Steroidal alkaloid glycosides and phenolics from the immature fruits of Solarium nigrum

Solanum nigrum L. (also called as European black nightshade) has been traditionally used as folk medicine and food in some regions. Phytochemical investigations of the immature fruits of S. nigrum yielded five steroidal alkaloid glycosides (1-5), including an unprecedented nor-spirosolane type steroidal alkaloid with a five membered ring A (1) and two novel spirosolane type steroidal alkaloid glycosides (2, 3), together with eight known phenolic compounds (6-13). Their structures were elucidated on the basis of spectroscopic and chemical methods, including IR, NMR, HR-ESI-MS, and GC analyses. Five steroidal alkaloid glycosides were tested for their potential antiproliferative effects against HL-60, U-937, Jurkat, K562, and HepG2 cell lines and inhibitory activities on nitric oxide (NO) production induced by lipopolysaccharide (LPS) in a macrophage cell line RAW 264.7. Compound 1 exhibited significant inhibition on NO production with an IC50 value of 23.4 +/- 2.0 mu M, compared to positive control indomethacin (IC50, 47.40 +/- 4.50 mu M). Compound 4 exhibited significant cytotoxicity against all tested cell lines.