Articles de revues : « Flavonoidi naturali »

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Choi, Roy C. Y., Judy T. T. Zhu, Amanda W. Y. Yung, Pinky S. C. Lee, Sherry L. Xu, Ava J. Y. Guo, Kevin Y. Zhu, Tina T. X. Dong et Karl W. K. Tsim. « Synergistic Action of Flavonoids, Baicalein, and Daidzein in Estrogenic and Neuroprotective Effects : A Development of Potential Health Products and Therapeutic Drugs against Alzheimer’s Disease ». Evidence-Based Complementary and Alternative Medicine 2013 (2013) : 1–10. http://dx.doi.org/10.1155/2013/635694.

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Despite the classical hormonal effect, estrogen has been reported to mediate neuroprotection in the brain, which leads to the searching of estrogen-like substances for treating neurodegenerative diseases. Flavonoids, a group of natural compounds, are well known to possess estrogenic effects and used to substitute estrogen, that is, phytoestrogen. Flavonoid serves as one of the potential targets for the development of natural supplements and therapeutic drugs against different diseases. The neuroprotection activity of flavonoids was chosen for a possible development of anti-Alzheimer's drugs or food supplements. The estrogenic activity of two flavonoids, baicalein and daidzein, were demonstrated by their strong abilities in stimulating estrogen receptor phosphorylation and transcriptional activation of estrogen responsive element in MCF-7 breast cells. The neuroprotection effects of flavonoids againstβ-amyloid (Aβ) were revealed by their inhibition effects onin vitroAβaggregation and Aβ-induced cytotoxicity in PC12 neuronal cells. More importantly, the estrogenic and neuroprotective activities of individual flavonoid could be further enhanced by the cotreatment in the cultures. Taken together, this synergistic effect of baicalein and daidzein might serve as a method to improve the therapeutic efficacy of different flavonoids against Aβ, which might be crucial in developing those flavonoidsin treating Alzheimer's disease in the future.

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Arshad, Nasima, Naveed K. Janjua, Athar Y. Khan, Azra Yaqub, Torsten Burkholz et Claus Jacob. « Natural Flavonoids Interact with Dinitrobenzene System in Aprotic Media : An Electrochemical Probing ». Natural Product Communications 7, n^o 3 (mars 2012) : 1934578X1200700. http://dx.doi.org/10.1177/1934578x1200700309.

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Three structurally related natural flavonoids (FlOH), quercetin (Q), rutin (R) and morin (M), were investigated by cyclic voltammetry to probe their interactions with hazardous 1,4-dinitrobenzene (1,4-DNB) using a glassy carbon electrode. Scavenging of 1,4-DNB by FlOH was inferred from a positive shift in reduction potential, decrease in anodic peak current, and irreversible electrochemical behavior of 1,4-DNB on increasing the flavonoid concentration. The homogeneous bi-molecular rate constant (k2) was determined using the Nicholson-Shain equation and found to be higher for the dianion. Morin posed a comparatively higher k2 value for its interaction with the 1,4-DNB electrochemical system owing to its more acidic nature and least intramolecular hydrogen bonding. The cyclic voltammetric (CV) results were further supported by HyperchemPM3 quantum mechanical semi-empirical calculations, which point towards ErCi interactions between flavonoids and 1,4-DNB. The present investigation is biologically significant in terms of natural flavonoidal scavenging activity toward toxins such as dinitroaromatics.

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Hurtová, Martina, David Biedermann, Zuzana Osifová, Josef Cvačka, Kateřina Valentová et Vladimír Křen. « Preparation of Synthetic and Natural Derivatives of Flavonoids Using Suzuki–Miyaura Cross-Coupling Reaction ». Molecules 27, n^o 3 (31 janvier 2022) : 967. http://dx.doi.org/10.3390/molecules27030967.

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Herein, we report the use of the Suzuki–Miyaura cross-coupling reaction for the preparation of a library of synthetic derivatives of flavonoids for biological activity assays. We have investigated the reactivity of halogenated flavonoids with aryl boronates and with boronyl flavonoids. This reaction was used to prepare new synthetic derivatives of flavonoids substituted at C-8 with aryl, heteroaryl, alkyl, and boronate substituents. The formation of flavonoid boronate enabled a cross-coupling reaction with halogenated flavones yielding biflavonoids connected at C-8. This method was used for the preparation of natural compounds including C-8 prenylated compounds, such as sinoflavonoid NB. Flavonoid boronates were used for the preparation of rare C-8 hydroxyflavonoids (natural flavonoids gossypetin and hypolaetin). A series of previously unknown derivatives of quercetin and luteolin were prepared and fully characterized.

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Parwata, Adi, Putra Manuaba et Sutirta Yasa. « The Potency of Flavonoid Compounds in water Extract Gyrinops Versteegii Leaves as Natural Antioxidants Sources ». Biomedical and Pharmacology Journal 11, n^o 3 (17 septembre 2018) : 1501–11. http://dx.doi.org/10.13005/bpj/1517.

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Flavonoids can provide antioxidant effects by preventing the formation of ROS, directly capture ROS, protect lipophilic antioxidants and stimulate the increase of enzymatic antioxidants. Flavonoids are phenolic compounds that are widely found in medicinal plants, one of which is Gyrinops versteegii leaves. In this research to determine the potential of flavonoids in water extract Gyrinop versteegii as one source of natural antioxidants was investigated. This research begins with maceration of Gyrinops versteegii leaves with some solvents such as ethyl acetate, ethanol, methanol and water. Each of the extracts obtained measured the total content of Phenol. The extract, which had the highest total phenol content, measured the total flavonoid content and antioxidant capacity. The active extract as antioxidant was further isolated and identified its flavonoid content. Flavonoids obtained measured antioxidant capacity in vitro. Total phenol (mg GAE/100 g) of ethyl acetate extract = 443, ethanol extract =1.510, methanol extract = 6.069 and water extract = 14.979, total flavonoid contens = 2298, 977 mg QE/100 gram, containing phenol, flavonoid, tannin, alkaloid and steroid compounds. Antioxidant capacity with IC50 = 3,45 ppm (5 min.) and 3,05 (60 min.). Identification of isolates with UV-Vis spectroscopy showed 2 absorption bands namely band I at 352 nm and band II at 256 nm. Addition of AlCl3 / HCl shear reagent showed band I undergoing a 2 nm batochromic shift. These results indicate that the resulting flavonoid is suspected to be a flavonoid group of flavonol substituted -OH group at C-5 or 5-hydroxy-flavonol. and its antioxidant capacity or IC50 = 17,14 ppm. These results indicate that the isolated flavonoid has very strong antioxidant activity and is potentially developed as a natural antioxidant.

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Brou, Kouassi Guy, Jean Luc Aboya Moroh, Sékou Diabaté, Boni N’zue, Goli Pierre Zouhouri, Janat Ackanovna Mamyrbekova-Bekro, II Nazaire Koffi Kouassi, Denézon Odette Dogbo et Yves-Alain Bekro. « Physiological mechanism of resistance antibiosis to anthracnose of different Manihot varieties ». International Journal of Biological and Chemical Sciences 14, n^o 8 (9 décembre 2020) : 2854–69. http://dx.doi.org/10.4314/ijbcs.v14i8.16.

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Cassava is one of the main food crops in Africa, particularly in Côte d'Ivoire. However, the cultivated varieties are prone to attack by diseases. The present work focused on the role of phenolic and in particular flavonoid resistance markers in the Manihot esculenta-Colletotrichum gloeosporioides pathosystem. The aim was to elucidate the involvement of flavonoid antibiosis in the natural defense of three cultivars of M. esculenta when confronted with attacks by C. gloeosporioides. The quantitative dosage approach for total phenolics and flavonoids as well as the identification of flavonoid antibiosis have been carried out. The results revealed that the cultivars 9620A, TMS30572 and YACE of M. esculenta have, after the C. gloeosporioides inoculation tests, reacted early 2 days after inoculation (JAI) and accumulated relatively high levels of antibiosis phenolic and flavonoid 9JAI. The three cultivars accumulated constitutive flavonoid antibiosis and 3 neosynthesized antibiosis from 7JAI to 9JAI. The accumulation of flavonoid antibacterials neosynthesized in the stems and in the leaves testify to the expression of a systemic resistance of the cassava plants. The cultivars 9620A and TMS30572 are more tolerant than cultivar YACE. This study approach has made it possible to discriminate between cultivars and can therefore be used as a complementary selection tool to traditional selection tests.Keywords: Manihot esculenta, anthracnose, flavonoïd antibisis, glyphosate.

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Slámová, Kristýna, Jana Kapešová et Kateřina Valentová. « “Sweet Flavonoids” : Glycosidase-Catalyzed Modifications ». International Journal of Molecular Sciences 19, n^o 7 (21 juillet 2018) : 2126. http://dx.doi.org/10.3390/ijms19072126.

