Isolaurenidificin and Bromlaurenidificin, Two New C15-Acetogenins from the Red Alga Laurencia obtusa

Abstract

Chromatographic fractionation of the CH₂Cl₂/MeOH extract of the Red Sea red alga <i>Laurencia obtusa</i> gave two new hexahydrofuro[3,2-<i>b</i>]furan-based C₁₅-acetogenins, namely, isolaurenidificin (<b>1</b>) and bromlaurenidificin (<b>2</b>). The chemical structures were elucidated based on extensive analyses of their spectral data. Compounds <b>1</b> and <b>2</b> showed no toxicity (<i>LC</i>₅₀ > 12 mM) using <i>Artemia salina</i> as test organism. Both compounds showed weak cytotoxicity against A549, HepG-2, HCT116, MCF-7, and PC-3 cells, however, they exhibited a relatively potent cytotoxic activity against peripheral blood neutrophils. This can be attributed partly to induction of apoptosis.