文摘
A pair of unusual benzannulated 6,6-spiroketal enantiomers [(鈭?-1 and (+)-1] and three new biogenetically related compounds (2鈥?b>4), together with two known related analogues (5 and 6), have been isolated from a mangrove fungus, Penicillium dipodomyicola HN4-3A. Their structures were elucidated on the basis of spectroscopic analysis (1D and 2D NMR data) and X-ray crystallography. The absolute configurations of enantiomers (鈭?-1 and (+)-1 were determined using quantum chemical calculations of the electronic circular dichroic (ECD) spectra. Compounds 2 and 3 exhibited strong inhibitory activity against Mycobacterium tuberculosis protein tyrosine phosphatase B (MptpB) with IC50 values of 0.16 卤 0.02 and 1.37 卤 0.05 渭M, respectively.