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Natural flavonoids, especially in their glycosylated forms, are the most abundant phenolic compounds found in plants, fruit, and vegetables. They exhibit a large variety of beneficial physiological effects, which makes them generally interesting in a broad spectrum of scientific areas. In this review, we focus on recent advances in the modifications of the glycosidic parts of various flavonoids employing glycosidases, covering both selective trimming of the sugar moieties and glycosylation of flavonoid aglycones by natural and mutant glycosidases. Glycosylation of flavonoids strongly enhances their water solubility and thus increases their bioavailability. Antioxidant and most biological activities are usually less pronounced in glycosides, but some specific bioactivities are enhanced. The presence of l-rhamnose (6-deoxy-α-l-mannopyranose) in rhamnosides, rutinosides (rutin, hesperidin) and neohesperidosides (naringin) plays an important role in properties of flavonoid glycosides, which can be considered as “pro-drugs”. The natural hydrolytic activity of glycosidases is widely employed in biotechnological deglycosylation processes producing respective aglycones or partially deglycosylated flavonoids. Moreover, deglycosylation is quite commonly used in the food industry aiming at the improvement of sensoric properties of beverages such as debittering of citrus juices or enhancement of wine aromas. Therefore, natural and mutant glycosidases are excellent tools for modifications of flavonoid glycosides.

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Fan, Xiaolan, Ziqiang Fan, Ziyue Yang, Tiantian Huang, Yingdong Tong, Deying Yang, Xueping Mao et Mingyao Yang. « Flavonoids—Natural Gifts to Promote Health and Longevity ». International Journal of Molecular Sciences 23, n^o 4 (16 février 2022) : 2176. http://dx.doi.org/10.3390/ijms23042176.

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The aging of mammals is accompanied by the progressive atrophy of tissues and organs and the accumulation of random damage to macromolecular DNA, protein, and lipids. Flavonoids have excellent antioxidant, anti-inflammatory, and neuroprotective effects. Recent studies have shown that flavonoids can delay aging and prolong a healthy lifespan by eliminating senescent cells, inhibiting senescence-related secretion phenotypes (SASPs), and maintaining metabolic homeostasis. However, only a few systematic studies have described flavonoids in clinical treatment for anti-aging, which needs to be explored further. This review first highlights the association between aging and macromolecular damage. Then, we discuss advances in the role of flavonoid molecules in prolonging the health span and lifespan of organisms. This study may provide crucial information for drug design and developmental and clinical applications based on flavonoids.

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GEMMELL, CHRISTOPHER T., VALERIA R. PARREIRA et JEFFREY M. FARBER. « Controlling Listeria monocytogenes Growth and Biofilm Formation Using Flavonoids ». Journal of Food Protection 85, n^o 4 (4 janvier 2022) : 639–46. http://dx.doi.org/10.4315/jfp-21-135.

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ABSTRACT The aim of this study was to investigate the ability of natural plant-derivate products (flavonoid compounds) to inhibit the growth and biofilm-forming ability of Listeria monocytogenes. A collection of 500 synthetic and natural flavonoids were tested individually on strains of L. monocytogenes for their antimicrobial and antibiofilm activity. The flavonoids were tested against a L. monocytogenes cocktail of five strains at a concentration of 100 μM to determine their effect on planktonic growth. The optical density was measured every hour for 24 h at 37°C, and every hour for 48 h at 22°C. A total of 17 flavonoids were chosen for further study because of their ability to significantly reduce the growth of L. monocytogenes up to 97%. An additional two flavonoids that increased planktonic growth were chosen as well to investigate whether they had the same effect on biofilm growth. A lower concentration of flavonoid compounds (50 μM) was selected to investigate the individual effects on L. monocytogenes biofilm formation using (i) stainless steel coupons to quantify biomass using crystal violet staining and (ii) glass slides using confocal laser scanning microscopic (CLSM) imaging to observe the biofilm architecture. The 19 flavonoids showed various levels of L. monocytogenes biofilm growth inhibition, ranging from 2 to 100% after 48 h of incubation at 22 or 10°C. This includes 18 of the 19 flavonoids significantly (P ≤ 0.05) inhibiting L. monocytogenes biofilm formation on stainless steel coupons under at least one of the testing conditions. However, only one flavonoid compound demonstrated significant biofilm inhibition (P ≤ 0.05) under all conditions tested. Furthermore, 8 of the selected 19 flavonoid compounds showed visible reductions through CLSM in L. monocytogenes biofilm formation. Overall, we identified five flavonoid compounds to be promising antibiofilm and antimicrobial agents against L. monocytogenes. HIGHLIGHTS

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Yan, Shiqiang, Mingxian Xie, Yujie Wang, Qiang Xiao, Ning Ding et Yingxia Li. « Semi-synthesis of a series natural flavonoids and flavonoid glycosides from scutellarin ». Tetrahedron 76, n^o 8 (février 2020) : 130950. http://dx.doi.org/10.1016/j.tet.2020.130950.

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Wisnumurti, Rafi Firdaus, Solmaz Aslanzadeh et Arli Aditya Parikesit. « COMPUTATIONAL EXAMINATION OF FLAVONOID COMPOUNDS : UTILIZATION OF MOLECULAR SIMULATION TO DISCOVER DRUG CANDIDATES FOR COVID-19 ». RASAYAN Journal of Chemistry 15, n^o 02 (2022) : 1132–36. http://dx.doi.org/10.31788/rjc.2022.1526877.

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Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the novel coronavirus disease 19 (COVID19) pandemic. Despite drugs had been deployed through intense research, none has been proven to cure the infection. Flavonoids, a natural substance, have been reported to exhibit various pharmaceutical and medical properties. The aim of this research is to discover lead compounds for covid-19 from flavonoid compounds through in silico study. Through computational examination, the potential of flavonoid compounds against SARS-CoV-2 has been examined and it shows that some flavonoids have potential against SARS-CoV-2.

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Li, Meng, Mengqi Qian, Qian Jiang, Bie Tan, Yulong Yin et Xinyan Han. « Evidence of Flavonoids on Disease Prevention ». Antioxidants 12, n^o 2 (20 février 2023) : 527. http://dx.doi.org/10.3390/antiox12020527.

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A growing body of evidence highlights the properties of flavonoids in natural foods for disease prevention. Due to their antioxidative, anti-inflammatory, and anti-carcinogenic activities, flavonoids have been revealed to benefit skeletal muscle, liver, pancreas, adipocytes, and neural cells. In this review, we introduced the basic classification, natural sources, and biochemical properties of flavonoids, then summarize the experimental results and underlying molecular mechanisms concerning the effects of flavonoid consumption on obesity, cancers, and neurogenerative diseases that greatly threaten public health. Especially, the dosage and duration of flavonoids intervening in these diseases are discussed, which might guide healthy dietary habits for people of different physical status.

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Sayre, Casey, et Neal Davies. « Quantification of Three Chiral Flavonoids with Reported Bioactivity in Selected Licensed Canadian Natural Health Products and US Marketed Dietary Supplements ». Journal of Pharmacy & ; Pharmaceutical Sciences 16, n^o 2 (14 juin 2013) : 272. http://dx.doi.org/10.18433/j3x01q.

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Purpose. Research indicating potentially beneficial bioactivity of flavonoids has produced a market and demand for natural health products and dietary supplements containing flavonoids. Implementation of the Canadian natural health product (NHP) regulations in January of 2004 increased regulation and oversight of NHP manufacture and marketing leading many consumers and clinicians to assume a similar pathway of development and approval to over-the-counter or prescription drugs. Methods. Three stereospecific liquid chromatograph/mass spectrometry (LC/MS) methods were used to assess the flavonoids, liquiritigenin, pinocembrin, and pinostrobin, in selected Canadian licensed NHP’s and US marketed dietary supplements. Results. The present study quantifies bioactive flavonoids in these products and notes variability in flavonoid content. Conclusions. Efficacy and safety of NHP’s and dietary supplements should not be assumed due to differences in criteria for NHP licensure by Health Canada as well as variation of flavonoid content between manufacturers and products with similar indications for use. This article is open to POST-PUBLICATION REVIEW. Registered readers (see “For Readers”) may comment by clicking on ABSTRACT on the issue’s contents page.

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Carmona-Hernandez, Juan Carlos, Mai Le, Ana María Idárraga-Mejía et Clara Helena González-Correa. « Flavonoid/Polyphenol Ratio in Mauritia flexuosa and Theobroma grandiflorum as an Indicator of Effective Antioxidant Action ». Molecules 26, n^o 21 (25 octobre 2021) : 6431. http://dx.doi.org/10.3390/molecules26216431.

