Coproverdine, a novel, cytotoxic marine alkaloid from a New Zealand ascidian

The crude extract of a New Zealand ascidian displayed antitumor activity. Bioassay-directed fractionation yielded a novel alkaloid, coproverdine (1). The structure of 1 was assigned on the basis of detailed spectroscopic analysis. Coproverdine (1) was responsible for the antitumor activity of the crude extract.