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Quercetin

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https://www.readbyqxmd.com/read/28644504/a-structural-mechanism-of-flavonoids-in-inhibiting-serine-proteases
#1
Guangpu Xue, Lihu Gong, Cai Yuan, Mingming Xu, Xu Wang, Longguang Jiang, Mingdong Huang
Quercetin is a member of the flavonoids and was previously demonstrated to inhibit trypsin-like serine proteases at micromolar potencies. Different molecular models were proposed to explain such inhibition. However, controversies remain on the molecular details of inhibition. Here, we report the X-ray crystal structure of quercetin in a complex with the urokinase-type plasminogen activator (uPA), an archetypical serine protease. The structure showed that quercetin binds to the specific substrate binding pocket (S1 pocket) of uPA mainly through its two neighboring phenolic hydroxyl groups...
June 23, 2017: Food & Function
https://www.readbyqxmd.com/read/28644409/quercetin-protects-obesity-induced-hypothalamic-inflammation-by-reducing-microglia-mediated-inflammatory-responses-via-ho-1-induction
#2
Jihyeon Yang, Chu-Sook Kim, Thai Hien Tu, Min-Seon Kim, Tsuyoshi Goto, Teruo Kawada, Myung-Sook Choi, Taesun Park, Mi-Kyung Sung, Jong Won Yun, Suck-Young Choe, Jee Hye Lee, Yeonsoo Joe, Hye-Seon Choi, Sung Hoon Back, Hun Taeg Chung, Rina Yu
Obesity-induced hypothalamic inflammation is characterized by activation of microglia, which are resident macrophages of the central nervous system, and is implicated in the derangement of energy homeostasis, metabolic complications, and neurodegenerative diseases. Quercetin, a naturally occurring flavonoid, is known to protect against oxidative stress and inflammation-related metabolic complications. Here, we demonstrate that quercetin reduces obesity-induced hypothalamic inflammation by inhibiting microglia-mediated inflammatory responses, and the beneficial action of quercetin is associated with heme oxygenase (HO-1) induction...
June 23, 2017: Nutrients
https://www.readbyqxmd.com/read/28644391/molecular-structure-affinity-relationship-of-flavonoids-in-lotus-leaf-nelumbo-nucifera-gaertn-on-binding-to-human-serum-albumin-and-bovine-serum-albumin-by-spectroscopic-method
#3
Xiaosheng Tang, Ping Tang, Liangliang Liu
Lotus leaf has gained growing popularity as an ingredient in herbal formulations due to its various activities. As main functional components of lotus leaf, the difference in structure of flavonoids affected their binding properties and activities. In this paper, the existence of 11 flavonoids in lotus leaf extract was confirmed by High Performance Liquid Chromatography (HPLC) analysis and 11 flavonoids showed various contents in lotus leaf. The interactions between lotus leaf extract and two kinds of serum albumins (human serum albumin (HSA) and bovine serum albumin (BSA)) were investigated by spectroscopic methods...
June 23, 2017: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
https://www.readbyqxmd.com/read/28642704/quercetin-a-lead-compound-against-type-2-diabetes-ameliorates-glucose-uptake-via-ampk-pathway-in-skeletal-muscle-cell-line
#4
R Dhanya, A D Arya, P Nisha, P Jayamurthy
Herein we investigated the molecular mechanism of action of the citrus flavonoid, quercetin in skeletal muscle cells (L6 myotubes). Taking advantage of protein kinase inhibitors, we proved that the effect of quercetin on 2-NBDG uptake in L6 myotubes was not through insulin signaling pathway, but through adenosine monophosphate kinase (AMPK) pathway and its downstream target p38 MAPK. An increase in the cellular AMP to ATP ratio on pretreatment may account for AMPK activation which was coupled with a transient change in mitochondrial membrane potential...
2017: Frontiers in Pharmacology
https://www.readbyqxmd.com/read/28640339/special-metabolites-isolated-from-urochloa-humidicola-poaceae
#5
Débora R DE Oliveira, Delci D Nepomuceno, Rosane N Castro, Raimundo Braz, Mário G DE Carvalho
This study aims to identify special metabolites in polar extracts from Urochloa humidicola (synonym Brachiaria humidicola) that have allelopathic effects and induce secondary photosensitization in ruminants. The compounds were isolated and identified via chromatographic and spectroscopic techniques. The compounds 4-hydroxy-3-methoxy-benzoic acid, trans-4-hydroxycinnamic acid, and p-hydroxy-benzoic acid; the flavonols isorhamnetin-3-O-β-d-glucopyranoside and methyl quercetin-3-O-β-d-glucuronate; and kaempferitrin, quercetin-3-O-α-l-rhamnopyranoside, and tricin were identified in the extract from the leaves of Urochloa humidicola...
