Antitumor effect and molecular mechanism of antioxidant polysaccharides from Salvia miltiorrhiza Bunge in human colorectal carcinoma LoVo cells.

Salvia miltiorrhiza Bunge polysaccharides (SMP) was comprehensively investigated in this study. The polysaccharides were extracted by the method of water boiling and ethanol precipitation with high purity. The monosaccharide composition of SMP was characterized using the established HPLC-UV protocol with PMP precolumn derivatization, and the results indicate that the polysaccharides are mainly composed of d-galactose (Gal), d-glucose (Glc) and d-galacturonic acid (GalUA), and their mole percentages are 64.5%, 31.1% and 4.4%, respectively. In addition, the antioxidant potential of SMP was evaluated in terms of reducing power, scavenging ability against DPPH, superoxide and hydroxyl free radicals. The results indicate that polysaccharides from S. miltiorrhiza Bunge possess versatile antioxidant activities in a dose-dependent manner. Furthermore, SMP is observed with high inhibition ratio against LoVo cells (typical tumor cells) in both dose- and time-dependent manners. FCM analysis demonstrates that SMP is able to induce apoptosis of LoVo cells, arrest the cell cycle at S phase, as well as elevate the intracellular reactive oxygen pressure. These findings for the first time reveal the potential anti-tumor mechanism of SMP, suggesting that SMP may serve a natural anticancer agent with lower cost and cytotoxicity, as well as a bioactive factor for functional food development.