Isolation, structure elucidation, and antimycobacterial properties of dimeric naphtho-gamma-pyrones from the marine-derived fungus Aspergillus carbonarius

摘要

Two new dimeric naphtho-gamma-pyrones, compounds 1 and 2, were isolated from the AcOEt extract of the fungal strain WZ-4-11 of Aspergillus carbonarius, together with eight known analogues, including 10,10'-bifonsecin B (3), 6'-O-demethylnigerone (4), nigerone (5), isonigerone (6), fonsecin (7), rubrofusarin B (8), TMC 256A1 (9), and flavasperone (10). Their structures were elucidated by means of UV, CD, IR, and 1D- and 2D-NMR spectroscopy, in combination with HR-MS analysis. The fully assigned H-1- and C-13-NMR data of 3, and the C-13-NMR data of 6 are reported for the first time. Compounds I and 2 showed weak anti mycobacterial activities against Mycobacterium tuberculosis H37Rv, with MIC values of 43.0 and 21.5 mu M, resp.