Antitumor Activity of Extracts from Oxytropis falcata Bunge on human Hepatocellular Carcinoma SMMC-7721 Cells In Vitro and in H22 Bearing Mice In Vivo

Oxytropis falcata Bunge is widely used as one of the “three anti-inflamatory drugs” and is considered to be the “king of herbs” in Chinese Tibetan medicine. For thousands of years it has been used to treat inflammation, pyreticosis and bleeding [1]. In the present study, we investigated the antitumor effects of O. falcata extracts on human hepatocellular carcinoma SMMC-7721 cells in vitro and in transplanted murine H22 tumors in vivo. Cell proliferation, morphological changes, cell cycle distribution and apoptosis in SMMC-7721 cells were determined and tumor growth inhibition in H22 tumors was investigated. MTT assay revealed that essential oil fraction (EOOF) and total flavonoids fraction (TFOF) of O. falcata inhibited proliferation of SMMC-7721 cells in a dose-dependent manner. Growth inhibition in H22 solid tumors was significantly pronounced after being treated with TFOF. Hoechst 33258 staining of SMMC-7721 cells indicated that TFOF caused typical characteristics of apoptotic programmed cell death, such as cell shrinkage, apoptotic body formation and nuclear fragmentation. Cell cycle distribution was analyzed by flow cytometry with propidium iodide (PI) and annexin V-FITC/PI double staining that significant solid tumor inhibition occurred in H22 transplanted mice, cell cycle was arrested at G1 phase, and induction of apoptosis occurred in SMMC-7721 cells when subjected to TFOF. These results suggest that TFOF promotes apoptosis in SMMC-7721 cells and inhibits H22 tumor growth, resulting in a potential antitumor effect on hepatic cancer. Acknowledgements: Support for this research from the National Natural Science Foundation of China for Youth (Grant No.30902012) is gratefully acknowledged. References: [1] Mao JZ, Luo DS, Wang ZH (1986) Jing Zhu herbal, Shanghai Science and Technology Press. Shanghai.