Formamido-Diterpenes from the South China Sea Sponge <em>Acanthella cavernosa</em>

Abstract

Seven new formamido-diterpenes, cavernenes A–D (<strong>1</strong>–<strong>4</strong>), kalihinenes E and F (<strong>5</strong>–<strong>6</strong>), and kalihipyran C (<strong>7</strong>), together with five known compounds (<strong>8</strong>–<strong>12</strong>), were isolated from the South China Sea sponge <em>Acanthella cavernosa</em>. Structures were established using IR, HRESIMS, 1D and 2D NMR, and single X-ray diffraction techniques. The isolated compounds were assessed for their cytotoxicity against a small panel of human cancer cell lines (HCT-116, A549, HeLa, QGY-7701, and MDA-MB-231) with IC₅₀ values in the range of 6–18 μM. In addition, compound <strong>9</strong> showed weak antifungal activity against <em>Trichophyton rubrum</em> and <em>Microsporum gypseum</em> with MIC values of 8 and 32 μg/mL, respectively, compound <strong>10</strong> displayed weak antifungal activity against fungi <em>Candida albicans</em>, <em>C</em><em>ryptococcus neoformans</em>, <em>T. rubrum</em>, and<em> M. gypseum </em>with MIC values of 8, 8, 4, and 8 μg/mL, respectively.

Keywords

• &lt;em&gt;Acanthella cavernosa&lt;/em&gt;
• formamido-diterpenes
• cytotoxicity
• antifungal activity