epiafzelechin and 1-1-diphenyl-2-picrylhydrazyl

The rhizomes of Astilbe rivularis, commonly known as 'Thulo Okhati' are widely used in Nepal as tonic for uterine and menstrual disorders. In our preliminary study, the 70% MeOH extract of the rhizomes showed potent antioxidant activity. Hence, present study was aimed for the isolation of potent antioxidant constituents. Bergenin (1), 11-O-galloylbergenin (2), (+)-catechin (3), (-)-catechin (4), (-)-afzelechin (5), (-)-epiafzelechin (6) and 2-(β-D-glucopyranosyloxy)-4-hydroxylbenzenacetonitrile (7) were isolated from the rhizomes. Structures of these compounds were elucidated on the basis of spectroscopic methods. All these isolated compounds were evaluated for their in vitro antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. 11-O-Galloylbergenin (2), (+)-catechin (3), (-)-catechin (4), (-)-afzelechin (5) and (-)-epiafzelechin (6) showed potent antioxidant activity.

Topics: Antioxidants; Benzopyrans; Biphenyl Compounds; Catechin; Drug Evaluation, Preclinical; Flavonoids; Gallic Acid; Magnetic Resonance Spectroscopy; Molecular Structure; Nepal; Phenols; Picrates; Plant Extracts; Rhizome; Saxifragaceae

A new flavan-3-ol glycoside, (-)-epicatechin-5-O-beta-D-glucosyl-3-benzoate (1), and two known compounds, (-)-epicatechin and (-)-epiafzelechin, were isolated from an EtOAc extract of Celastrus orbiculatus aerial parts that exhibited significant antioxidant effect in a 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical assay. The structure of 1 was elucidated by spectroscopic analyses, and compound 1 and its aglycon, (-)-epicatechin-3-benzoate (2), were found to be moderately active as antioxidants in the DPPH assay.

Topics: Antioxidants; Bepridil; Biphenyl Compounds; Catechin; Flavonoids; Free Radical Scavengers; Free Radicals; Hydrolysis; Picrates; Plants, Medicinal