Bioactive steroidal alkaloids from the fruits of Solanum nigrum

The investigation of the fruits of Solanum nigrum led to the isolation of four previously undescribed steroidal alkaloids, named solanine A, 7 alpha-OH khasianine, 7 alpha-OH solamargine and 7 alpha-OH solasonine, together with six known ones. The structures of the isolated compounds were elucidated unambiguously by spectroscopic. data analyses and chemical methods. Solanine A represents an unusual steroidal alkaloid with an unprecedented 6/5/6/5/5/6 hexacyclic ring system, and its structure was confirmed by X-ray single crystal diffraction analysis. Compounds 2-4 were rare naturally occurring steroidal alkaloid glycosides bearing a hydroxyl group at C-7 position. Solanine A showed the most potent inhibitory activity against the LPS-induced NO production in murine RAW264.7 macrophages with an IC50 value of 3.85 +/- 0.71 mu M and significant cytotoxicity against MGC803, HepG2 and SW480 cancer cell lines with IC50 values of 6.00 +/- 0.52 mu M, 9.25 +/- 0.49 mu M and 6.23 +/- 0.26 mu M, respectively. (C) 2018 Elsevier Ltd. All rights reserved.