Bioactive constituents from <i>Dioscorea bulbifera</i> L. rhizomes with antioxidant and α-glucosidase inhibitory properties

As a result, nineteen known compounds were isolated and structurally characterised, comprising emodin (<b>1</b>), piceid (<b>2</b>), quercetin (<b>3</b>), physcion (<b>4</b>), kaempferol (<b>5</b>), caffeic acid methyl ester (<b>6</b>), resveratrol (<b>7</b>), 3,4,5-trihydroxybenzoic acid (<b>8</b>), resveratrol-2’’-<i>O</i>-galloylester (<b>9</b>), bisdemethoxycurcumin (<b>10</b>), resveratrol-<i>O</i>-<i>E</i>-phyllanthine (<b>11</b>), rhein (<b>12</b>), aloe-emodin (<b>13</b>), 5-methoxy-7-hydroxy-1(3H)-benzofuranone (<b>14</b>), questinol (<b>15</b>), vanillic acid (<b>16</b>), <i>β</i>-sitosterol (<b>17</b>), 3,4-dihydroxybenzoic acid (<b>18</b>), and diosgenin (<b>19</b>).

All isolated compounds were evaluated for their α-glucosidase inhibitory and antioxidant activity. The results demonstrated that compounds <b>3</b>, <b>5</b>, <b>8</b>, <b>9</b>, and <b>18</b> exhibited antioxidant activity, with radical scavenging rates ranging from 84.19% to 97.73%, while <b>9</b>, <b>11</b>, <b>13</b>, and <b>15</b> showed α-glucosidase inhibitory effects, with IC₅₀ values ranging from 0.4556 to 1.3528 mg/mL.