Phytochemical constituents and cytotoxic activities of the traditional herbal medicine Marsdenia tenacissima

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.