April 2017: Anais da Academia Brasileira de Ciências
https://www.readbyqxmd.com/read/28640307/healthy-properties-of-green-and-white-teas-an-update
#6
REVIEW
S Pastoriza, M Mesías, C Cabrera, J A Rufián-Henares
Green tea has been consumed for centuries in Japan, China and Morocco. White tea, which is considered a variety of green tea, is mostly consumed in China and is very appreciated for its flavor. Currently the consumption of both types of tea has been extended to the western countries even as a functional ingredient. A group of polyphenols called catechins stands out among their bioactive components, the most abundant being the (-) epigallocatechin gallate, with high antioxidant power. Teas also contain other phenolic compounds such as gallic, caffeic, chlorogenic or cinnamic acids, quercetin and proanthocyanidols, caffeine, theophylline, l-theanine and minerals such as fluorine, manganese or chromium...
June 22, 2017: Food & Function
https://www.readbyqxmd.com/read/28639379/the-in-vitro-and-in-vivo-biological-activities-of-the-leaf-of-cape-myrtle-myrsine-africana-l
#7
Hina Gul, Mushtaq Ahmad, Muhammad Zafar, M Shareez Ahmad, AmbreenAbid, Syeda Hira, Imam Shah, Muhammad Gulfraz
The cape myrtle, Myrsine africana L., is a widely used medicinal plant, which has not been well investigated. We assessed the in vivo hepatoprotective and in vitro antiproliferative and antioxidant effects of leaf extracts of M. africana chemically profiled using high-performance liquid chromatography. Three flavonoids were quantified, and gas chromatography-mass spectrometry analysis revealed the presence of common fatty acids. The animal study was conducted on mice treated with CCl4, using three doses each of the methanol and chloroform extract (100, 200 and 300 mg/kg b...
June 22, 2017: Phytotherapy Research: PTR
https://www.readbyqxmd.com/read/28638888/modulation-of-key-biochemical-markers-relevant-to-stroke-by-antiaris-africana-leaf-extract-following-cerebral-ischemia-reperfusion-injury
#8
Omotayo B Ilesanmi, Afolabi C Akinmoladun, Olanrewaju Sam Olayeriju, Ibrahim Olabayode Saliu, M Tolulope Olaleye, Afolabi A Akindahunsi
BACKGROUND: Oxidative stress plays a significant role in stroke pathogenesis. Hence, plants rich in antioxidant phytochemicals have been suggested as effective remedies for prevention and treatment of stroke and other neurological diseases. Antiaris africana Engl. (Moraceae) is traditionally used for the management of brain-related problems but there is paucity of data on its anti-stroke potential. MATERIALS AND METHODS: Ischemia/reperfusion injury was induced by a 30 min bilateral common carotid artery occlusion/ 2 h reperfusion (BCCAO/R) in the brain of male Wistar rats...
2017: African Journal of Traditional, Complementary, and Alternative Medicines: AJTCAM
https://www.readbyqxmd.com/read/28636950/structural-evidence-of-quercetin-multi-target-bioactivity-a-reverse-virtual-screening-strategy
#9
Diego Carvalho, Margot Paulino, Fabio Polticelli, Florencia Arredondo, Robert J Williams, Juan A Abin-Carriquiry
The ubiquitous flavonoid quercetin is broadly recognized for showing diverse biological and health-promoting effects, such as anti-cancer, anti-inflammatory and cytoprotective activities. The therapeutic potential of quercetin and similar compounds for preventing such diverse oxidative stress-related pathologies has been generally attributed to their direct antioxidant properties. Nevertheless, accumulated evidence indicates that quercetin is also able to interact with multiple cellular targets influencing the activity of diverse signaling pathways...
June 18, 2017: European Journal of Pharmaceutical Sciences
https://www.readbyqxmd.com/read/28636279/effects-of-in-ovo-injection-of-chrysin-quercetin-and-ascorbic-acid-on-hatchability-somatic-attributes-hepatic-oxidative-status-and-early-post-hatch-performance-of-broiler-chicks
#10
F Khaligh, A Hassanabadi, H Nassiri-Moghaddam, A Golian, G-A Kalidari
An experiment was conducted to evaluate the effects of in ovo injection of chrysin, quercetin and ascorbic acid on hatchability, somatic attributes, hepatic antioxidant status and early post-hatch growth performance of broiler chicks. Four hundred and eighty embryonated broiler breeder eggs containing live 18-day-old embryos were divided into six groups of 80 eggs each. One group remained intact and served as a control group (i), whereas the other five groups were injected with the prepared injection solutions as follows: (ii) 0...
