Absolute Configuration of Labdane Diterpenoids from <i>Physalis nicandroides</i>

A mixture of the new epimeric labdenetriols <b>1</b> and <b>2</b> was isolated from the aerial parts of <i>Physalis nicandroides</i>. The structures of <b>1</b> and <b>2</b>, including their absolute configurations, were established by analyses of their spectroscopic data, together with the X-ray diffraction analysis of acetonide <b>3</b> and chemical correlation with (−)-(13<i>E</i>)-labd-13-ene-8α,15-diol (<b>6</b>), whose absolute configuration was also confirmed by X-ray analysis of its dibromo derivative <b>7</b>. The epimeric labdenediols <b>8</b> and <b>9</b>, the known labdanes <b>6</b> and <b>11</b>, and the acylsucroses <b>12</b> and <b>13</b> were also isolated. Labdanes <b>6</b> and <b>11</b> showed moderate anti-inflammatory activities in the induced ear edema model