Phytochemical investigations of Calotropis procera leaves have led to the isolation of two new compounds: quercetagetin-6-methyl ether 3-O-beta-D-4C1-galacturonopyranoside (3) and (E)-3-(4-methoxyphenyl-2-O-beta-D-4C1 -glucopyranoside)-methyl propenoate (4), along with eleven known metabolites: nine flavonol and two cinnamic acid derivatives. All metabolites were isolated for the first time fro...

BACKGROUND Natural food products have been used for combating human diseases for thousands of years. Naturally occurring flavonoids including flavones, flavonols, flavanones, flavonols, isoflavones and anthocyanidins have been proposed as effective supplements for management and prevention of diabetes and its long-term complications based on in vitro and animal models. AIM To summarize the ro...

Clusia fluminensis Planch. & Triana (Clusiaceae Lindl.) is a native species found in regions of high luminosity and water restriction. The aim of this study was to evaluate the antioxidant activity of Clusia fluminensis crude extracts through the scavenging of the stable free radical DPPH, and the determination of flavones and flavonols content in these extracts. The fruit acetonic extract show...

The content of biologically active substances and antioxidant activity in leaves inflorescences three species from the tribe Cynareae Asteraceae family: Centaurea cyanus,Centaurea macrocephala, Rhaponticum carthamoides, grown under conditions Central Siberian Botanical Garden introduction was studied. It determined that contain flavonols, catechins, tannins, carotenoids, pectin substances. high...

Because direct oxidation of flavonols by polyphenol oxidase (PPO) has not previously been reported and, given the importance of flavonols, the ability of broad bean seed PPO to oxidize the flavonol quercetin was studied. The reaction was followed by recording spectral changes with time. Maximal spectral changes were observed at 291 nm (increase) and at 372 nm (decrease). The presence of two iso...

Externally added quercetin (100 micromolar) was oxidized by intact spinach chloroplasts at a rate of 30 micromoles per mg chlorophyll per hour in the presence of 100 micromolar H(2)O(2). The oxidation rate was increased by about 20% in a hypotonic reaction mixture. The thylakoid fraction also oxidized the flavonol in the presence of H(2)O(2), and the rate was about 25% of that by intact chlorop...

Dietary-derived agents, such as the flavonoids, are of particular interest for prostate cancer (PCa) chemoprevention as they may offer a favourable safety and side-effect profile. An agent that demonstrates action on the androgen receptor (AR) axis may have value for preventing or treating castrate-resistant PCa. Four main flavonols - quercetin, myricetin, kaempferol, and fisetin - have been de...

Lotus corniculatus, Leguminosae, O-Methyltransferase, Flavonols, 8-O-Methylation, 3'-0-Methylation Two O-methyltransferases specific for flavonol rings A and B were isolated from young flower buds of Lotus corniculatus. They were partially purified by ammonium sulphate precipitation and successive chromatography on Sephadex G-100 and Polybuffer ion exchanger. One enzyme focused at pi 5.5 and ca...

Black peanut skins as a byproduct from peanut industry contain abundant anthocyanins, evaluated as 8.61±0.27mg/g dry black peanut skins, are currently poorly exploited. In this work, four anthocyanins and three major flavonols were detected and identified by HPLC-PDA-ESI-MS/MS from the acidified water extract of black peanut skins of Arachis hypogaea L. After preliminary removal of flavonols by...

The amounts of three flavonoids, quercetin, kaempferol, and myricetin, in tomatoes (Solanum lycopersicum L.) and tomato-based products produced in Turkey has been determined by reversed phase high-performance liquid chromatography (RPHPLC) with UV detection. The HPLC profiles of five types of tomato, one commercial composite tomato juice, and three types of tomato paste, were obtained after aci...