Effects of Capsaicin and Its Analogs on the Growth of Gastric Cancer Cells and Their Structure-activity Relationships In Vitro

Capsaicin is an organic compound in chili peppers which are consumed by over one quarter of the world’s population daily. Studies have shown that capsaicin can prohibit proliferation in some cancer cells. In the present study, both gastric cancer and normal epithelial cell lines were employed and treated with capsaicin and its analogs and examined for the structure-activity relationship as well. 3-(4, 5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide yellow tetrazole (MTT) assay results showed the order of effectiveness of capsaicin analogs in the used cell culture system was as follows: dihydrocapsaicin > capsaicin > 6-gingerol > vanillin ≥ vanillylamine, and, reactive oxygen species (ROS) and malondialdehyde (MDA) contents were markedly increased; the biological activity pathway of Superoxide dismutase (SOD) and Glutathione Peroxidase (GSH-Px) was up-regulated, whereas, the catalase (CAT) activity was down-regulated by dihydrocapsaicin, capsaicin and 6-gingerol. In conclusion, the results implied that B and C region are indispensable for the anti-cancer activity of capsaicin and CAT activity down-regulation was responsible for apoptosis of gastric cancer cells induced by capsaicin and its analogs.