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Studies on polyphenols and flavonoids in natural products reveal benefits in the prevention of multiple diseases. Proper extraction, treatment of extracts, and quantification of polyphenols and flavonoids demand attention from the scientific community in order to report more specific biological action. Total polyphenol content (TPC) and total flavonoid content (TFC) (measured at three different times) of ethanol, methanol and acetone extracts of Mauritia flexuosa (aguaje) and Theobroma grandiflorum (copoazú) fresh pulp, from the Colombian Amazon region, were evaluated with the purpose of focusing in the polyphenol/flavonoid proportion and its effective antioxidant activity. This objective could help to explain specific flavonoid biological action based on higher flavonoid proportion rather than higher total polyphenol content. Differences in extracting solvents resulted in statistically significant different yields; the highest TPC was observed with acetone 70% in Mauritia flexuosa and ethanol 80% for T. grandiflorum. The best flavonoid/polyphenol ratio in M. flexuosa was about 1:2.4 and 1:12.8 in T. grandiflorum and the antioxidant efficacy was proportionally higher for flavonoids extracted from T. grandiflorum. HPLC analysis revealed 54 µg/g of the flavonoid kaempferol in M. Flexuosa and 29 µg/g in T. grandiflorum. Further studies evaluating this proportionality, in seeds or peel of fruits, as well as, other specific biological activities, could help to understand the detailed flavonoid action without focusing on the high total polyphenol content.

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Zhang, Changyue, Yanzhi Liu, Xiaojing Liu, Xiaochuan Chen et Ruijiao Chen. « Comprehensive Review of Recent Advances in Chiral A-Ring Flavonoid Containing Compounds : Structure, Bioactivities, and Synthesis ». Molecules 28, n^o 1 (2 janvier 2023) : 365. http://dx.doi.org/10.3390/molecules28010365.

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Flavonoids are a group of natural polyphenolic substances that are abundant in vegetables, fruits, grains, and tea. Chiral A-ring-containing flavonoids are an important group of natural flavonoid derivatives applicable in a wide range of biological activities such as, cytotoxic, anti-inflammatory, anti-microbial, antioxidant, and enzyme inhibition. The desirable development of chiral A-ring-containing flavonoids by isolation, semi-synthesis or total synthesis in a short duration proves their great value in medicinal chemistry research. In this review, the research progress of chiral A-ring-containing flavonoids, including isolation and extraction, structural identification, pharmacological activities, and synthetic methods, is comprehensively and systematically summarized. Furthermore, we provide suggestions for future research on the synthesis and biomedical applications of flavonoids.

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Tanamal, Mersy T., Pamella Mercy Papilaya et Alwi Smith. « KANDUNGAN SENYAWA FLAVONOID PADA DAUN MELINJO (Gnetum gnemon L.) BERDASARKAN PERBEDAAN TEMPAT TUMBUH ». BIOPENDIX : Jurnal Biologi, Pendidikan dan Terapan 3, n^o 2 (20 mars 2017) : 142–47. http://dx.doi.org/10.30598/biopendixvol3issue2page142-147.

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Background: The village of Latuhalat and Kayu Putih village is a place that is on the beach and in the mountains. Potential natural resources are quite a lot of plants melinjo (Gnetum gnemon L). This study aims to determine the total compound of flavonoid content of leaf melinjo (Gnetum gnemon L) based on place difference. Method: The method used in this study using the method of Chang et al. The solvent used for diluting the melinjo extract was methanol solvent, then measured using a UV-VIS spectrophotometer. Result: Result of analysis of flavonoid compound content, Latuhalat Village has average total flavonoid content of13.080% and average total flavonoid content in Kayu Putih Village equal to 17.028%. Kayu Putih Village has more flavonoid compound than Latuhalat Village. Conclusion: Total levels of melinjo leaf flavonoids (Gnetum gnemon L) in Kayu Putih Village were more than total flavonoids of leaf melinjo (Gnetum gnemon L) in Latuhalat Village.

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Wang, Bixia, Jipeng Qu, Siyuan Luo, Shiling Feng, Tian Li, Ming Yuan, Yan Huang, Jinqiu Liao, Ruiwu Yang et Chunbang Ding. « Optimization of Ultrasound-Assisted Extraction of Flavonoids from Olive (Olea europaea) Leaves, and Evaluation of Their Antioxidant and Anticancer Activities ». Molecules 23, n^o 10 (30 septembre 2018) : 2513. http://dx.doi.org/10.3390/molecules23102513.

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Olea europaea leaves are the major byproduct of olive farming. In this study, ultrasound-assisted extraction of flavonoids from olive leaves was optimized using response surface methodology, and the flavonoid compounds and their antioxidant and anticancer activities were investigated by high performance liquid chromatography. The results showed that the optimized conditions for achieving the maximum yield of flavonoids (74.95 mg RE/g dm) were 50 °C temperature, 270 W power, 50 min time, and 41 mL/g liquid-solid ratio. There was a significant difference in the total flavonoid content between the aged and young leaves harvested in April and July, and six main components were quantified. Among them, luteolin-4’-O-glucoside was the most predominant flavonoid compound, followed by apigenin-7-O-glucoside and rutin. Olive leaves also contained small amounts of luteolin, apigenin, and quercetin. Additionally, excellent antioxidant activity was exhibited when tested with the DPPH assay; superoxide radical-scavenging ability and reducing power was also tested. The anticancer activity of the flavonoids was assessed using HeLa cervical cancer cells, and it was observed that increasing concentrations of olive leaf flavonoids resulted in decreased cancer cell viability. These results suggest that the flavonoids from olive leaves could be used as a potential source of natural antioxidants for the pharmaceutical and food industries.

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Park, Hye Lin, Jae Chul Lee, Kyungha Lee, Jeong Min Lee, Hyo Jeong Nam, Seong Hee Bhoo, Tae Hoon Lee, Sang-Won Lee et Man-Ho Cho. « Biochemical Characterization of a Flavonoid O-methyltransferase from Perilla Leaves and Its Application in 7-Methoxyflavonoid Production ». Molecules 25, n^o 19 (28 septembre 2020) : 4455. http://dx.doi.org/10.3390/molecules25194455.

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Methylation is a common structural modification that can alter and improve the biological activities of natural compounds. O-Methyltransferases (OMTs) catalyze the methylation of a wide array of secondary metabolites, including flavonoids, and are potentially useful tools for the biotechnological production of valuable natural products. An OMT gene (PfOMT3) was isolated from perilla leaves as a putative flavonoid OMT (FOMT). Phylogenetic analysis and sequence comparisons showed that PfOMT3 is a class II OMT. Recombinant PfOMT3 catalyzed the methylation of flavonoid substrates, whereas no methylated product was detected in PfOMT3 reactions with phenylpropanoid substrates. Structural analyses of the methylation products revealed that PfOMT3 regiospecifically transfers a methyl group to the 7-OH of flavonoids. These results indicate that PfOMT3 is an FOMT that catalyzes the 7-O-methylation of flavonoids. PfOMT3 methylated diverse flavonoids regardless of their backbone structure. Chrysin, naringenin and apigenin were found to be the preferred substrates of PfOMT3. Recombinant PfOMT3 showed moderate OMT activity toward eriodictyol, luteolin and kaempferol. To assess the biotechnological potential of PfOMT3, the biotransformation of flavonoids was performed using PfOMT3-transformed Escherichia coli. Naringenin and kaempferol were successfully bioconverted to the 7-methylated products sakuranetin and rhamnocitrin, respectively, by E. coli harboring PfOMT3.

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Sun, Ying, Mei Gao, Seogchan Kang, Chengmin Yang, Hui Meng, Yun Yang, Xiangsheng Zhao et al. « Molecular Mechanism Underlying Mechanical Wounding-Induced Flavonoid Accumulation in Dalbergia odorifera T. Chen, an Endangered Tree That Produces Chinese Rosewood ». Genes 11, n^o 5 (28 avril 2020) : 478. http://dx.doi.org/10.3390/genes11050478.

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Dalbergia odorifera, a critically endangered tree species, produces heartwood containing a vast variety of flavonoids. This heartwood, also known as Chinese rosewood, has high economic and medicinal value, but its formation takes several decades. In this study, we showed that discolored wood induced by pruning displays similar color, structure, and flavonoids content to those of natural heartwood, suggesting that wounding is an efficient method for inducing flavonoid production in D. odorifera. Transcriptome analysis was performed to investigate the mechanism underlying wounding-induced flavonoids production in D. odorifera heartwood. Wounding upregulated the expression of 90 unigenes, which covered 19 gene families of the phenylpropanoid and flavonoid pathways, including PAL, C4H, 4CL, CHS, CHI, 6DCS, F3’5’H, F3H, FMO, GT, PMAT, CHOMT, IFS, HI4’OMT, HID, IOMT, I2’H, IFR, and I3’H. Furthermore, 47 upregulated unigenes were mapped to the biosynthesis pathways for five signal molecules (ET, JA, ABA, ROS, and SA). Exogenous application of these signal molecules resulted in the accumulation of flavonoids in cell suspensions of D. odorifera, supporting their role in wounding-induced flavonoid production. Insights from this study will help develop new methods for rapidly inducing the formation of heartwood with enhanced medicinal value.

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Manck, Lauren, Ester Quintana, Rocío Suárez, Fernando G. Brun, Ignacio Hernández, María J. Ortega et Eva Zubía. « Profiling of Phenolic Natural Products in the Seagrass Zostera noltei by UPLC-MS ». Natural Product Communications 12, n^o 5 (mai 2017) : 1934578X1701200. http://dx.doi.org/10.1177/1934578x1701200511.