June 21, 2017: Journal of Animal Physiology and Animal Nutrition
https://www.readbyqxmd.com/read/28635261/novel-protein-based-solid-biosensor-for-determining-pro-oxidant-activity-of-phenolic-compounds
#11
Esin Akyüz, Kevser Sözgen Başkan, Esma Tütem, Reşat Apak
To develop a protein‒based biosensor measuring the pro-oxidant activities of phenolic compounds, egg white proteins were precipitated with calcium chloride to obtain an insoluble calcium proteinate complex. This biosensor was used for the determination of Cu(II)‒induced pro-oxidant activity of antioxidants such as gallic acid, catechin, epicatechin, quercetin, chlorogenic acid and myricetin, and ascorbic acid. This assay involved the reduction of Cu(II) ions to Cu(I) by antioxidant compounds (simultaneously giving rise to reactive oxygen species) and binding of the formed Cu(I) to the solid biosensor...
June 21, 2017: Journal of Agricultural and Food Chemistry
https://www.readbyqxmd.com/read/28634125/metabolic-engineering-of-yeast-for-fermentative-production-of-flavonoids
#12
Angelica Rodriguez, Tomas Strucko, Steen Gustav Stahlhut, Mette Kristensen, Daniel Killerup Svenssen, Jochen Forster, Jens Nielsen, Irina Borodina
Yeast Saccharomyces cerevisiae was engineered for de novo production of six different flavonoids (naringenin, liquiritigenin, kaempferol, resokaempferol, quercetin, and fisetin) directly from glucose, without supplementation of expensive intermediates. This required reconstruction of long biosynthetic pathways, comprising up to eight heterologous genes from plants. The obtained titers of kaempferol 26.57±2.66mgL(-1) and quercetin 20.38±2.57mgL(-1) exceed the previously reported titers in yeast. This is also the first report of de novo biosynthesis of resokaempferol and fisetin in yeast...
June 12, 2017: Bioresource Technology
https://www.readbyqxmd.com/read/28633497/genome-wide-identification-and-functional-characterization-of-udp-glucosyltransferase-genes-involved-in-flavonoid-biosynthesis-in-glycine-max
#13
Qinggang Yin, Guoan Shen, Shaokang Di, Cunying Fan, Zhenzhan Chang, Yongzhen Pang
Flavonoids, natural products abundant in the model legume Glycine max, confer benefits to plants and animals health. Flavonoids are present in soybean mainly as glycoconjugates. However, the biosynthesis mechanisms of flavonoid glycosides are largely unknown in G. max. In the present study, 212 putative UDP-glycosyltransferase (UGTs) genes were identified in G. max by genome-wide searching. The GmUGT genes were distributed differentially among the twenty chromosomes, and they were expressed in various tissues with distinct expression profile...
June 19, 2017: Plant & Cell Physiology
https://www.readbyqxmd.com/read/28631923/influence-of-ingesting-a-flavonoid-rich-supplement-on-the-metabolome-and-concentration-of-urine-phenolics-in-overweight-obese-women
#14
David C Nieman, Sivapriya Ramamoorthy, Colin D Kay, Courtney L Goodman, Christopher R Capps, Zach L Shue, Nicole Heyl, Mary H Grace
This study evaluated the effect of ingesting a flavonoid-rich supplement (329 mg/d) on total urine phenolics and shifts in plasma metabolites in overweight/obese female adults using untargeted metabolomics procedures. Participants (N=103, 18-65 y, BMI ≥ 25 kg/m2) were randomized to flavonoid (F) or placebo (P) groups for 12 weeks, with blood and 24-h urine samples collected pre-study, 4- and 12-weeks in a parallel design. Supplements were prepared as chewable tablets, and included vitamin C, wild bilberry fruit extract, green tea leaf extract, quercetin, caffeine, and omega 3 fatty acids...
June 20, 2017: Journal of Proteome Research
https://www.readbyqxmd.com/read/28631897/the-interaction-mode-of-groove-binding-between-quercetin-and-calf-thymus-dna-based-on-spectrometry-and-simulation
#15
Yijie Sha, Xu Chen, Bing Niu, Qin Chen
Quercetin, a ubiquitous flavanoid, has numerous pharmacological effects, such as antioxidant and antitumor. Previous studies showed nucleic acids were the potential biological targets for antitumor medicine. For exploring the mechanism of DNA-target medicine, the interaction between quercetin and calf thymus DNA was studied based on the method of spectrometry and simulation in our study. Firstly, the interaction between quercetin and calf thymus DNA was confirmed by fluorescence spectrometry. Furthermore, circular dichroism, fluorescence polarization, competitive displacement assay and salt concentration dependence assay were applied to search the interaction mode of quercetin-calf thymus DNA, which proved the existence of groove binding and electrostatic interaction...
