Penicurvularins A and B, macrolides from an ascomycete fungus Alternaria sp.

Two new macrolides, penicurvularins A and B (1 and 2), and the three known compounds (3-5) were isolated from cultures of the ascomycete fungus Alternaria sp. Their structures were elucidated primarily by NMR experiments. The absolute configuration of 1 was assigned from electronic circular dichroism calculations. Compounds 1 and 5 are active against aquatic pathogenic bacteria Vibrio alginolyticus and V. harveyi with MIC values ranging from 4 to 8 µg mL-1, while compound 5 is cytotoxic against tumor cell lines Huh7, 786-O, and 5673 with IC50 values of 11.6, 10.7, and 3.5 µM, respectively.