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Seagrasses are marine plants that play important ecological functions in coastal ecosystems. The species Zostera noltei is widely distributed along the European coasts thriving in a variety of environmental conditions. In this study, the phenolic natural products of Z. noltei have been analyzed quantitatively by using UPLC-MS. Plants from the Natural Park of the Bay of Cadiz (Spain) were shown to contain rosmarinic acid (1) and the flavonoids apigenin-7- O-glucoside (2), luteolin-7-sulfate (7), apigenin-7-sulfate (8), diosmetin-7-sulfate (9), and acacetin-7-sulfate (10). The analysis by UPLC-MS of extracts allowed the quantification of all the compounds and evidenced the intraspecific variations in the profile of natural products among plants collected at different dates and locations within the Bay. The flavonoids 2, and 7-10 were present in all the analyzed samples with a total flavonoid content in the range 12.8–72.3 mg/g dry wt, while rosmarinic acid (1) was only present in some samples, reaching up to 19.6 mg/g dry wt. A distinctive feature of plants from the Bay of Cadiz is the common presence of apigenin-7-sulfate (8) as major flavonoid, differing from plants from other regions whose major flavonoid is diosmetin-7-sulfate (9).

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Wang, Kui-Wu, et Ting-Ting Zhang. « Bioactive Flavonoids from Verbenaceae ». Mini-Reviews in Organic Chemistry 17, n^o 6 (24 août 2020) : 754–66. http://dx.doi.org/10.2174/1570193x16666191007170602.

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Flavonoids are widely distributed in the plant kingdom and possess a variety of biological activities, such as anti-oxidant, anti-inflammatory, and anti-viral activities. Due to the structural diversity and biological activity, flavonoid derivatives isolated from Verbenaceae family have received a lot of attention by the research scholars. In this paper, a total of 150 natural flavonoids isolated from Verbenaceae and their bioactivities were summarized.

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Dias, Maria Celeste, Diana C. G. A. Pinto et Artur M. S. Silva. « Plant Flavonoids : Chemical Characteristics and Biological Activity ». Molecules 26, n^o 17 (4 septembre 2021) : 5377. http://dx.doi.org/10.3390/molecules26175377.

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In recent years, more attention has been paid to natural sources of antioxidants. Flavonoids are natural substances synthesized in several parts of plants that exhibit a high antioxidant capacity. They are a large family, presenting several classes based on their basic structure. Flavonoids have the ability to control the accumulation of reactive oxygen species (ROS) via scavenger ROS when they are formed. Therefore, these antioxidant compounds have an important role in plant stress tolerance and a high relevance in human health, mainly due to their anti-inflammatory and antimicrobial properties. In addition, flavonoids have several applications in the food industry as preservatives, pigments, and antioxidants, as well as in other industries such as cosmetics and pharmaceuticals. However, flavonoids application for industrial purposes implies extraction processes with high purity and quality. Several methodologies have been developed aimed at increasing flavonoid extraction yield and being environmentally friendly. This review presents the most abundant natural flavonoids, their structure and chemical characteristics, extraction methods, and biological activity.

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Martono, Yohanes, Fidelia Novitasari et November Rianto Aminu. « Determination of Shelf Life of Herbal Products from the Combination of Stevia rebaudiana, Curcuma zanthorrhiza and Honey (Stekurmin MD) through the Accelerated Shelf Life Test (ASLT) Method ». Jurnal Kimia Sains dan Aplikasi 23, n^o 9 (7 septembre 2020) : 325–32. http://dx.doi.org/10.14710/jksa.23.9.325-332.

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Stekurmin MD is a syrup preparation formulated from the extract of Stevia rebaudiana leaves, temu lawak (Curcuma zanthorrhiza), and honey. One of the active compounds in Stekurmin MD products is phenolic and flavonoid compounds in which the active phenolic and flavonoid compounds can be degraded during the storage period. This study aimed to determine the shelf life of Stekurmin MD products based on the degradation of phenolic compounds and flavonoids. The Accelerated Shelf Life Test (ASLT) method was used in determining the shelf life kinetics of this product. Phenolic and flavonoid concentrations were determined using the UV-Vis spectrophotometric method with the gallic acid standard for phenolic and quercetin standard for flavonoids. Degradation of phenolic and flavonoid compounds was determined every 7 days during 35 days of storage at 25, 35, 45, and 55°C ± 2°C. In natural ingredients, there is a multi-mechanism reaction. The shelf life of Stekurmin MD products based on the degradation of phenolic and flavonoid active ingredients at room temperature were 39.909 days and 23.53 hours, respectively.

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Hasyim, Ummul Habibah, Fatma Sari, Ika Kurniaty et Annisya Ramadhani. « Effect of Ultrasonication Extraction Time on Determination of Flavonoid Levels in Ciplukan Plants ». Jurnal Bahan Alam Terbarukan 11, n^o 1 (20 juin 2022) : 33–36. http://dx.doi.org/10.15294/jbat.v11i1.35254.

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Ciplukan contains bioactive substances in the form of flavonoids, saponins, alkaloids, polyphenols, vitamin C, stearic acid, palmitic acid. Bioactive substances from natural ingredients are known to function as immunomodulators that can increase the body's immune system, activate the body's natural defenses and restore immune system imbalances. Immunomodulators are important in studies related to the issue of the coronavirus disease 19 (Covid-19) pandemic. The purpose of this study was to determine the effect of the extraction time on the ultrasonic method on the flavonoid yield of ciplukan plants using methanol as a solvent. The method used is ultrasonication extraction with a variable extraction time. The analysis was carried out by qualitative analysis using a solution of qursetin to determine the concentration of flavonoids. The results of the study obtained the optimum flavonoid concentration at the extraction time of 15 minutes

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Frazão, David F., Carlos Martins-Gomes, Jan L. Steck, Judith Keller, Fernanda Delgado, José C. Gonçalves, Mirko Bunzel, Cristina M. B. S. Pintado, Teresa Sosa Díaz et Amélia M. Silva. « Labdanum Resin from Cistus ladanifer L. : A Natural and Sustainable Ingredient for Skin Care Cosmetics with Relevant Cosmeceutical Bioactivities ». Plants 11, n^o 11 (31 mai 2022) : 1477. http://dx.doi.org/10.3390/plants11111477.

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Labdanum resin from Cistus ladanifer L. (Cistaceae) is an abundant natural resource in the Iberian Peninsula worth being explored in a sustainable manner. It is already used in the cosmetic industry; mainly by the fragrances/perfumery sector. However, given the highest market share and traditional uses, labdanum resin also has the potential to be used and valued as a cosmetic ingredient for skincare. Aiming to evaluate this potential, labdanum methanolic absolute and fractions purified by column chromatography were characterized by UPLC-DAD-ESI-MS and then evaluated for UV-protection, antioxidant, anti-elastase, anti-inflammatory, and antimicrobial activities. Labdanum absolute represented ~70% of the resin; diterpenoid and flavonoid fractions represented ~75% and 15% of the absolute, respectively. Labdane-type diterpenoids and methylated flavonoids were the main compounds in labdanum absolute and in diterpenoid and flavonoid fractions, respectively. Labdanum absolute showed a spectrophotometric sun protection factor (SPF) near 5, which is mainly due to flavonoids, as the flavonoids’ SPF was 13. Low antioxidant activity was observed, with ABTS radical scavenging being the most significant (0.142 ± 0.017, 0.379 ± 0.039 and 0.010 ± 0.003 mgTE/mgExt, for the absolute and flavonoid and terpene fractions, respectively). Anti-aging and anti-inflammatory activity are reported here for the first time, by the inhibition of elastase activity (22% and 13%, by absolute and flavonoid extract at 1 mg/mL), and by the inhibition of nitric oxide production in LPS-induced RAW 264.7 cells (84% to 98%, at 15 µg/mL extracts, flavonoid fraction the most active), respectively. Antimicrobial activity, against relevant skin and cosmetic product microorganisms, Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Escherichia coli, revealed that only S. aureus was susceptible to labdanum absolute (MIC: 1.2 mg/mL) and its fractions (MIC: <0.3 mg/mL). In conclusion, labdanum resin showed potential to be used in sunscreen cosmetics, anti-inflammatory skincare cosmeceuticals or medicines but has low potential as a cosmetic product preservative given the low antioxidant and low-spectrum antimicrobial activities.

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Mohos, Violetta, Eszter Fliszár-Nyúl et Miklós Poór. « Inhibition of Xanthine Oxidase-Catalyzed Xanthine and 6-Mercaptopurine Oxidation by Flavonoid Aglycones and Some of Their Conjugates ». International Journal of Molecular Sciences 21, n^o 9 (5 mai 2020) : 3256. http://dx.doi.org/10.3390/ijms21093256.

