Phenolic compounds from the flowers of Nepalese medicinal plant <i>Aconogonon molle</i> and their DPPH free radical-scavenging activities

<div><p>Eleven phenolic compounds, quercetin (<b>1</b>), quercetin 3-<i>O</i>-β-d-galactopyranoside (<b>2</b>), quercetin 3-<i>O</i>-(6″-<i>O</i>-galloyl)-β-d-galactopyranoside (<b>3</b>), quercetin 3-<i>O</i>-(6″-<i>O</i>-caffeoyl)-β-d-galactopyranoside (<b>4</b>), quercetin 3-<i>O</i>-β-d-glucopyranoside (<b>5</b>), rutin (<b>6</b>) quercetin 3-<i>O</i>-α-l-arabinopyranoside (<b>7</b>), quercetin 3-<i>O</i>-α-l-arabinofuranoside (<b>8</b>), protocatechulic acid (<b>9</b>), gallic acid (<b>10</b>) and chlorogenic acid (<b>11</b>), were isolated from the flowers of <i>Aconogonon molle</i>, a Nepalese medicinal plant. Structures of these compounds were elucidated on the basis of spectroscopic methods. All these compounds were isolated for the first time from flowers, and five compounds (<b>4</b>, <b>5</b>, <b>8</b>, <b>9</b> and <b>11</b>) were isolated for the first time from <i>A. molle.</i> All of these isolated compounds were evaluated for their <i>in vitro</i> antioxidant activity by using the 1,1-diphenyl-2-picrylhydrazyl radical-scavenging method. Quercetin (<b>1</b>), quercetin glycosides (<b>2</b>–<b>8</b>) and gallic acid (<b>10</b>) exhibited potent antioxidant activity.</p></div>