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.