Spirostanol pentaglycosides from the underground parts of polianthestuberosa.

Phytochemical analysis of the underground parts of Polianthes tuberosa has resulted in the isolation of four new spirostanol saponins with five monosaccharides (1-4). Their structures were determined by spectroscopic analysis, including extensive 1D and 2D NMR data, and the results of hydrolytic cleavage. The cytotoxic activities of 1-4 against HL-60 human promyelocytic leukemia cells and HSC-2 human oral squamous cell carcinoma cells are reported.