These anti-inflammatory effects of phytochemicals have been proven by the experimental animal studies and the clinical trials. Conclusion: It is expected the new health food products will be created from grape skins and seeds since grape phytochemicals participate in the prevention of inflammatory diseases like intestine-related inflammatory diseases.

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Hao, Qian, Yoshinori Saito, Yosuke Matsuo, Hai-Zhou Li, and Takashi Tanaka. "Chalcane–stilbene conjugates and oligomeric flavonoids from Chinese Dragon’s Blood produced from Dracaena cochinchinensis." Phytochemistry 119 (November 2015): 76–82. http://dx.doi.org/10.1016/j.phytochem.2015.09.009.

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Dong, Jing, Yong Zhang, Yutao Chen, et al. "Baicalin Inhibits the Lethality of Shiga-Like Toxin 2 in Mice." Antimicrobial Agents and Chemotherapy 59, no. 11 (2015): 7054–60. http://dx.doi.org/10.1128/aac.01416-15.

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ABSTRACTShiga-like toxins (Stxs), produced by pathogenicEscherichia coli, are a major virulence factor involved in severe diseases in human and animals. These toxins are ribosome-inactivating proteins, and treatment for diseases caused by them is not available. Therefore, there is an urgent need for agents capable of effectively targeting this lethal toxin. In this study, we identified baicalin, a flavonoid compound used in Chinese traditional medicine, as a compound against Shiga-like toxin 2 (Stx2). We found that baicalin significantly improves renal function and reduces Stx2-induced lethality in mice. Further experiments revealed that baicalin induces the formation of oligomers by the toxin by direct binding. We also identified the residues important for such interactions and analyzed their roles in binding baicalin by biophysical and biochemical analyses. Our results establish baicalin as a candidate compound for the development of therapeutics against diseases caused by Stxs.

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Ageeva, Natalya Mikhailovna, Vladimir Aramovich Markosov, Irina Anatol'yevna Ilyina, and Aleksandr Vyacheslavovich Dergunov. "PHENOLIC COMPOUNDS OF RED GRAPE VARIETIES GROWING IN THE KRASNODAR TERRITORY." chemistry of plant raw material, no. 2 (June 10, 2021): 201–8. http://dx.doi.org/10.14258/jcprm.2021027427.

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Experimental data on the concentration of phenolic compounds in classical Vitis vinifera grapes and hybrid varieties growing in various soil and climatic zones of the Krasnodar Territory are presented. It has been shown that the technological stock of phenolic compounds varies widely – from 5420 to 7360 mg / dm3, depending on the grape variety and the place of its growth. Moreover, in hybrid varieties, the accumulation of the sum of polyphenols is higher than in classical ones. according to the technological stock of PS, the studied varieties can be arranged in the following row: Golubok> Krasnostop anapsky> Harmony> Alkor, Saperavi. On the example of the Cabernet-Sauvignon variety, the influence of the place of grape growth on the technological stock of polyphenols is shown: the largest amount of the phenolic compounds was in the grapes of AF Myskhako, where the highest amount of active temperatures was noted. The farms of Temryuk district obtained close results. The largest amount of resveratrol stilbene, phenolic acids, including chlorogenic, gallic acid, was found in the must of Cabernet-Sauvignon grape variety grown in AF Myskhako and AZOS ViV. The identity of the qualitative composition of the phenolic complex of all investigated grape varieties, including hybrids, has been established. In the studied grape varieties, monomers of flavonoids are represented by anthocyanins, quercetin, (+) - D-catechin, (-) - epicatechin. Among the monomeric non-flavonoids, hydroxy acids were determined, among the oligomeric polyphenols, the oligomeric procyanidins B1, B2, B3, which are condensed derivatives of catechin, were found.

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Nawi, Liliwirianis, Wan Zuraida Wan Mohd Zain, Norizan Ahmat, et al. "Chemotaxonomic Relationship of Oligomer Resveratrol in Three Malaysian Dipterocarpus Species from the Taxonomic Tribe of Dipterocarpaceae." Indonesian Journal of Chemistry 24, no. 3 (2024): 672. http://dx.doi.org/10.22146/ijc.82848.

