17β-Hydroxy-18-acetoxywithanolides from Aeroponically Grown Physalis crassifolia and Their Potent and Selective Cytotoxicity for Prostate Cancer Cells.

When cultivated under aeroponic growth conditions, Physalis crassifolia produced 11 new withanolides (1-11) and seven known withanolides (12-18) including those obtained from the wild-crafted plant. The structures of the new withanolides were elucidated by the application of spectroscopic techniques, and the known withanolides were identified by comparison of their spectroscopic data with those reported. Withanolides 1-11 and 16 were evaluated for their potential anticancer activity using five tumor cell lines. Of these, the 17β-hydroxy-18-acetoxywithanolides 1, 2, 6, 7, and 16 showed potent antiproliferative activity, with some having selectivity for prostate adenocarcinoma (LNCaP and PC-3M) compared to the breast adenocarcinoma (MCF-7), non-small-cell lung cancer (NCI-H460), and CNS glioma (SF-268) cell lines used. The cytotoxicity data obtained for 12-15, 17, and 19 have provided additional structure-activity relationship information for the 17β-hydroxy-18-acetoxywithanolides.