Immunomodulatory activity of non starch polysaccharides isolated from green gram (Vigna radiata)

Green gram, rich in dietary fiber is known to enhance the function of immune system. However information pertaining to the immunomodulatory potential of its non starch polysaccharides (NSPs) is scanty. Hence, five different NSPs were extracted successively using water (WSP), hot water (55 degrees C, HWSP), EDTA (0.5%, Pectins) and alkali (10%, Hemicellulose A and B) which varied in their arabinose to galactose ratio, sugar, protein, uronic acid contents, molecular weight distribution and immunomodulatory activity. Hemicellulose B was relatively rich in carbohydrate content (similar to 95%) and also possessed potent immunomodulatory activity among the various NSPs. Hemicellulose B was further fractionated on DEAE-cellulose column into six different fractions by eluting step-wise with water, ammonium carbonate (0.1, 0.2, 0.3 MAC) and sodium hydroxide (0.1 and 0.2 M NaOH). 0.1 MAC eluted fraction was found to be the major one amounting to 50% yield and showed relatively significant (p < 0.001) activity towards splenocyte proliferation and macrophage activation as compared with rest of the DEAE eluted fractions.