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A phytochemical investigation of three species of Malaysian Dipterocarpus contributed to the isolation of 22 compounds which consist of 15 oligostilbenoids, 2 terpenes, 2 coumarins, and 3 flavonoids. The isolation of flavonoids in the Dipterocarpaceae family is very limited. Moreover, 4-methoxepigallocatechin-3-O-O-(3-methyl) gallate (20) was isolated for the first time in the plant. The occurrence of 4-O-methylgallocatechin (18) and its stereoisomer; 4-O’-methylepigallocatechin (19) was first reported in the Dipterocarpaceae family. This study also reported the existence of several types of oligostilbenoids such as davidiol A (8), stenophyllol B (9), isohopeaphenol (11), resveratrol (1), and ampelopsin E (10) which are the first occurrence in Dipterocarpus genus and suggested a significant chemotaxonomic relationship between Dipterocarpus, more closely to Vatica which is classified under Dipterocarpeae tribe.

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Pfahl, Leonard, Sofia Catarino, Natacha Fontes, António Graça, and Jorge Ricardo-da-Silva. "Effect of Barrel-to-Barrel Variation on Color and Phenolic Composition of a Red Wine." Foods 10, no. 7 (2021): 1669. http://dx.doi.org/10.3390/foods10071669.

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Tangible variation of sensory characteristics is often observed in wine aged in similar barrels. Barrel-to-barrel variation in barrel-aged wines was investigated in respect of the most important phenolic compounds of oenological interest. A red wine was aged in 49 medium-toasted oak (Quercus petraea) barrels, from four cooperages, for 12 months. The resulting wines were evaluated for chromatic characteristics, anthocyanin-related parameters, total phenols, flavonoids and non-flavonoids phenols, flavanol monomers, and oligomeric and polymeric proanthocyanidins. PCA and ANOVA were applied to investigate the relationships between barrels and to assess cooperage and individual barrel effect. Three cooperages influenced the wine similarly during aging. Anthocyanin-related parameters showed the highest variation, 25–37%, other phenolics varied 3–8.5%, and with two exceptions, chromatic characteristics changed 1.7–3%. The relationship between the number of barrels and the expected variation for each analytical parameter was calculated, as reference for future measurements involving barrel lots, either in wine production or experimental design.

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Pinent, M., M. Blay, M. C. Bladé, M. J. Salvadó, L. Arola, and A. Ardévol. "Grape Seed-Derived Procyanidins Have an Antihyperglycemic Effect in Streptozotocin-Induced Diabetic Rats and Insulinomimetic Activity in Insulin-Sensitive Cell Lines." Endocrinology 145, no. 11 (2004): 4985–90. http://dx.doi.org/10.1210/en.2004-0764.

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Abstract Flavonoids are functional constituents of many fruits and vegetables. Some flavonoids have antidiabetic properties because they improve altered glucose and oxidative metabolisms of diabetic states. Procyanidins are flavonoids with an oligomeric structure, and it has been shown that they can improve the pathological oxidative state of a diabetic situation. To evaluate their effects on glucose metabolism, we administered an extract of grape seed procyanidins (PE) orally to streptozotocin-induced diabetic rats. This had an antihyperglycemic effect, which was significantly increased if PE administration was accompanied by a low insulin dose. The antihyperglycemic effect of PE may be partially due to the insulinomimetic activity of procyanidins on insulin-sensitive cell lines. PE stimulated glucose uptake in L6E9 myotubes and 3T3-L1 adipocytes in a dose-dependent manner. Like insulin action, the effect of PE on glucose uptake was sensitive to wortmannin, an inhibitor of phosphoinositol 3-kinase and to SB203580, an inhibitor of p38 MAPK. PE action also stimulated glucose transporter-4 translocation to the plasma membrane. In summary, procyanidins have insulin-like effects in insulin-sensitive cells that could help to explain their antihyperglycemic effect in vivo. These effects must be added to their antioxidant activity to explain why they can improve diabetic situations.

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Usenov, A. B., K. M. Samatova, Sh A. Sultanova, and J. E. Safarov. "Study of the composition of useful plant extracts." IOP Conference Series: Earth and Environmental Science 1231, no. 1 (2023): 012038. http://dx.doi.org/10.1088/1755-1315/1231/1/012038.

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Abstract The article presents research materials on the composition and properties of BAS in water-alcohol extracts of plants. Phenol-accumulating and spicy-aromatic wild plants were used as plant raw materials for obtaining extracts. In this work extracts of wild herbs and fruits among the variety of BAS contained in hydroalcoholic, substances with P-vitamin activity - a complex of monomeric and oligomeric forms of phenolic compounds are of particular scientific and practical importance. Extractions were found to be phenolic acids, flavonoids and tannins. The importance of these substances is that the activity of vitamin P is often related to the antioxidant potential of phytocactus.

