Antimycobacterial physalins from Physalis angulata L. (Solanaceae)

Crude extracts and fractions from aerial parts of Physalis angulata have been bioassayed for antimycobacterial activity. Fraction Al-29-12 containing physalins B, F and D exhibited a minimum inhibitory concentration value (MIC) against Mycobacterium tuberculosis H(37)Rv strain of 32 mug/mL. Purified physalin B and physalin D were also tested showing MIC values against Mycobacterium tuberculosis H37Rv strain of >128 mug/mL and 32 mug/mL respectively, suggesting that physalin D plays a relevant role in the antimycobacterial activity displayed. Structural elucidation of both physalins D and B was based on detailed C-13 and H-1 NMR spectral analysis with the aid of 2D-correlation spectroscopy (H-1-H-1, COSY, HSQC and HMBC). The assignment of the C-13 chemical shift for physalin D is reported here for the first time. Copyright (C) 2002 John Wiley Sons, Ltd.