Antioxidant phenolic compounds from the rhizomes of <i>Astilbe rivularis</i>

<p>The rhizomes of <i>Astilbe rivularis</i>, 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 (<b>1</b>), 11-<i>O</i>-galloylbergenin (<b>2</b>), (+)-catechin (<b>3</b>), (−)-catechin (<b>4</b>), (−)-afzelechin (<b>5</b>), (−)-epiafzelechin (<b>6</b>) and 2-(<i>β</i>-D-glucopyranosyloxy)-4-hydroxylbenzenacetonitrile (<b>7</b>) 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 <i>in vitro</i> antioxidant activity by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. 11-<i>O</i>-Galloylbergenin (<b>2</b>), (+)-catechin (<b>3</b>), (−)-catechin (<b>4</b>), (−)-afzelechin (<b>5</b>) and (−)-epiafzelechin (<b>6</b>) showed potent antioxidant activity.</p>