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Feng, Jiao, Xiao-Lu Zhang, Ying-Ya Li, Ying-Yu Cui, and Yi-Han Chen. "Pinus massoniana Bark Extract: Structure–Activity Relationship and Biomedical Potentials." American Journal of Chinese Medicine 44, no. 08 (2016): 1559–77. http://dx.doi.org/10.1142/s0192415x16500877.

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Proanthocyanidins (PAs) belong to the condensed tannin subfamily of natural flavonoids. Recent studies have shown that the main bioactive compounds of Pinus massoniana bark extract (PMBE) are PAs, especially the proanthocyanidins B series, which play important roles in cell cycle arrest, apoptosis induction and migration inhibition of cancer cells in vivo and in vitro. PA-Bs are mixtures of oligomers and polymers composed of flavan-3-ol, and the relationship between their structure and corresponding biomedical potentials is summarized in this paper. The hydroxyl at certain positions or the linkage between different carbon atoms of different rings determines or affects their anti-oxidant and free radical scavenging bioactivities. The degree of polymerization and the water solubility of the reaction system also influence their biomedical potential. Taken together, PMBE has a promising future in clinical drug development as a candidate anticancer drug and as a food additive to prevent tumorigenesis. We hope this review will encourage interested researchers to conduct further preclinical and clinical studies to evaluate the anticancer activities of PMBE, its active constituents and their derivatives.

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Kovács, Dóra, Zita Karancsi, Orsolya Farkas, and Ákos Jerzsele. "Antioxidant Activity of Flavonoids in LPS-Treated IPEC-J2 Porcine Intestinal Epithelial Cells and Their Antibacterial Effect against Bacteria of Swine Origin." Antioxidants 9, no. 12 (2020): 1267. http://dx.doi.org/10.3390/antiox9121267.

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Beneficial effects of flavonoids are widely known in human medicine, but less information is available about their veterinary usage. Based on their antioxidant and antibacterial activity, proanthocyanidins (PAs) and luteolin (LUT) might be used in the prevention and treatment of gastrointestinal infections in swine. In this study, in vitro beneficial effects of grape seed oligomeric proanthocyanidins (GSOPs) and LUT were investigated against bacterial endotoxin (LPS)-induced oxidative stress in IPEC-J2 porcine epithelial intestinal cells. Furthermore, antibacterial effects of GSOP and LUT were assessed against field isolates of Escherichia coli and Salmonella enterica ser. Typhimurium. Both GSOP and LUT were found to possess potent in vitro antioxidant activity in LPS-treated IPEC-J2 cells; furthermore, they showed a bacteriostatic effect against the tested bacterial strains of porcine origin. Both flavonoids seem to be effective in the protection of porcine intestinal epithelial cells against Gram-negative bacteria in vitro, but further in vivo studies are necessary to confirm these activities and to establish their optimal dosage regimen for future usage in veterinary practice.

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Khlupova, Maria, Irina Vasil’eva, Galina Shumakovich, et al. "Enzymatic Polymerization of Dihydroquercetin (Taxifolin) in Betaine-Based Deep Eutectic Solvent and Product Characterization." Catalysts 11, no. 5 (2021): 639. http://dx.doi.org/10.3390/catal11050639.

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Deep eutectic solvents (DESs) are an alternative to conventional organic solvents in various biocatalytic reactions. Meanwhile, there have been few studies reporting on synthetic reactions in DESs or DES-containing mixtures involving oxidoreductases. In this work, we have studied the effects of several DESs based on betaine as the acceptor of hydrogen bonds on the catalytic activity and stability of laccase from the basidial fungus Trametes hirsuta and performed enzymatic polymerization of the flavonoid dihydroquercetin (DHQ, taxifolin) in a DES–buffer mixture containing 60 vol.% of betaine-glycerol DES (molar ratio 1:2). The use of the laccase redox mediator TEMPO enabled an increased yield of DHQ oligomers (oligoDHQ), with a number average molecular weight of 1800 g mol−1 and a polydispersity index of 1.09. The structure of the synthesized product was studied using different physicochemical methods. NMR spectroscopy showed that oligoDHQ had a linear structure with an average chain length of 6 monomers. A scheme for enzymatic polymerization of DHQ in a DES–buffer mixture was also proposed.

