New steroidal saponins from the roots of Solanum melongena L.

Phytochemical investigation of the roots of Solanum melongena L. resulted in the isolation of six new steroidal saponins, including five new cholestane saponins (1-5) and one new steroidal alkaloid (6), along with one new natural product (7) and three know steroids (8-10). The structures of all isolated compounds were determined by 1D and 2D NMR experiments and by comparison of their spectroscopic and physical data with literature values. The inhibitory activities on nitric oxide (NO) production stimulated by lipopolysaccharide (LPS) in a RAW 264.7 cell line were assayed for all the isolated compounds. Compounds 1, 2 and 4-9 exhibited moderate inhibition of NO production with IC50 values ranging from 12.6 to 59.5 mu M.