Conicamin, a novel histamine antagonist from the mediterranean tunicate Aplidium conicum

In addition to the known 6-bromo-hypaphorine (2) and plakohypaphorine-A (3), the methanol extract of the Mediterranean tunicate Aplidium conicum was shown to contain conicamin, a novel indole alkaloid having histamine-antagonistic activity which structure was determined to be 1 on the basis of the spectral data.