Abstract: Objective: To explore the effect of Sphallerocarpus gracile polysaccharides (SGP) on apoptosis induction and proliferation inhibition of HepG2 and P388 cells as well as the lifespan extension of mice treated with SGP. Methods: HepG2 and P388 cells were co-cultured in the presence of SGP in this study. The inhibitory effect of SGP at different concentrations on the proliferation of HepG2 and P388 was evaluated by MTT assays. The SGP-induced apoptosis and cell cycle change of HepG2 and P388 were analyzed by flow cytometry. Meanwhile, the extension of lifespan of P388 mice treated with SGP was determined. Results: SGP revealed a significant anti-proliferation effect on HepG2 and P388 in vitro. The inhibition rate of SGP treatment for 48 h at the concentration of 200 mg/(kg·d) against HepG2 was 37.5% (P＜0.01). The inhibition rates against P388 at 150 and 200 mg/(kg·d) after 48 h of treatment were both over 38% (P＜0.01). In addition, SGP obviously inhibited the growth of implanted HepG2 in mice with an inhibitory rate of higher than 40%. Moreover, SGP induced the apoptosis of HepG2 and block HepG2 at the G1 phase. Furthermore, SGP prolonged the life of P388-bearing mice with a lifespan extension rate of 10%. Conclusion: SGP has an outstanding anti-cancer effect in mice and can effectively inhibit the proliferation of HepG2 and P388 cells and induce the apoptosis of HepG2 cells.

Key words: Sphallerocarpus gracilis polysacchorides (SGP), HepG2 cell, P388, proliferation inhibition, apoptosis