Antioxidant, antiproliferative, and pro-apoptotic activities of a saponin extract derived from the roots of Panax notoginseng (Burk.) F.H. Chen.

Dietary and medicinal uses of Panax notoginseng have been associated with reduced risk of cancer. This study was designed to investigate the profiles of P. notoginseng saponin extract (PNSE), the major bioactive ingredients in P. notoginseng (Burk.) F.H. Chen, by high-performance liquid chromatography, and, for the first time, the anticancer effect of PNSE in the human colon cancer cell line LoVo was further evaluated. The major saponins present in PNSE were ginsenosides Rg1 (31.1%) and Rb1 (34.4%), and the total content of the eight saponins identified (notoginsenoside R1, ginsenosides Rg1, Re, Rb1, Rc, and Rd, and isomeric ginsenosides Rb2 and Rb3) was 81.7%, indicating that it was a highly purified standardized saponin extract. Furthermore, PNSE was found to have a markedly cytotoxic effect and antiproliferative activity against the LoVo cell line in a dose- and time-dependent manner. Flow cytometry analysis demonstrated that PNSE caused cell cycle arrest at S phase. Moreover, PNSE was found to possess antioxidative capacities in the 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay and hydroxyl radical scavenging assay in vitro. Taken together, the present results suggest that naturally occurring PNSE may provide significant natural defense against human colon cancer.