A new dihydrobenzofuran lignan and potential <i>α</i>-glucosidase inhibitory activity of isolated compounds from <i>Mitrephora teysmannii</i>

Abstract

<p>A new dihydrobenzofuran lignan, (2<i>R</i>,3<i>S</i>)-2-(3′,4′-dimethoxyphenyl)-5-(3-hydroxypropyl)-7-methoxy-2,3-dihydrobenzofuran-3-methyl acetate, named as mitredrusin (<b>1</b>), was isolated from the leaves of <i>Mitrephora teysmannii</i> (Annonaceae) together with 12 known compounds including a related dihydrobenzofuran lignan: (−)-3′,4-di-<i>O</i>-methylcedrusin (<b>2</b>), four polyacetylenic acids: 13(<i>E</i>)-octadecene-9,11-diynoic acid (<b>3</b>), 13(<i>E</i>),17-octadecadiene-9,11-diynoic acid (<b>4</b>), octadeca-9,11,13-triynoic acid (<b>5</b>) and octadeca-17-en-9,11,13-triynoic acid (<b>6</b>), five lignans: (−)-eudesmin (<b>7</b>), (−)-epieudesmin (<b>8</b>), (−)-phillygenin (<b>9</b>), magnone A (<b>10</b>) and forsythialan B (<b>11</b>) and two megastigmans: (3<i>S</i>,5<i>R</i>,6<i>S</i>,7<i>E</i>,9<i>R</i>)-7-megastigmene-3,6,9-triol (<b>12</b>) and annoionol A (<b>13</b>). The chemical structures of these compounds were established on the basis of their 1-D and 2-D NMR spectroscopic data. All compounds were evaluated for their <i>α</i>-glucosidase inhibitory activity. Among these isolates, polyacetylenic acids <b>3</b> and <b>4</b> showed more than 20-fold much higher activity compared with that of the antidiabetic drug acarbose.</p