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Azadeh, Elham, Ummi Hani Abdullah, Nurul Basirah Md Ali, et al. "Development of Water Repellent, Non-Friable Tannin-Furanic-Fatty Acids Biofoams." Polymers 14, no. 22 (2022): 5025. http://dx.doi.org/10.3390/polym14225025.

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Tannin-furanic foams were prepared with a good yield using the addition of relatively small proportions of a polyflavonoid tannin extract esterified with either palmitic acid, oleic acid, or lauric acid by its reaction with palmitoyl chloride, oleyl chloride, or lauryl chloride. FTIR analysis allowed us to ascertain the esterification of the tannin, and MALDI-TOF analysis allowed us to identify a number of multi-esterified flavonoid oligomers as well as some linked to residual carbohydrates related to the equally esterified tannin. These foams presented a markedly decreased surface friability or no friability at all, and at densities lower than the standard foam they were compared to. Equally, these experimental foams presented a much-improved water repellence, as indicated by their initial wetting angle, its small variation over time, and its stabilization at a high wetting angle value, while the wetting angle of the standard foam control went to zero very rapidly. This conclusion was supported by the calculation of the total surface energy of their surfaces as well as of their dispersive and polar components.

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Campana, Priscilla R. V., Christina M. Coleman, Lirlândia P. Sousa, Mauro M. Teixeira, Daneel Ferreira, and Fernão C. Braga. "Mansoins C–F, Oligomeric Flavonoid Glucosides Isolated from Mansoa hirsuta Fruits with Potential Anti-inflammatory Activity." Journal of Natural Products 79, no. 9 (2016): 2279–86. http://dx.doi.org/10.1021/acs.jnatprod.6b00390.

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Dávid, Csilla Zsuzsanna, Norbert Kúsz, Orinamhe Godwin Agbadua, et al. "Phytochemical Investigation of Carex praecox Schreb. and ACE-Inhibitory Activity of Oligomer Stilbenes of the Plant." Molecules 29, no. 14 (2024): 3427. http://dx.doi.org/10.3390/molecules29143427.

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Phenolic compounds are the main special metabolites of Cyperaceae species from phytochemical, pharmacological, and chemotaxonomical points of view. The present study focused on the isolation, structure determination, and pharmacological investigation of constituents from Carex praecox. Twenty-six compounds, including lignans, stilbenes, flavonoids, megastigmanes, chromenes, and phenylpropanoids, were identified from the methanol extract of the plant. Five of these compounds, namely, carexines A–E, are previously undescribed natural products. All compounds were isolated for the first time from C. praecox. The ACE-inhibitory activity of seven stilbenoid compounds was tested, and (–)-hopeaphenol proved to be the most active (IC50 7.7 ± 0.9 μM). The enzyme–kinetic studies revealed a mixed-type inhibition; therefore, domain-specific studies were also conducted. The in silico docking of (–)-hopeaphenol to the ACE affirmed some favorable interactions. In addition, the antiproliferative and antibacterial effects of some compounds were also evaluated.

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Xu, Qi, Ziyu Chen, Borong Zhu, et al. "A-Type Cinnamon Procyanidin Oligomers Protect Against 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine-Induced Neurotoxicity in Mice Through Inhibiting the P38 Mitogen-Activated Protein Kinase/P53/BCL-2 Associated X Protein Signaling Pathway." Journal of Nutrition 150, no. 7 (2020): 1731–37. http://dx.doi.org/10.1093/jn/nxaa128.

