Cholesaponins A-F, Six New Rare Cholestane Saponins Including Two Unprecedented 14-Methyl C28 Cholestane Saponins from Solanum Xanthocarpum

Phytochemical investigation of Solanum xanthocarpum fruits resulted in the isolation of eight rare cholestane saponins, including six new ones (1–6) and two known ones (7–8). Especially, cholesaponins A and B (1–2) were unusual 14-methyl C28 cholestane saponins discovered for the first time. The chemical structures of 1–6 were characterized by extensive 1D NMR and 2D NMR and mass analyses. The bioassay screening revealed that most compounds showed varying cytotoxic activity degrees against five human cancer cell lines (A-549, HepG2, MGC-803, LN-229, and SMMC-7721).