A bioassay-guided fractionation and chemical investigation of the stems of Lagerstroemia indica resulted in the isolation and identification of a new triterpene glycoside, lagerindiside (1), along with nine known triterpenes (2-10). The structure of this new compound was elucidated on the basis of 1D and 2D nuclear magnetic resonance spectroscopic data analysis as well as chemical method. The cytotoxic activities of the isolates (1-10) were evaluated by determining their inhibitory effects on four human tumor cell lines (A549, SK-OV-3, SK-MEL-2, and HCT15) using a sulforhodamine B bioassay. Compounds 3 and 4 showed potent cytotoxicity on the tumor cell lines with IC50 values ranging from 3.38 to 6.29 μM.
Keywords: Cytotoxicity; Lagerstroemia indica; Lythraceae; Triterpene glycoside.