Cytotoxic constituents of <i>Lasiosphaera fenzlii</i> on different cell lines and the synergistic effects with paclitaxel

<p>The fruit body of <i>Lasiosphaera fenzlii</i> was found to show cytotoxicity on cancer cells during a preliminary screening. Repeated column chromatography of the fungal methanol extract resulted in the isolation of six compounds identified as 5<i>α</i>,8<i>α</i>-epidioxy-ergosta-6,22-dien-3<i>β</i>-ol (<b>1</b>), 5<i>α</i>,8<i>α</i>-epidioxy-ergosta-6,9(11),22-trien-3<i>β</i>-ol (<b>2</b>), 5<i>α</i>-ergosta-7,22-dien-3<i>β</i>-ol (<b>3</b>), 5<i>α</i>-ergosta-7,22-dien-3-one (<b>4</b>), ergosta-7,22-dien-3<i>β</i>,5<i>α</i>,6<i>β</i>-triol (<b>5</b>) and 6-dihydroxy-2,3-dihydro-1H-isoindol-1-one (<b>6</b>). The two peroxide compounds, <b>1</b> and <b>2</b>, showed cytotoxic activity and compound <b>1</b> was selectively cytotoxic to cancer cells. Furthermore, compound <b>1</b> synergised the cytotoxicity of paclitaxel on Hela cells by increasing intracellular accumulation of paclitaxel in cancer cells but not in normal cells.</p