Three new withanolides including nicphysatone A (1), an unusual withanolide lactone possessing a disconnected C-13 to C-17 linkage within the steroidal nucleus; and nicphysatone B-C (2–3) were isolated from the persistent calyx of Nicandra physaloides. Compounds 1–3 showed no cytotoxic activity in these cell lines with IC50 > 40 μM.
Chemical investigation on ethyl acetate extract of the calyces of Nicandra physaloides resulted in the isolation of three new withanolides named as nicphysatone A (1), nicphysatone B (2), nicphysatone C (3), together with five known withanolides, nic 17 (4), nic 7 (5), nic 2 (6), withahisolide G (7) and nicaphysalin B (8). The structures were determined by comprehensive spectroscopic experiments. The discovery enriched the diversity of natural withanolides and could serve as scaffolds for the synthesis of more potent modified withanolides.