BACKGROUND Extraction prior to component analysis is the primary step in the recovery and isolation of bioactive phytochemicals from plant materials. METHODS Response surface methodology was applied to optimize ultrasound-assisted extraction conditions followed by ultra high performance liquid chromatography (UHPLC) to achieve high catechin, myricetin, and quercetin contents, and high antioxi...

Previous studies showed that hybrid grapes often have qualitatively and quantitatively higher polyphenolic contents than the common V. vinifera grape varieties. In general, these compounds are studied for grape chemotaxonomy and for nutraceutical purposes due to their relevant antioxidant activity. Non-anthocyanic flavonoid composition of five red hybrid grape varieties produced by crossing of ...

In the present study the effects of three flavonoids on the repair of H2O2-induced DNA strand breaks were investigated in Caco-2, Hep G2, and V79 cells. At the concentrations used, myricetin, quercetin, rutin, and H2O2 did not significantly affect cell viability in all the cell lines. Catalase activity was measured in V79 cells and was found to be considerably lower than activities previously m...

A new flavonol galactopyranoside, myricetin 3-O-(2'',3''-digalloyl)-β-D-galactopyranoide (1), and 23 known constituents, including myricetin 3-O-(2''-galloyl)-β-D-galactopyranoide (2), myricitrin (3), myricetin (4), quercetin 3-O-(2'', 3''-digalloyl)-β-D-galactopyranoide (5), quercetin 3-O-(2''-galloyl)-β-D-galactopyranoide (6), hyperin (7), isoquercetrin (8), quercetin (9), kaempferol (10), ap...

The specific phosphoinositide 3-kinase (PI3K) inhibitors wortmannin and LY294002 have been invaluable tools for elucidating the roles of these enzymes in signal transduction pathways. The X-ray crystallographic structures of PI3Kgamma bound to these lipid kinase inhibitors and to the broad-spectrum protein kinase inhibitors quercetin, myricetin, and staurosporine reveal how these compounds fit ...

From the MeOH extract of the leaves of Eugenia uniflora eight compounds were isolated, including one sterol, β-sitosterol (1); two triterpenes, betulinic acid (2) and centelloside C (8); three flavonoids, myricetrin (3), myricetin 3-O-(4’’-O-galloyl)-αL-rhamnopyranoside (4), and myricetin 3-O-β-D-glucopyranoside (5); and two megastigmanes, actinidioionoside (6), and (6S,9R)-roseoside (7). All t...

Flavonoids, a group of compounds found primarily in vegetables and fruits, are generally believed to be beneficial to biological systems. Isolated guinea pig enterocytes were exposed to three of these compounds (kaempferol, quercetin, and myricetin) in concentrations of 50-450 microM. Toxicity was examined using trypan blue exclusion and lactic dehydrogenase (LDH) leakage. All three flavonoids ...

In this paper, the extraction of polyphenols from amaranth seed using a Box–Benhken design four factors—ultra-turrax speed, solid-to-liquid ratio (RSL), methanol concentration and time—were studied. There were two responses studied for model: total phenolic content (TPC) flavonoid (TFC). The factors which influenced most TPC TFC RSL, ultra-turrax speed. Twelve acids (rosmarinic acid, p-coumaric...

A purification and fractionation process of the edible flowers Tibouchina mollis urvilleana followed by first attempt to anthocyanin flavonol characterisation identification UHPLC-DAD-ESI-MS were developed. T. exhibited a higher monomeric content, mainly due presence 3-O-(6′-p-coumaroyl)-glucoside derivatives malvidin petunidin. Quercetin-3-O-hexoside was major identified in urvilleana, lack my...