New withanolides from Physalis minima and their cytotoxicity against A375 human melanoma cells.

Seven previously undescribed withanolides, namely physaminilide A-G (1-7), and two artificial withanolides (8-9), along with 10 known analogues (10-19) were isolated from Physalis minima . The structures were established by spectroscopic analysis, including NMR and electronic circular dichroism (ECD) data. Cytotoxicity of all the isolates was evaluated against A375 human melanoma cells. Compounds 2, 5, 8, 10, 11 and 15 exhibited significant cytotoxic activities with IC 50 values in the range of 1.2-9.4 μM.