Cristaxenicin A, an antiprotozoal xenicane diterpenoid from the deep sea gorgonian Acanthoprimnoa cristata.

A new xenicane diterpenoid, cristaxenicin A (1), has been isolated from the deep sea gorgonian Acanthoprimnoa cristata. The structure of 1 was elucidated on the basis of spectral analysis including NMR and MS. The absolute configuration of 1 was determined on the basis of quantum chemical calculation of CD spectra. Cristaxenicin A (1) showed antiprotozoal activities against Leishmania amazonensis and Trypanosoma congolense with IC(50) values of 0.088 and 0.25 µM, respectively.