benzofurans and fustin

Topics: Animals; Antioxidants; Apoptosis; Benzofurans; Caspase 3; Cell Survival; Chalcones; Ditiocarb; Flavonoids; Hydrogen Peroxide; Neurons; Oxidative Stress; PC12 Cells; Phenols; Plant Extracts; Rats; Rhus; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Superoxide Dismutase

Ethyl acetate fraction (EAF) from Rhus verniciflua Stokes is an important source of bioactive compounds. The aim of this study was the tentative identification and quantification of phenolic compounds, comparison of the phenolic structure-antioxidant activity relationships. Twelve compounds of EAF belonging to polyphenol types were detected by high performance liquid chromatography and analysed on line with negative ion electrospray ionisation tandem mass spectrometry, which were ethoxy 3-hydroxy benzoic acid, gallic acid (GA), 3,4-dihydroxy amygdalic acid, gallic acid cetyl ester, protocatechuic acid (PA), fustin, ethyl gallate (EG), garbanzol, fisetin, sulfuretin, butin and 3,7-dihydroxyflavanone-4'-rhamnoside. The antioxidant activity were evaluated based on the different types of radical scavenging capacities, i.e. DPPH·, ABTS·+ and OH. The antioxidant capacity of EAF mainly depended on the GA, EG, PA, fisetin, sulfuretin and butin. The phenolics exhibited a dose-dependent behaviour and high antioxidant ability.

Topics: Acetates; Antioxidants; Benzofurans; Benzopyrans; Chromatography, High Pressure Liquid; Flavonoids; Flavonols; Free Radical Scavengers; Phenols; Plant Extracts; Rhus; Spectrometry, Mass, Electrospray Ionization

A novel unusual trimmer chalcone, polyanthumin (1), together with five known compounds myricetin 3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (2), sulfuretin (3), fustin (4), gallic acid (5), and ethyl gallate (6), was isolated from the dry stems of Memecylon polyanthum H.L. Li. Among them, compound 1 is a new chalcone trimmer with a novel cyclobutane skeleton in nature. Compounds 3 and 4 are flavonoids carrying a single 7-OH in A ring, which provided the first example of these class flavonoids from the family Melastomataceae. In addition, the antitumor activities for 2-4 were reported for the first time in this study. The antitumor effects of the isolated compounds 1-6 in vitro were assayed by the SRB method using human cancer K562 cells, with the inhibition rates ranging from 39.4% to 54.5% at 100 μg/ml. The IC50 values of compounds 1 and 3 for the inhibition of K562 cell proliferation were determined to be 45.4 and 30.5 μg/ml, respectively. To the best of our knowledge, compound 1 was the second sample as chalcone trimer. In addition, the antitumor activities for 2-4 were reported for the first time in this study.

Topics: Antineoplastic Agents; Benzofurans; Chalcone; Chalcones; Cyclobutanes; Drug Screening Assays, Antitumor; Drugs, Chinese Herbal; Electron Spin Resonance Spectroscopy; Flavonoids; Gallic Acid; Humans; K562 Cells; Melastomataceae; Molecular Structure; Plant Stems; Stereoisomerism