8-isopentenyl isoflavone derivatives from the whole herb of <i>Sphaerophysa salsula</i>

<p>Phytochemical studies on the whole herb of <i>Sphaerophysa salsula</i> has resulted in the discovery of one new 8-isopentenyl isoflavone derivative, named sphaerosin s<sub>2</sub> (3-(8-(2-hydroxypropan-2-yl)-3,4-dihydro-2<i>H</i>-furo[2,3-<i>h</i>]chromen-3-yl)-2,6-dimethoxyphenol) (<b>1</b>), along with four know 8-isopentenyl isoflavone derivatives (<b>2</b>–<b>5</b>). Compounds (<b>2</b>, <b>4</b> and <b>5</b>) were isolated for the first time from this species. Their structures were elucidated on the basis of ESI-MS, UV, IR, 1D NMR and 2D NMR data.</p>