Tanzawaic Acids from a Deep-Sea Derived Penicillium Species.

Twelve new tanzawaic acid derivatives, penitanzacids A-F ( 1-6 ), and G-J ( 9-12 ), and hatsusamides C-D ( 13-14 ), together with two revised structures [tanzawaic acids I-J ( 7-8 )] and three known compounds ( 15-17 ) were isolated from the deep-sea-derived fungus Penicillium sp. KWF32. Their structures including absolute configurations were elucidated by spectroscopic data analysis, HRESIMS data, modified Mosher's method, chemical degradation studies, ECD calculations, single crystal X-ray diffraction, and biogenic considerations in comparison with reported known analogues. Penitanzacids H-J ( 10-12 ) represent the first examples of this family with a C 3 side chain and support the proposed biosynthetic pathway in which the side chain is connected to the decalin backbone. Hatsusamides C-D ( 13-14 ) have a hybrid skeleton formed by linking a tanzawaic acid and a diketopiperazine through an ester bond. Compounds 13 and 14 exhibit weak cytotoxicity against the A549 cell line.