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Flavonoids are natural phenolic compounds, which are the active ingredients in several dietary supplements. It is well-known that some flavonoid aglycones are potent inhibitors of the xanthine oxidase (XO)-catalyzed uric acid formation in vitro. However, the effects of conjugated flavonoid metabolites are poorly characterized. Furthermore, the inhibition of XO-catalyzed 6-mercaptopurine oxidation is an important reaction in the pharmacokinetics of this antitumor drug. The inhibitory effects of some compounds on xanthine vs. 6-mercaptopurine oxidation showed large differences. Nevertheless, we have only limited information regarding the impact of flavonoids on 6-mercaptopurine oxidation. In this study, we examined the interactions of flavonoid aglycones and some of their conjugates with XO-catalyzed xanthine and 6-mercaptopurine oxidation in vitro. Diosmetin was the strongest inhibitor of uric acid formation, while apigenin showed the highest effect on 6-thiouric acid production. Kaempferol, fisetin, geraldol, luteolin, diosmetin, and chrysoeriol proved to be similarly strong inhibitors of xanthine and 6-mercaptopurine oxidation. While apigenin, chrysin, and chrysin-7-sulfate were more potent inhibitors of 6-mercaptopurine than xanthine oxidation. Many flavonoids showed similar or stronger (even 5- to 40-fold) inhibition of XO than the positive control allopurinol. Based on these observations, the extremely high intake of flavonoids may interfere with the elimination of 6-mercaptopurine.

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Kanakis, C. D., Sh Nafisi, Mehdi Rajabi, Azadeh Shadaloi, P. A. Tarantilis, M. G. Polissiou, J. Bariyanga et H. A. Tajmir-Riahi. « Structural analysis of DNA and RNA interactions with antioxidant flavonoids ». Spectroscopy 23, n^o 1 (2009) : 29–43. http://dx.doi.org/10.1155/2009/154321.

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Flavonoids are natural polyphynolic compounds with major antioxidant activity that can prevent DNA damage. The anticancer and antiviral activities of these natural products are attributed to their potential biomedical applications. In this review we are examining how the antioxidant flavonoids bind DNA and RNA and what mechanism of action is involved in preventing DNA damage. Detailed spectroscopic data on the interactions of morin (mor), apigenin (api), naringin (nar), quercetin (que), kaempferol (kae) and delphinidin (del) with DNA and transfer RNA in aqueous solution at physiological conditions were analysed. The structural analysis showed flavonoids mainly intercalate into DNA and RNA duplexes with minor external binding to the major or minor groove and the backbone phosphate group with overall binding constants for DNA adducts Kmor═5.99×103M–1, Kapi═7.10×104M–1, and Knar═3.10×103M–1, Kque═7.25×104M–1, Kkae═3.60×104M–1and Kdel═1.66×104M–1, and for tRNA adducts Kmor═9.15×103M–1, Kapi═4.96×104M–1, and Knar═1.14×104M–1, Kque═4.80×104M–1, Kkae═4.65×104M–1and Kdel═9.47×104M–1. The stability of adduct formation is in the order of que > api > kae > del >mor > nar for DNA and del > api > que > kae > nar > mor for tRNA. Low flavonoid concentration induces helical stabilization, whereas high pigment content causes helix opening. Flavonoids induce a partial B to A–DNA transition at high pigment concentration, while tRNA remains in A-family structure upon flavonoid complexation. The antioxidant activity of flavonoids changes in the order delphinidin > quercetin > kaempferol > morin > naringin > apigenin. The results show intercalated flavonoid molecule can act as an antioxidant and prevent DNA damage.

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Xu, Jia, Qin Shi, Yanan Wang, Yong Wang, Junbo Xin, Jin Cheng et Fang Li. « Recent Advances in Pharmaceutical Cocrystals : A Focused Review of Flavonoid Cocrystals ». Molecules 28, n^o 2 (6 janvier 2023) : 613. http://dx.doi.org/10.3390/molecules28020613.

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Cocrystallization is currently an attractive technique for tailoring the physicochemical properties of active pharmaceutical ingredients (APIs). Flavonoids are a large class of natural products with a wide range of beneficial properties, including anticancer, anti-inflammatory, antiviral and antioxidant properties, which makes them extensively studied. In order to improve the properties of flavonoids, such as solubility and bioavailability, the formation of cocrystals may be a feasible strategy. This review discusses in detail the possible hydrogen bond sites in the structure of APIs and the hydrogen bonding networks in the cocrystal structures, which will be beneficial for the targeted synthesis of flavonoid cocrystals. In addition, some successful studies that favorably alter the physicochemical properties of APIs through cocrystallization with coformers are also highlighted here. In addition to improving the solubility and bioavailability of flavonoids in most cases, flavonoid cocrystals may also alter their other properties, such as anti-inflammatory activity and photoluminescence properties.

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Gates, Paul J., et Norberto P. Lopes. « Characterisation of Flavonoid Aglycones by Negative Ion Chip-Based Nanospray Tandem Mass Spectrometry ». International Journal of Analytical Chemistry 2012 (2012) : 1–7. http://dx.doi.org/10.1155/2012/259217.

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Flavonoids are one of the most important classes of natural products having a wide variety of biological activities. There is wide interest in a range of medical and dietary applications, and having a rapid, reliable method for structural elucidation is essential. In this study a range of flavonoid standards are investigated by chip-based negative ion nanospray mass spectrometry. It was found that the different classes of flavonoid studied have a combination of distinct neutral losses from the precursor ion [M-H]−along with characteristic low-mass ions. By looking only for this distinct pattern of product ions, it is possible to determine the class of flavonoid directly. This methodology is tested here by the analysis of a green tea extract, where the expected flavonoids were readily identified, along with quercetin, which is shown to be present at only about 2% of the most intense ion in the spectrum.

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Wollenweber, Eckhard, Marion Dörr, Diego Rivera et James N. Roitman. « Externally Accumulated Flavonoids in Three Mediterranean Ononis Species ». Zeitschrift für Naturforschung C 58, n^o 11-12 (1 décembre 2003) : 771–75. http://dx.doi.org/10.1515/znc-2003-11-1202.

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Abstract The Mediterranean Ononis species, O. fruticosa, O. natrix subsp. ramosissima and O. tridentata, have been analyzed for their exudate flavonoids. More than 20 flavonoid aglycones were identified, some of which are rather rare natural compounds. One of them, namely hypolaetin- 8,3′,4′-trimethyl ether, had been found only once before. The results are presented in a table along with literature data, and the chemotaxonomic impact of the flavonoid patterns is discussed.

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Al-Jumaili, Mohammed Hadi Ali, et Muqdad Khairi Yahya Al hdeethi. « Study of Selected Flavonoid Structures and Their Potential Activity as Breast Anticancer Agents ». Cancer Informatics 20 (janvier 2021) : 117693512110551. http://dx.doi.org/10.1177/11769351211055160.

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Flavonoids contain pharmacological effects that help to protect cells from damage. However, the anticancer activity of flavonoids is related to their modulation of signal transduction pathways within cancer cells. Natural substances such as flavonoids have immune-stimulating anti-tumor effect that could lower breast cancer risk. However, various diseases included Alzheimer’s and cancer disease are associated with flavonoids intake due to their ability as antioxidant agent to alter essential cellular enzyme’s function. Therefore, through interaction between flavonoids and Cytochrome P450 (CYP) family enzymes led to make them chemopreventive agents for breast cancer. In this analysis, the chemo-informatics properties of 5 selective flavonoid derivatives and their efficiency as anti-breast cancer drugs were evaluated. Flavonoid ligands were docked with the predicted protein, which is human placental aromatase complexes with exemestane, a breast cancer drug (3S7S). Based on various docking energies, the molecular characteristics and bioactivity score of the following components, C15H12O6 2-(3,4-dihydroxyphenyl)-5,7-dihydroxy-2,3-dihydro-4H-chromen-4-one and C15H12O5 5,8-dihydroxy-2-(4-hydroxyphenyl)-2,3-dihydro-4H-chromen-4-one showed greatest molecular properties and bioactivity docking scores of −8.633117 and −8.633117 kcal/mol respectively. Therefore, both compounds could be considered antitumor agent.

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Yang, Yang, Xin Jin, Xinyi Jiao, Jinjing Li, Liuyi Liang, Yuanyuan Ma, Rui Liu et Zheng Li. « Advances in Pharmacological Actions and Mechanisms of Flavonoids from Traditional Chinese Medicine in Treating Chronic Obstructive Pulmonary Disease ». Evidence-Based Complementary and Alternative Medicine 2020 (31 décembre 2020) : 1–10. http://dx.doi.org/10.1155/2020/8871105.

