Marsdenia tenacissima (Roxb.) Wight et Arn is a traditional herbal medicine, which has been used for centuries
in southwest China in the treatment of cancer, neoplasia, and other diseases. The
drug made from M. Tenacissima, named as antitumor injection, had been proved high clinical effective for hepatocellular
carcinoma, lung cancer, and gastric cancer. Previous studies indicated that the main
effective components in M. Tenacissima were C21 steroidals. The aim of the present work is the elaboration of constituents and the
cytotoxic activities of C21 steroidals in the title herb. Twenty-four compounds were isolated and structurally
determined from the ethanol extract under the bioassay-guided procedure, including
sixteen C21 steroidals, three azulenes, four disaccharide derivatives, and a bisepoxyligan. There
are twelve novel compounds among them. The cytotoxic activities of C21 steroidals were evaluated using MTT assays on three human non small cell lung cancer
cells, NCI-H292, NCI-H460, and NCI-H1975 cell lines. Two C21 steroidals, TenacissosideIand Tenacigenin A, exhibited good potency against the three
cell lines with IC50 values of 0.32 and 0.97, 0.74 and 2.69, 1.59 and 7.70µM, respectively.The results
support the ethnomedicinal usage of M. Tenacissima. Acknowledgements: Thank the supporting grant for NCET-12 – 0578, 13 – 0624, 111Project
B08044 and YLDX01013.