Separation, Purification and Anti-tumor Activity of Polysaccharides from Perilla frutescens Seeds

In order to explore the anti-tumor activity of Perilla frutescens seed polysaccharide (PFSP), the crude polysaccharide was obtained from Perilla frutescens seeds by traditional solvent extraction and purified by DEAE-52 cellulose and dextran G-100 column chromatography, and the effect of the purified polysaccharide on the immune system of H₂₂ tumor bearing mice was determined. The results showed that the yield of the crude polysaccharide was 8.38%. After separation and purification, three polysaccharide fractions, named PFSP-1, PFSP-2 and PFSP-3, were obtained. PFSP-1 was composed of mannose, galactose, xylose and arabinose (at a molar ratio of 0.01:0.06:0.11:0.81). PFSP-2 was composed of mannose, xylose and arabinose (at a molar ratio of 0.28:0.28:0.41). PFSP-3 was composed of rhamnose, glucuronic acid, glucose, galactose, xylose and arabinose (at a molar ratio of 0.013:0.024:0.040:0.080:0.120:0.700). The three polysaccharides all displayed absorption peaks characteristic of polysaccharides and were identified as pyran-type polysaccharides.The anti-tumor effect of PFSP-2 was significantly higher than that of PFSP-1 and PFSP-3 (P < 0.05). Furthermore, PFSP-2 could significantly reduce the concentrations of lactate dehydrogenase and aldolase and interleukin (IL)-10 (P < 0.05), increase the concentrations of IL-2 and tumor necrosis factor α, down-regulate the expression of antiapoptotic protein Bcl-2, and up-regulate the expression of apoptotic protein Bax compared with the model group (P < 0.05). These results indicate that PFSP-2 can inhibit the growth of tumor cells in vivo by improving the immune system of mice.