Triterpene glycosides from the aerial parts of Elsholtzia penduliflora W. W. Smith and their cytotoxic activity

Bio-guided fractionation of the 80% ethanol extract of the aerial parts of Elsholtzia penduliflora W. W. Smith (Lamiaceae) led to the isolation of seven new triterpene glycosides, i.e., pendulosides A-G (1-7), and one known compound (8). Their structures were determined based on extensive spectroscopic analysis, including one- and two-dimensional nuclear magnetic resonance spectroscopy, high-resolution electrospray ionization mass spectroscopy, and the results of hydrolytic cleavage. Compounds 1, 3-5, and 7-8 were tested for cytotoxic activity against two human cancer cell lines in vitro using the MTT assay method. Among them, two compounds (3 and 7) displayed significant cytotoxicities against human lung cancer (A549) cells with IC50 values of 9.01 ± 1.52 μM and 6.18 ± 1.06 μM, respectively, and human breast cancer (MCF-7) cells with IC50 values of 10.98 ± 1.76 μM and 6.82 ± 1.09 μM, respectively. The results suggest that compounds 3 and 7 might be useful for the therapeutic study of cancer.