June 20, 2017: Chemistry & Biodiversity
https://www.readbyqxmd.com/read/28631409/exploration-of-a-ternary-deep-eutectic-solvent-of-methyltriphenylphosphonium-bromide-chalcone-formic-acid-for-the-selective-recognition-of-rutin-and-quercetin-in-herba-artemisiae-scopariae
#16
Wanwan Ma, Tangand Baokun, Kyung Ho Row
A methyltriphenylphosphonium bromide/chalcone/formic acid as a green ternary deep eutectic solvent was applied as a functional monomer and dummy template simultaneously in the synthesis of a new molecularly imprinted polymer. Ternary deep eutectic solvent based molecularly imprinted polymers were used as a solid-phase extraction sorbent in the separation and purification of rutin and quercetin from Herba Artemisiae Scopariae combined with high-performance liquid chromatography. FTIR spectroscopy and field-emission scanning electron microscopy were applied to characterize the deep eutectic solvent based molecularly imprinted polymers synthesized using different molar ratios of chalcone...
June 20, 2017: Journal of Separation Science
https://www.readbyqxmd.com/read/28629861/flavonoids-determine-the-rate-of-fibrillogenesis-and-structure-of-collagen-type-i-fibrils-in-vitro
#17
Yuri A Kim, Yury S Tarahovsky, Sergei G Gaidin, Elena A Yagolnik, Eugeny N Muzafarov
Collagen fibrils are produced from collagen monomers not only in vivo, but also in vitro. The ability to have an influence on the structure and properties of fibrils may find medical application and can be useful for controlling the formation of collagen gels and sheets in tissue engineering. Here we investigated the influence of flavonoids, distinguished by the number of hydroxyl groups in the B-ring, on the formation of collagen fibrils. A correlation was found between the number of hydroxyl groups, lipophilicity of molecules and their ability to influence the fibril formation...
June 16, 2017: International Journal of Biological Macromolecules
https://www.readbyqxmd.com/read/28629287/anti-acetylcholinesterase-activity-and-antioxidant-properties-of-extracts-and-fractions-of-carpolobia-lutea
#18
Lucky Legbosi Nwidu, Ekramy Elmorsy, Jack Thornton, Buddhika Wijamunige, Anusha Wijesekara, Rebecca Tarbox, Averil Warren, Wayne Grant Carter
CONTEXT: There is an unmet need to discover new treatments for Alzheimer's disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae). OBJECTIVE: The objective of this study is to quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities and cell cytotoxicity. MATERIALS AND METHODS: Plant stem, leaves and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0...
December 2017: Pharmaceutical Biology
https://www.readbyqxmd.com/read/28629212/a-study-of-the-modulating-action-of-quercetin-on-biochemical-and-histological-alterations-induced-by-lead-exposure-in-the-liver-and-kidney-of-rats
#19
Azza Sedky, Hany Elsawy
Lead is a highly toxic metal and a very potent poison. Lead poisoning is a serious condition but can be treated. Quercetin is a flavonoid with many beneficial uses. The aim of the present study was to investigate the possible modulating action of quercetin as a model of an antioxidant against the toxic effects of lead acetate on liver and kidneys of rats. Rats were randomly divided into four groups: (i) saline group (control); (ii) lead group received i.p. lead acetate (20 mg/kg b.w.); (iii) quercetin group received i...
June 30, 2017: Chinese Journal of Physiology
https://www.readbyqxmd.com/read/28628137/-antagonistic-effect-of-quercetin-on-pm2-5-toxicity-in-the-rat-s-embryonic-development-in-vitro
#20
A Q Fan, J Q Feng, W Liu, M J Zhang, T Liu, Y L Zhou, Y J Xu
OBJECTIVE: To explore the antagonistic effect of quercetin on fine particulate matter (PM2.5)-induced embryonic developmental toxicity in vitro. METHODS: PM2.5 was collected on glass fiber filters by PM2.5 samplers during the heating period of Dec. 2015 to Mar. 2016 in an area of Haidian District, Beijing City. The sampled filters were cut into 1 cm×3 cm pieces followed by sonication. The PM2.5 suspension was filtered into a 10 cm glass dish through 8 layers of sterile carbasus and stored at -80 °C until freeze drying...
June 18, 2017: Beijing da Xue Xue Bao. Yi Xue Ban, Journal of Peking University. Health Sciences
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