Isolation, Structures, and Biological Activities of Triterpenoids from a <i>Penares</i> sp. Marine Sponge
2013-09-27T00:00:00Z (GMT) by
Six new triterpenoids (<b>1</b>–<b>6</b>) and the previously known penasterone, acetylpenasterol, and ergosta-4,24(28)-dien-3-one were isolated from a <i>Penares</i> sp. sponge collected from Vietnamese waters. Structures of the obtained compounds were established by extensive 1D and 2D NMR spectroscopy and mass spectrometry. Configurations of the triterpene epoxy lactones (<b>1</b>–<b>4</b>) were determined on the basis of NOESY and CD data and calculation of spin coupling constants and confirmed by X-ray crystallographic analysis of compound <b>2</b>. The isolated triterpenoid <b>6</b> was cytotoxic against human leukemia HL-60 cells (IC<sub>50</sub> = 9.7 μM).
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