Scalusamides A-C, new pyrrolidine alkaloids from the marine-derived fungus Penicillium citrinum

Three new pyrrolidine alkaloids, scalusamides A-C (1-3), were isolated from the cultured broth of the fungus Penicillium citrinum, which was separated from the gastrointestine of a marine fish, and the structures were elucidated by spectroscopic data. The absolute stereochemistry of C-2 in the pyrrolidine unit was determined by HPLC analysis of a Marfey's derivative of the hydrolysate of 1, while that of 2 and 3 was assigned by comparison of spectroscopic data of 3 and reductive products of 1 and 2. On the other hand, each of 1-3 was found to be a mixture of epimers at C-7. Scalusamide A (1) exhibited antifungal and antibacterial activities.