Isolation, purification, immunological and anti-tumor activities of polysaccharides from Gymnema sylvestre

Five water-soluble polysaccharides, including GSP11 (xylose:glucose = 1:2.47), GSP22 (rhamnose:glucose: galactose = 1.6:1:1.22), GSP33 (rhamnose:glucose:galactose = 1:1.5:1.1), GSP44 (xylose:glucose:galactose = 1:1.03:1.2) and GSP55 (rhamnose:xylose:glucose:galactose = 1:1.21:1.81:2.58), were obtained from Gymnema sylvestre and tested for their immunological and anti-tumor activities. The molecular weights of the five water-soluble polysaccharides were 5.3 x 10(4), 5.4 x 10(5), 9.5 x 10(5), 1.0 x 10(6) and 1.9 x 10(6) Da, respectively. Immunological activity tests revealed that both crude and deproteinated polysaccharides (GPS) possess good immunological activities, especially on blood serum hemolysin formation at 300 mg/kg. MTT assays revealed that all samples possessed anti-tumor activities in a dose-dependent manner except for GSP22 in AGS cells. At a concentration of 640 mu g/mL, GSP11 and GSP33 showed good activities in U937 cells, with inhibitory rates of 78.6% and 83.8%, respectively, and GSP22 showed good activity in SGC cells with an inhibitory rate of 78.2%. (C) 2012 Elsevier Ltd. All rights reserved.