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Chronic obstructive pulmonary disease (COPD) is a common respiratory disease with high morbidity and mortality. The conventional therapies remain palliative and have various undesired effects. Flavonoids from traditional Chinese medicine (TCM) have been proved to exert protective effects on COPD. This review aims to illuminate the poly-pharmacological properties of flavonoids in treating COPD based on laboratory evidences and clinical data and points out possible molecular mechanisms. Animal/laboratory studies and randomised clinical trials about administration of flavonoids from TCM for treating COPD from January 2010 to October 2020 were identified and collected, with the following terms: chronic obstructive pulmonary disease or chronic respiratory disease or inflammatory lung disease, and flavonoid or nature product or traditional Chinese medicine. Pharmacokinetic studies and external application treatment were excluded. A total of 15 flavonoid compounds were listed. Flavonoids could inhibit inflammation, oxidative stress, and cellular senescence, restore corticosteroid sensitivity, improve pulmonary histology, and boost pulmonary function through regulating multiple targets and signaling pathways, which manifest that flavonoids are a group of promising natural products for COPD. Nevertheless, most studies remain in the research phase of animal testing, and further clinical applications should be carried out.

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Mulyati, Budi, et Riong Seulina Panjaitan. « Studi Penambatan Molekul Flavonoid Pada Reseptor α-Glukosidase menggunakan PLANTS ». JURNAL KIMIA MULAWARMAN 18, n^o 2 (30 mai 2021) : 68. http://dx.doi.org/10.30872/jkm.v18i2.1004.

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ABSTRACT Plants that contain flavonoids are widely used in traditional medicine. Flavonoids can reduce blood glucose levels with their ability as anti-oxidants. The purpose of this study was to determine natural compounds from flavonoid derivatives that have good affinity and conformation and their interactions in inhibiting α-glucosidase (an enzyme that breaks down carbohydrates into glucose) and determine the sequence of ligands that interact more strongly with α protein / enzyme α-glucosidase. Molecular docking is a computational method that aims to imitate the interaction of a ligand molecule with the protein it targets in in-vitro tests. Molecular docking between flavonoids and α-glucosidase receptors was carried out using the PLANTS method to see its affinity. The flavonoids used as ligands were flavones, flavanols and chalcone with the results of the docking scores respectively, -65.41, -64.39 and -63.07 where the standard ligand used in this study was deoxynojirimycin (-77.12). In the active side of the α-Glucosidase enzyme that binds to flavonoid ligands is Gly 555, Glu 526 and Pro 556.

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Chen, Wang, Tan, Hu, Sundararajan et Zhou. « Profiling of Flavonoid and Antioxidant Activity of Fruit Tissues from 27 Chinese Local Citrus Cultivars ». Plants 9, n^o 2 (5 février 2020) : 196. http://dx.doi.org/10.3390/plants9020196.

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Flavonoid profile and antioxidant activity of citrus peels, pulps, and juices from 27 local citrus cultivars in China were investigated. Flavonoid composition and content were determined using UPLC-PDA. Total phenolic content (TPC) and total flavonoid content (TFC) were measured using a Folin–Ciocalteau reagent and Al(NO3)-NaNO2 complexometry, respectively. The antioxidant capacities of the extracts were evaluated by DPPH, ABTS and FRAP method, respectively. Citrus peel not only exhibited better antioxidant potential, but also presented more composition diversity and contained higher concentrations of flavonoids than pulp and juice. Different citrus species were characterized by their individual predominant flavonoids, contributing largely to the antioxidant activity, such as mandarin was characterized by hesperidin, nobiletin and tangeretin, while pummelo and papeda were characterized by naringin. The peel of Guihuadinanfeng (Citrus reticulata) had the highest TPC of 23.46 mg equivalent gallic acid/g DW (dry weight) and TFC of 21.37 mg equivalent rutin/g DW. Shiyueju (C. reticulata) peel showed the highest antioxidant capacity based on the antioxidant potency composite (APC) analysis. Overall, mandarin (C. reticulata) fruits peel contained more TPC and TFC, exhibiting higher antioxidant capacities than other species, and were good natural sources of flavonoids and antioxidants.

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Nguyen, Khanh-Hung, Phuong-Linh Pham, Bao-Khanh Lo Thi, Xuan-Phong Ong, Thi-Thuong Ngo, Kim-Dung Le et Viet-Hong La. « Research on flavonoids collection, activity assay and initial steps to create tea from Camellia tamdaoensis Hakoda et Ninh ». Tạp chí Khoa học - Trường Đại học Sư phạm Hà Nội 2 1, n^o 2 (28 décembre 2022) : 24–31. http://dx.doi.org/10.56764/hpu2.jos.2022.1.2.23-31.

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The Camellia tamdaoensis Hakoda et Ninh contains many useful phenolic compounds for human health, among them, flavonoids showed many biological activities such as antibacterial, anti-inflammatory. In this study, we used the recovery extract method to collect concentrated solutions with high flavonoid content from golden tea leaves, in which ethanol served as solvents at the temperature of 70°C for 1 hour . The high golden tea leaves showed good antibacterial properties with Gram (+), Gram (-) and fungi, demonstrate toxicity to HEPG2 liver cancer cell line with IC50 100 ± 2.77 µg/ml. The process of creating tea bags from golden tea leaves with flavonoid supplements was completed. The ground golden tea leaves were sprayed with a solution containing flavonoids from 0.33 - 0.67 mg extract per extract grams of golden leaves, then dry until reaching a constant mass at 50°C. The product finally was packed into filter bags and investigated in terms of the quality of taste and color according to TCVN 3218: 2012. The flavonoid content in this product was 1.6 times higher than that of natural materials. This research’s results show the potential to develop golden tea products containing high flavonoids in the future.

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Wollenweber, Eckhard, et James N. Roitman. « C-Methyl Flavones from the Leaf Wax of Leptospermum laevigatum (Myrtaceae) ». Zeitschrift für Naturforschung C 51, n^o 1-2 (1 février 1996) : 8–10. http://dx.doi.org/10.1515/znc-1996-1-203.

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Abstract Flavonoid aglycones were detected as minor constituents of the leaf wax of the Myrtaceae Leptosperm um laevigatum. They belong to the rarely encountered C-methyl flavonoids. One of them is a new natural product, 5-hydroxy-3,7,3′,4′-tetramethoxy-6-C-methyl flavone.

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Wollenweber, Eckhard, Rüdiger Wehde, Matthias Christ et Marion Dörr. « Surface Flavonoids in Catalpa Ovata, Greyia Sutherlandii and Paulownia Tomentosa ». Natural Product Communications 3, n^o 8 (août 2008) : 1934578X0800300. http://dx.doi.org/10.1177/1934578x0800300810.

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Exudate flavonoids have been found on the green fruits of Catalpa ovata (Bignoniaceae) and Paulownia tomentosa (Scrophulariaceae) and on the leaf surfaces of Greyia sutherlandii (Melianthaceae) and Paulownia tomentosa, respectively. The flavonoid aglycones are mostly flavone and flavonol methyl ethers, including some rare natural products. Several flavanones and 2 dihydrochalcones have also been detected, the flavanones produced by Paulownia being geranylated products. The occurrence of exudate flavonoids on fruit tissue has been rarely noticed in the past.

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Vinogradova, Yulia, Olga Shelepova, Olena Vergun, Olga Grygorieva et Jan Brindza. « Phenolic content and antioxidant activity of Echinocystis lobata (Mich.) Torr. ET Gray (Cucurbitaceae) ». Potravinarstvo Slovak Journal of Food Sciences 15 (13 septembre 2021) : 784–91. http://dx.doi.org/10.5219/1579.

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Echinocystis lobata (Mich.) Torr. et Gray extracts were investigated for their bioactive compounds and their potential for natural antioxidant properties. In vitro antioxidant activity of methanol, ethanol, and water extracts were evaluated by 1,1-diphenyl-picrylhydrazyl (DPPH) radical scavenging activity. Total phenolic content (TPC) and total flavonoid content (TFC) of fruits and seeds were determined. TPC is a fairly constant value and varies weakly both among the different organs of Echinocystis lobata and among the geographical locations of the populations studied. Like other invasive species, Echinocystis lobata is superior to many other plants in terms of the total amount of flavonoids contained in its fruits and seeds. The dried fruits contain more flavonoids than the seeds. Seeds from Slovak populations have higher flavonoid content than those from Russian populations. The results demonstrated that Echinocystis lobata can be a good source of natural antioxidants and have a great potential for commercialization, especially in the pharmaceutical industry.

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Alhadrami, Hani A., Raha Orfali, Ahmed A. Hamed, Mohammed M. Ghoneim, Hossam M. Hassan, Ahmed S. I. Hassane, Mostafa E. Rateb, Ahmed M. Sayed et Noha M. Gamaleldin. « Flavonoid-Coated Gold Nanoparticles as Efficient Antibiotics against Gram-Negative Bacteria—Evidence from In Silico-Supported In Vitro Studies ». Antibiotics 10, n^o 8 (12 août 2021) : 968. http://dx.doi.org/10.3390/antibiotics10080968.

