Isolation, purification and in vitro anti-tumor activity of polysaccharide from Ginkgo biloba sarcotesta

Isolation and purification of polysaccharide from Ginkgo biloba sarcotesta by cellulose DEAE-52 and Sephadex G-100 column chromatography were performed in this study. Four water-soluble polysaccharides named GBEPP11, GBEPP22, GBEPP33 and GBEPP44 were obtained and their anti-tumor activities in vitro were tested by MTT assay. GBEPP44 with molecular weight (MW) 9.5 × 105 Da, GBEPP33 with MW 3.1 × 105 Da and GBEPP22 with MW 4.8 × 104 Da were composed of rhamnose, glucose, galactose with a molar ratio of 16:10:0.96, 2.64:1:1.43 and 37.01:1:8.46, respectively. GBEPP11 with MW 3.4 × 103 Da was composed of rhamnose, glucose with a molar ratio of 1.9:1. MTT assay revealed that the polysaccharides had anti-tumor activity in a dose-dependent manner. The inhibitory rate of the polysaccharides on U937 was the highest among the three cancer cells, which increased as the MW decreased. Furthermore, the activity of acetylated GBEPP11 was higher than that of GBEPP11 and the inhibitory rate reached 78.97% at the concentration of 640 μg/mL.