Two new acyclic bis-guanidine alkaloids, unguiculins B-C (2-3), were isolated from a French Polynesian sponge Monanchora n. sp. together with the known compound unguiculin A (1). Their structures were established by spectroscopic data interpretation and comparison with the literature. Unguiculins A-C displayed antiproliferative and cytotoxic efficacy against several human cancer cells with IC50 values in the micromolar range.
Keywords: Crambeidae; Monanchora; guanidine; spermidine alkaloid; unguiculin.