Macrostemonoside A (MSS.A), an active steroidal
saponin from Allium macrostemon Bung has been shown to possess anti-coagulation and anti-
obesity effects. However, the functional role of MSS.A on
tumor growth has not been elucidated. We found that MSS.A significantly inhibited human
colorectal cancer cell growth in Caco2 and SW480 cells. Incubation of SW480 cells with MSS.A for 48 h resulted in cell cycle arrest. Moreover, MSS.A dose-dependently induced apoptosis in SW480 cells as shown by increased AnnexinV positively stained cell population,
caspase activation, increased pro-apoptotic and reduced anti-apoptotic Bcl-2 family
protein levels. Treatment of SW480 cells with MSS.A resulted in increased
reactive oxygen species (ROS) generation. However, pre-incubation of SW480 cells with
antioxidant N-acetylcysteine (NAC) attenuated the ROS generation and anti-
colorectal cancer activities of MSS.A. Lastly, intra-peritoneal
injections of MSS.A significantly inhibited
tumor formation in BALB/c nude mice
carcinogenesis xenograft model by reduced
tumor volume and
tumor weight when treated at dosages of 10, 50 or 100mg/kg daily for 35 days compared with PBS control. Taken together, our results indicate that MSS.A suppressed
colorectal cancer growth and induced cell apoptosis by inducing ROS production, and that MSS.A may have therapeutic relevance in the treatment of human
colorectal cancer.