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Flavonoids are a class of bioactive plant-derived natural products that exhibit a broad range of biological activities, including antibacterial ones. Their inhibitory activity toward Gram-positive bacterial was found to be superior to that against Gram-negative ones. In the present study, a number of flavonoid-coated gold nanoparticles (GNPs) were designed to enhance the antibacterial effects of chrysin, kaempferol, and quercetin against a number of Gram-negative bacteria. The prepared GNPs were able to conjugate to these three flavonoids with conjugation efficiency ranging from 41% to 80%. Additionally, they were able to exert an enhanced antibacterial activity in comparison with the free flavonoids and the unconjugated GNPs. Quercetin-coated GNPs were the most active nano-conjugates and were able to penetrate the cell wall of E. coli. A number of in silico experiments were carried out to explain the conjugation efficiency and the antibacterial mechanisms of these flavonoids as follows: (i) these flavonoids can efficiently bind to the glutathione linker on the surface of GNPs via H-bonding; (ii) these flavonoids, particularly quercetin, were able to increase the bacterial membrane rigidity, and hence decrease its functionality; (iii) these flavonoids can inhibit E. coli’s DNA gyrase (Gyr-B) with IC50 values ranging from 0.9 to 3.9 µM. In conclusion, these bioactive flavonoid-based GNPs are considered to be very promising antibiotic candidates for further development and evaluation.

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Dhahir, Saadiyah A., et Ameera H. Hamed. « IDENTIFICATION OF FLAVONOIDS IN IRAQI HONEY AND COMPARISON WITH OTHERS KIND BY HIGH PERFORMANCE LIQUID CHROMATOGRAPHY WITH UV DETECTION ». International Journal of Research -GRANTHAALAYAH 5, n^o 4 (30 avril 2017) : 162–75. http://dx.doi.org/10.29121/granthaalayah.v5.i4.2017.1809.

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Honey is rich in phenolic acids and flavonoids, which exhibit a wide range of biological effects and act as natural antioxidants. The analysis of polyphenols has been regarded as a very promising way of studying floral and geographical origins of honeys. The aim of this study was to determine, flavonoid in honey samples collected from different region in Iraq and Comparison with others kind. The flavonoids which measured in honey samples are (Myricetin, Quercetin, Hesperdin, Naringenin, Apigenin, Kaempferol, Chrisin). Chromatographic Separation was performed using a reversed phase column C18 and acetonitrile 60% (v/v) flow rate 1.0 ml/min, pH 5.5 at 280 nm. All calibration curves of the flavonoid compounds showed good linearity (r -0.9999) within the test range. Concentration of flavonoids ranged from Myricetin (1.903- 18.5) mg/kg, Quercetin (3.31-22.01) mg/kg, Hesperdin (4.55-16.2) mg/kg, Naringenin (3.2-24.68) mg/kg, Apigenin (6.76-28.81) mg/kg, Kaempferol (3.31-38.13) mg/kg, Chrisin (2.0-28.0) mg/kg respectively.

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Kistriyani, Lilis, Annisa Alvi Ramadhani et Dika Puji Resphaty. « Encapsulation of Anthocyanin and Flavonoid from Watermelon Rind (Citrullus lanatus) as a Natural Food Preservative ». Key Engineering Materials 818 (août 2019) : 50–55. http://dx.doi.org/10.4028/www.scientific.net/kem.818.50.

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Special Region of Yogyakarta is one of the regions that has high potential for natural disasters. Food is the most consumable material which is needed when natural disasters occur. An alternative form of food preservative is needed to maintain nutritious foods that will be distributed to the victims of natural disasters. The foods must still appropriate to eat. In this research, watermelon rind was chosen as an ingredient to make natural preservatives because they contain flavonoids and anthocyanins. This research aims were to determine the total content of anthocyanins, flavonoids and phenolics in the red watermelon rind and yellow watermelon rind, also to determine the effect of chitosan composition to the ability of flavonoids and phenolics release in the food. This research was carried out by extraction and encapsulation methods. The analysis included the content of Total Anthocyanin (TA), Total Flavonoids (TF) and Total Phenolic (TPC) in the supernatant. The other analysis was in vitro tests that was done to know the ability of flavonoids and phenolics release in the food. The total anthocyanin content in the red watermelon rind was 0.0334 mg L-1 while in the yellow watermelon rind was 0.0668 mg L-1. The total content of flavonoids in the red watermelon rind was 0.7369 g mL-1, while in the yellow watermelon rind was 0.3296 g mL-1. The total phenolic content of red watermelon rind was 0.3669 g mL-1, while in the yellow watermelon rind was 0.2273 g mL-1. In both of red and yellow watermelon rind, the highest release of flavonoid and phenolic levels showed in the variations of chitosan mass 0.4 grams. The highest flavonoid content released was 0.0638 g mL-1 in red watermelon rind and 0.0702 g mL-1 in yellow watermelon rind. The highest phenolic content released was 0.0321 g mL-1 in red watermelon rind and 0.0408 g mL-1 in yellow watermelon rind.

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Khater, Mai, Divyashree Ravishankar, Francesca Greco et Helen MI Osborn. « Metal complexes of flavonoids : their synthesis, characterization and enhanced antioxidant and anticancer activities ». Future Medicinal Chemistry 11, n^o 21 (novembre 2019) : 2845–67. http://dx.doi.org/10.4155/fmc-2019-0237.

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Flavonoids are polyphenolic compounds of natural origin. They are extensively studied within drug discovery programs due to their wide ranging biological activities such as antimicrobial, antioxidant, antitumor, neuroprotective and cardioprotective properties. The ability of flavonoids to coordinate with metal atoms has provided new leads for drug discovery programs, with better pharmacological activities and clinical profiles than the parent flavonoids. In this review, the enhanced antioxidant and anticancer activities of flavonoid metal complexes versus the parent flavonoids are discussed. Possible mechanisms of action for the metal complexes, such as DNA binding and apoptosis induction, are also presented alongside an overview of the synthesis of the metal complexes, and the different techniques used for their characterization.

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Wollenweber, Eckhard, et James N. Roitman. « New Frond Exudate Flavonoids From Cheilanthoid Ferns ». Zeitschrift für Naturforschung C 46, n^o 5-6 (1 juin 1991) : 325–30. http://dx.doi.org/10.1515/znc-1991-5-601.

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A series of new flavonoid aglycones have been identified in the frond exudates of the fern Cheilanthes argentea, in five species of Notholaena, in Pityrogramma triangularis, and in Platyzoma microphylla. These aglycones comprise several rare flavonoids and five novel natural products: 5,7,8-trihydroxy-3-methoxy-6-methyl flavone, 3,5,2′-trihydroxy-7,8,4′-trimethoxy flavone, 5,2′-dihydroxy-3,7,8-trimethoxy flavone, 5,7,4′-trihydroxy-2′-methoxy flavanone, and 3,5,4′-trihydroxy-6,7,8-trimethoxy flavone. The novel flavonoids were characterized by their N M R spectral data

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Hou, Jiaqi, Yuhan Zhou, Liping Ran, Yanzhu Chen, Ting Zhang, Bowei Sun, Yimo Yang, Qianzi Sang et Li Cao. « Transcriptome and Metabolome Analysis Reveal the Flavonoid Biosynthesis Mechanism of Abelmoschus manihot L. at Different Anthesis Stages ». Metabolites 13, n^o 2 (1 février 2023) : 216. http://dx.doi.org/10.3390/metabo13020216.

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Abelmoschus manihot L. (HSK) is a rare and endangered species in the wild that grows on the cliffs of deep mountains. As a natural plant, the chemical composition of HSK is relatively complex, which mainly includes flavonoids, organic acids, polysaccharides, and various trace elements with good effects of clearing away heat, anti-inflammatory, analgesic, and calming nerves, and inhibiting tumor cells. In this experiment, different developmental stages of HSK flowers were used for optimization of the flavonoid extraction and determining method. The antioxidant activities, flavonoid accumulation pattern, and synthesis regulatory network were analyzed using biochemistry, RNA-seq, and UPLC-MS/MS. The total content of flavonoids, vitexin rhamnoside, hyperoside, and rutin in HSK flowers at T3 stage (flower wilting) was significantly higher than in T2 (full flowering) and T1 (bud) stages. Compared with T1 and T2, the antioxidant capacity of the T3 flower alcohol extract was also the strongest, including the total reducing ability, DPPH clearance, OH clearance, O2− clearance, and total antioxidant capacity. A total of 156 flavonoids and 47,179 unigenes were detected by UPLC-MS/MS and RNA-Seq, respectively. The candidate genes and key metabolites involved in flavonoid biosynthesis were identified and the regulatory networks were also analyzed in this study. qRT-PCR test further proved that the gene expression level was consistent with the results of RNA sequence data. The relationship between the gene expression and flavonoid accumulation network provides a theoretical basis for the mining and regulation of functional genes related to the flavonoid biosynthesis and metabolism in Abelmoschus manihot L.

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Kejík, Zdeněk, Robert Kaplánek, Michal Masařík, Petr Babula, Adam Matkowski, Petr Filipenský, Kateřina Veselá et al. « Iron Complexes of Flavonoids-Antioxidant Capacity and Beyond ». International Journal of Molecular Sciences 22, n^o 2 (11 janvier 2021) : 646. http://dx.doi.org/10.3390/ijms22020646.

