Didemnidines A and B, Indole Spermidine Alkaloids from the New Zealand Ascidian Didemnum sp.

This is the authors' abstract. We don't add key points for this paper.

Two new indole spermidine alkaloids, didemnidines A (1) and B (2), have been isolated from the New Zealand ascidian Didemnum sp. The structures of the metabolites, determined by analysis of 2D NMR spectra and confirmed via synthesis, embody an indole-3-glyoxylamide moiety linked to the N(1) position of spermidine, the latter motif being particularly rare among marine natural products. Didemnidine B and a synthetic precursor exhibited mild in vitro growth inhibition of Plasmodium falciparum with IC(50)'s of 15 and 8.4 μM, respectively.