Altercrasin A, a novel decalin derivative with spirotetramic acid, produced by a sea urchin-derived Alternaria sp.

Altercrasin A (1), a novel decalin derivative with a spiroskeleton, has been isolated from a strain of Alternaria sp. OUPS-117D-1 originally derived from the sea urchin Anthocidaris crassispina, and its structure has been elucidated on the basis of spectroscopic analyses using 1D and 2D NMR techniques. In addition, the absolute configuration for 1 was established by chemical transformation and the modified Mosher's method. This compound exhibited moderate cytotoxicity against human cancer cell lines. (C) 2015 Elsevier Ltd. All rights reserved.