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Flavonoids are common plant natural products able to suppress ROS-related damage and alleviate oxidative stress. One of key mechanisms, involved in this phenomenon is chelation of transition metal ions. From a physiological perspective, iron is the most significant transition metal, because of its abundance in living organisms and ubiquitous involvement in redox processes. The chemical, pharmaceutical, and biological properties of flavonoids can be significantly affected by their interaction with transition metal ions, mainly iron. In this review, we explain the interaction of various flavonoid structures with Fe(II) and Fe(III) ions and critically discuss the influence of chelated ions on the flavonoid biochemical properties. In addition, specific biological effects of their iron metallocomplexes, such as the inhibition of iron-containing enzymes, have been included in this review.

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Kejík, Zdeněk, Robert Kaplánek, Michal Masařík, Petr Babula, Adam Matkowski, Petr Filipenský, Kateřina Veselá et al. « Iron Complexes of Flavonoids-Antioxidant Capacity and Beyond ». International Journal of Molecular Sciences 22, n^o 2 (11 janvier 2021) : 646. http://dx.doi.org/10.3390/ijms22020646.

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Flavonoids are common plant natural products able to suppress ROS-related damage and alleviate oxidative stress. One of key mechanisms, involved in this phenomenon is chelation of transition metal ions. From a physiological perspective, iron is the most significant transition metal, because of its abundance in living organisms and ubiquitous involvement in redox processes. The chemical, pharmaceutical, and biological properties of flavonoids can be significantly affected by their interaction with transition metal ions, mainly iron. In this review, we explain the interaction of various flavonoid structures with Fe(II) and Fe(III) ions and critically discuss the influence of chelated ions on the flavonoid biochemical properties. In addition, specific biological effects of their iron metallocomplexes, such as the inhibition of iron-containing enzymes, have been included in this review.

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Dou, Fangmin, Zhi Wang, Guiying Li et Baoqing Dun. « Microbial Transformation of Flavonoids by Isaria fumosorosea ACCC 37814 ». Molecules 24, n^o 6 (15 mars 2019) : 1028. http://dx.doi.org/10.3390/molecules24061028.

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Glycosylation is an efficient strategy to modulate the solubility, stability, bioavailability and bioactivity of drug-like natural products. Biological methods, such as whole-cell biocatalyst, promise a simple but highly effective approach to glycosylate biologically active small molecules with remarkable regio- and stereo-selectivity. Herein, we use the entomopathogenic filamentous fungus Isaria fumosorosea ACCC 37814 to biotransform a panel of phenolic natural products, including flavonoids and anthraquinone, into their glycosides. Six new flavonoid (4-O-methyl)glucopyranosides are obtained and structurally characterized using high resolution mass and nuclear magnetic resonance spectroscopic techniques. These compounds further expand the structural diversity of flavonoid glycosides and may be used in biological study.

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Khalid, Muhammad Nouman. « An In-Depth Review of Flavonoid Profile in Cotton (Gossypium hirsutum L.) ». Indian Journal of Pure & ; Applied Biosciences 9, n^o 3 (30 juin 2021) : 202–16. http://dx.doi.org/10.18782/2582-2845.8721.

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Being economically important for natural fiber, seed cotton and protein, cotton demand is increasing rapidly. With the ever-growing population, there is an ultimate need to increase the cotton production to meet this demand of man and livestock. Different Flavonoids, which are compounds that have antioxidant properties, serve an essential role in sustaining plant function and health. Flavonoids operate largely as photo protectors and phytoalexins, influencing the phytohormone auxin transport that affects the plant structure. Cotton production is also linked to the flavonoids as they play a great role in plant protection and vigor. Flavonoids play a critical role in response to abiotic stress. Leaf reddening in cotton and fungal infection resistance is attributed the flavonoids. Flavonoids also take part in the development of fiber and its color, maintenance of plant health and it’s defensive mechanism. With an increasing interest in the biological functions of flavonoids as well as advancements in isolation and classification techniques over the last two decades, the numerous flavonoids known in the cotton plant have risen dramatically. The capacity to regulate flavonoid expression in plants offers a chance to change defense mechanisms and growth. Genetic engineering techniques offer different methods that improves certain characteristics of cotton to further boost its output. This study aims to summarize existing findings on the prevalence and dispersal of flavonoids in cotton as well as to examine the historical research on flavonoids in cotton as well as potential paths for future research on this plant species. This review enlists the flavonoid profile studied by many scientists in the past and their distribution in cotton plant which consist of 52 flavonoids divided into 7 groups.

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Widiyana, Anita Puspa. « Validasi dari Spektrofotometri UV-Vis dan Kandungan Total Flavonoid Ekstrak Etanol dari Akar Alang-Alang (Imperata cylindrica) dan Daun Pegagan (Centella asiatica) Anita Puspa Widiyana ». Journal of Pharmaceutical Care Anwar Medika 3, n^o 2 (30 juin 2021) : 126–36. http://dx.doi.org/10.36932/jpcam.v3i2.69.

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Validation as a quality control for the content of chemical compounds from natural ingredients. One of the chemical constituents is the flavonoids which are found in the Imperatacylindrica roots and Centella asiatica leaves. This study aims to ensure the analysis method meets the requirements and determines the levels of flavonoids. The research stages included extraction, validation and determination of total flavonoid. Extraction was carried out by immersing dry simplicia in 96% ethanol solvent for 3x24 hours. The solvent is evaporated using a rotary evaporator until a thick extract is formed. Validation testing includes linearity, accuracy, precision, LOD and LOQ. Determinationof the total flavonoid was carried out by measuring the absorption at a maximum wavelength of 428.2 nm. The validation results includethe correlation coefficient (R) of 0.998, precision % RSD <2 %, %accuracy 99,53-97,98%, LOD 3.02ppm and LOQ 9.15 ppm. The total flavonoid of the ethanol extract of Imperata cylindrica roots was 36.39 ± 0.08 mg/g QE and Centella asiatica leaves was 102.10 ± 0.08 mg/g QE. The conclusion is that the method used met the validation requirements and the total flavonoid content of the ethanol extract of Centella asiatica leaves was higher than Imperata cylindrica roots

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Nasruddin, Nina Indriyani, Novi Silvia Hardiany et Wiji Lestari. « Flavonoid intake and its correlation to malondialdehyde serum among reproductive-aged women with obesity ». World Nutrition Journal 5, n^o i2 (28 février 2022) : 8–17. http://dx.doi.org/10.25220/wnj.v05.i2.0003.

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Background: Obesity modulates oxidative stress and can be detected by examining malondialdehyde (MDA) serum levels. Flavonoids are natural bioactive ingredients that can be found in various types of vegetables and fruits that function as antioxidants to suppress that oxidative stress. Objective: This study aimed to determine the correlation between flavonoid intake and MDA serum levels in obese women of reproductive age. Methods: This cross-sectional study was conducted in Kendari, Indonesia from April to October 2021. The purposive sampling method was used to obtain 88 subjects who met the research criteria. Data were collected through interviews covering flavonoids intake using validated SQ-FFQ. Anthropometric measurements were performed to assess nutritional status, and laboratory tests were applied to determine MDA serum levels. Results: The average intake of flavonoids in the subjects was 142,26 ± 56,53 mg per day. Meanwhile, the average MDA serum level in the subjects was 2.16 mol/L, ranging from 1.09 nmol/ml to 6.71 nmol/ml. There was no significant correlation between total flavonoid intake and MDA serum levels in obese women of reproductive age (r=0,188, p=0,079). However, there was a weak correlation between the intake of flavonoid subclasses, namely flavan-3-ols/flavanols and MDA serum levels (r=0.325, p=0.002). Conclusion: We conclude that there was no correlation between total flavonoid intake and MDA serum levels. However, there was a correlation between flavan-3-ols/flavanols and MDA serum levels in the subjects.

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Wollenweber, Eckhard, Yoshinori Asakawa, Detlef Schillo, Ulrich Lehmann et Heidrun Weigel. « A Novel Caffeic Acid Derivative and Other Constituents of Populus Bud Excretion and Propolis (Bee-Glue) ». Zeitschrift für Naturforschung C 42, n^o 9-10 (1 octobre 1987) : 1030–34. http://dx.doi.org/10.1515/znc-1987-9-1004.

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Abstract The bud exudates of Populus nigra, P. trichocarpa, and P. grandidentata × tremuloides were analyzed for the presence of phenolics and flavonoids. A novel natural product, caffeic acid y.y-dimethylallyl ester, was identified from P. nigra, along with further phenolics such as ρ-hydroxy-acetophenone, dimethyl caffeic acid, cinnamoyl cinnamata and vanillin. The flavonoid aglycones correspond to those reported earlier. Propolis samples from the Sonoran Desert were shown to exhibit the flavonoid pattern that is typical for poplar bud exudates, thus confirming this material as the major source for bee-glue. Only a single flavonoid might originate from the leaf exudate of a desert shrub.

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