Withanolides from Physalis angulata var. villosa and the Relative Configurational Revision of Some Known Analogs

Physalis angulata var. villosa is a plant possessing abundant withanolides, but in-depth research is lacking. In our ongoing study of P. angulata var. villosa, 15 previously undescribed withanolides ( 1 – 15 ), along with 21 known analogs ( 16 – 36 ), were isolated from the whole plant. The structures of the withanolides ( 1 – 15 ) were elucidated based on analysis of their 1D and 2D NMR, HRESIMS, and ECD data. Additionally, the application of γ-gauche effects with the help of ROESY correlations led to the formulation of empirical rules for withanolides with 14-OH/15-OAc to rapidly determine the 14-OH orientations, making it possible to propose configurational revisions of 19 previously reported analogs ( 1′ – 19′ ). Withanolides 1, 4 – 6, and 10 showed potent cytotoxic activities against three human cancer cell lines (HCT-116, MDA-MB-231, and A549).