| Summary: | Two undescribed rearranged cadinane-type sesquiterpenoids (<b>1</b>–<b>2</b>), named sinulaketol A-B, together with one new chlorinated steroid (<b>3</b>), one new gorgosterol (<b>4</b>), one known sesquiterpene (<b>5</b>), one known dibromoditerpene (<b>6</b>) and two known polyhydroxylated steroids (<b>7</b>–<b>8</b>) were isolated from the soft coral <i>Sinularia brassica</i>. The structures of these compounds were established by extensive spectroscopic analysis, including HRESIMS, 1D, and 2D NMR spectroscopy. Their absolute configurations were also determined by the ECD calculations and DP4+ probability analysis. Antileishmanial activity of compounds <b>1</b>–<b>8</b> was evaluated in vitro against the amastigote forms of <i>Leishmania donovani</i>, in which compounds <b>3</b>, <b>6</b>, and <b>7</b> inhibited the growth of <i>L. donovani</i> by 58.7, 74.3, 54.7%, respectively, at a concentration of 50 μM. Antimicrobial effect of the isolated compounds were also evaluated against <i>Candida albicans</i>, <i>Staphylococcus aureus</i>, and <i>Escherichia coli.</i> Compound <b>6</b>, a brominated diterpene, exhibited antimicrobial effect against <i>S</i>. <i>aureus</i>.
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