Capsisteroids A-F, withanolides from the leaves of Solanum capsicoides

A known withanolide steroid cilistol G (1) and six new withanolides, capsisteroids A-F (2-7), were isolated from the EtOAc extract of the leaves of Solanum capsicoides. The structures of compounds 1-7 were elucidated by extensive spectroscopic analysis, including 2D NMR spectroscopy (COSY, HSQC, HMBC, and NOESY). The structure of 1 was further confirmed by a single-crystal X-ray diffraction analysis. These compounds were found not to be cytotoxic toward a limited panel of cancer cell lines. Further, the anti-inflammatory activity of compounds 1-7 was studied by measuring their ability to suppress superoxide anion generation and elastase release in fMLP/CB-induced human neutrophils.