Philadelphicalactones C and D and other cytotoxic compounds from Physalis philadelphica

Two new withanolides, philadelphicalactone C (1) and philadelphicalactone D (4), along with the known withaphysacarpin (3), ixocarpanolide (5), philadelphicalactone A (6), and ixocarpalactone A (7) were isolated from the aerial parts of Physalis philadelphica Lam. Structures of these compounds were determined by spectroscopic analyses and that of philadelphicalactone C (1) was confirmed by X-ray crystallographic analysis. Evaluation of the cytotoxic activity of all isolates and the derivative 2 against a panel of human cancer cell lines indicated a potent activity of compounds 2, 3, 6, and 7.

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► Two new and four known withanolides were isolated from Physalis philadelphica.
► The new compounds are 24-hydroxywithanolides.
► Five of the isolated compounds showed cytotoxic activity against a panel of six human cancer cell lines.
► Withaphysacarpin (3) showed the most potent cytotoxicity with IC50 values <1.0 μM in five of the cell lines.
► The diacetyl derivative of 1 also showed a strong activity.