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ABSTRACT Background Parkinson's disease (PD) is a common neurodegenerative disorder. Cinnamon procyanidin oligomers (CPOs) are flavonoids with many claimed health benefits. Objective This study aimed to elucidate the neuroprotection of A-type CPOs (CPO-A) and the underlying mechanisms in cultured cell and animal models of PD. Methods Thirty male mice (C57BL/6, 9-wk old) were assigned to 3 groups (n = 10), and were given daily gavage of saline [control and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) groups] or CPO-A (150 mg/kg, CPO-A group) during days 1–15 and daily intraperitoneal injections of saline (control group) or MPTP (20 mg/kg; MPTP and MPTP + CPO-A groups) during days 11–15. After the motor behavior test, all mice were killed on day 16 to collect the substantia nigra (SN) for assaying the neuroprotective effects of CPO-A. SH-SY5Y cells were treated with 12.5 μM CPO-A for 2 h or 3 activators of stress-related kinases (5–25 μM) for 12–48 h followed by 1 mM 1-methyl-4-phenylpyridinium (MPP+) for assays of viability, morphology, and stress status. Results Compared with the control, the MPTP treatment decreased (P &lt; 0.05) locomotor activity by 21%, and tyrosine hydroxylase (TH) positive neurons by 55% and Th mRNA concentration by 51% in the SN. The CPO-A treatment attenuated or restored (P &lt; 0.05) these changes and inhibited (P &lt; 0.05) the MPTP-induced activation of P38 mitogen-activated protein kinase (P38MAPK) and P53, along with the downstream expression of BCL-2 associated X protein (BAX) in the SN. In SH-SY5Y cells, the CPO-A treatment blocked (P &lt; 0.01) the MPP+-induced accumulation of intracellular reactive oxygen species and neurotoxicity. However, this protection was abolished (P &lt; 0.05) by activators of the P38MAPK/P53/BAX pathway. Conclusion CPO-A protected against MPP+-induced cytotoxicity in SH-SY5Y cells and MPTP-induced neurotoxicity in mice by regulating the P38MAPK/P53/BAX signaling. Our findings reveal a novel role and mechanism of a food flavonoid CPO-A in preventing neurodegeneration.

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Ngoc, Phu Cao, Laurent Leclercq, Jean-Christophe Rossi, et al. "Optimizing Water-Based Extraction of Bioactive Principles of Hawthorn: From Experimental Laboratory Research to Homemade Preparations." Molecules 24, no. 23 (2019): 4420. http://dx.doi.org/10.3390/molecules24234420.

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Hawthorn (Crataegus) is used for its cardiotonic, hypotensive, vasodilative, sedative, antiatherosclerotic, and antihyperlipidemic properties. One of the main goals of this work was to find a well-defined optimized extraction protocol usable by each of us that would lead to repeatable, controlled, and quantified daily uptake of active components from hawthorn at a drinkable temperature (below 60 °C). A thorough investigation of the extraction mode in water (infusion, maceration, percolation, ultrasounds, microwaves) on the yield of extraction and the amount of phenolic compounds, flavonoids, and proanthocyanidin oligomers as well as on the Ultra High Performance Liquid Chromatography (UHPLC) profiles of the extracted compounds was carried out. High-resolution Fourier transform ion cyclotron resonance mass spectrometry was also implemented to discriminate the different samples and conditions of extraction. The quantitative and qualitative aspects of the extraction as well as the kinetics of extraction were studied, not only according to the part (flowers or leaves), the state (fresh or dried), and the granulometry of the dry plant, but also the stirring speed, the temperature, the extraction time, the volume of the container (cup, mug or bowl) and the use of infusion bags.

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Kováč, Ján, Lívia Slobodníková, Eva Trajčíková, et al. "Therapeutic Potential of Flavonoids and Tannins in Management of Oral Infectious Diseases—A Review." Molecules 28, no. 1 (2022): 158. http://dx.doi.org/10.3390/molecules28010158.

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Medicinal plants are rich sources of valuable molecules with various profitable biological effects, including antimicrobial activity. The advantages of herbal products are their effectiveness, relative safety based on research or extended traditional use, and accessibility without prescription. Extensive and irrational usage of antibiotics since their discovery in 1928 has led to the increasing expiration of their effectiveness due to antibacterial resistance. Now, medical research is facing a big and challenging mission to find effective and safe antimicrobial therapies to replace inactive drugs. Over the years, one of the research fields that remained the most available is the area of natural products: medicinal plants and their metabolites, which could serve as active substances to fight against microbes or be considered as models in drug design. This review presents selected flavonoids (such as apigenin, quercetin, kaempferol, kurarinone, and morin) and tannins (including oligomeric proanthocyanidins, gallotannins, ellagitannins, catechins, and epigallocatechin gallate), but also medicinal plants rich in these compounds as potential therapeutic agents in oral infectious diseases based on traditional usages such as Agrimonia eupatoria L., Hamamelis virginiana L., Matricaria chamomilla L., Vaccinium myrtillus L., Quercus robur L., Rosa gallica L., Rubus idaeus L., or Potentilla erecta (L.). Some of the presented compounds and extracts are already successfully used to maintain oral health, as the main or additive ingredient of toothpastes or mouthwashes. Others are promising for further research or future applications.

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Journal articles on the topic 'Flavonoidal oligomers'

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