Purpose: To investigate 38 natural and 62 branded lemon juices for their total antioxidant activities and flavonoid content. Methods: The ferric reducing antioxidant power was applied to evaluation of antioxidant. Additionally quercetin, eriocitrin, diosmin and hesperidin contents were evaluated by high performance liquid chromatography (HPLC). Results: Total antioxidant activity of the juices ...

Phytochemical investigations of ethyl acetate-soluble part of the aerial part of Hypericum scabrum L. delivered eight pure phenolic compounds 1-8. The pure compounds were identified through physico-chemical, NMR (1D, 2D) and mass spectrometric studies as: 3-8''-bisapigenin (1), quercetin (2), quercetin-3-O-α-l-arabinofuranoside (3), quercetin-3-O-α-l-rhamnoside (4), quercetin-3-O-β-d-glucopyran...

The principal active constituents of Polygonum capitatum are phenolic acids and flavonoids, such as gallic acid, quercitrin, and quercetin. The aim of this study was to develop and validate a method to determine the three constituents and the corresponding conjugated metabolites of Polygonum capitatum in vivo and to conduct pharmacokinetic studies on the herb, a well-known Miao medicinal plant ...

The aim of the present study was to investigate the effects of SA on UV-A, UV-B, and UV-C stressed plants. Data showed that SA counteracted the UV harmful effects on pepper. Pepper (Capsicum annuum L.) seedlings sprayed with salicylic acid (SA) and treated with UV-A (320-390 nm), UV-B (312 nm), and UV-C (254 nm) of 6.1, 5.8, and 5.7 W m-2, respectively. UV significantly increased contents of as...

The flavonoid quercetin suppresses cell proliferation and enhances apoptosis in vitro. In this study, we determined whether quercetin protects against colon cancer by regulating the protein level of phosphatidylinositol 3-kinase (PI 3-kinase) and Akt or by suppressing the expression of proinflammatory mediators [cyclooxygenase (COX)-1, COX-2, inducible nitric oxide synthase (iNOS)] during the a...

Oxidative stress is one of the major factors in the pathogenesis of liver disease. Quercetin is a plant-based antioxidant traditionally used as a treatment for hepatic injury, but its poor solubility affects its bioavailability. We here report the regulative effects on hepatoprotection and absorption in mice of quercetin sulfation to form quercetin-5',8-disulfonate (QS), a novel synthetic compo...

UDP-glucuronosyltransferase (UGT) activity toward the flavonoid quercetin and UGT protein were characterized in three equidistant small intestine (SI) segments from 4-, 12-, 18-, and 28-month-old male Fischer 344 rats (n = 8/age) using villin to control for enterocyte content. SI microsomal intrinsic clearance of quercetin was increased 3- to 9-fold from 4 months in the proximal and distal SI a...

The purpose of this study was to examine the effect of a 40% high-fat diet (HFD) supplemented with a dietary attainable level of quercetin (0.02%) on body composition, adipose tissue (AT) inflammation, Non-Alcoholic Fatty-Liver Disease (NAFLD), and metabolic outcomes. Diets were administered for 16 weeks to C57BL/6J mice (n = 10/group) beginning at 4 weeks of age. Body composition and fasting b...

Major brands of cocoa powder products present in the Spanish market were analyzed for monomeric flavanols [(+)-catechin and (-)-epicatechin] and flavonols [quercetin-3-glucuronide, quercetin-3-glucoside (isoquercitrin), quercetin-3-arabinoside, and quercetin]. In addition, the influence of the manufacturing process of cocoa powder products, in particular, the alkalinization treatment ( Dutching...

Quercetin supplementation increases muscle oxidative capacity and endurance in mice, but its ergogenic effect in humans has not been established. Our study investigates the effects of short-duration chronic quercetin supplementation on muscle oxidative capacity; metabolic, perceptual, and neuromuscular determinants of performance in prolonged exercise; and cycling performance in untrained men. ...