Makaluvic Acids from the South African Latrunculid Sponge <i>Strongylodesma </i><i>a</i><i>liwaliensis</i>

Abstract

Two new metabolites, makaluvic acid C (1) and N-1-beta-d-ribofuranosylmakaluvic acid C (2), were isolated from the recently described sponge Strongylodesma aliwaliensis collected off the east coast of South Africa. Standard spectroscopic techniques provided the structures of both compounds. Chiral GC analysis of the peracetylated aldononitrile derivative of the acid hydrolysate of 2 confirmed the d-configuration of the ribose moiety in this compound. Compound 2 and four related pyrroloquinoline metabolites, isolated previously from S. aliwaliensis, exhibited in vitro cytotoxicity against esophageal cancer cells.