In vitro anti-oxidant activity, fluorescence quenching study and structural features of carbohydrate polymers from Phyllanthus emblica

The water-extracted carbohydrate polymers (WE) of Phyllanthus emblica are analyzed using chemical, chromatographic, and spectroscopic methods. Anion-exchange-chromatography of WE yielded four fractions (F1-F4) with different chemical compositions and all of them contain phenolics. The major fraction F4 possesses 50% polysaccharide and 26% phenol, and is a glycoconjugate. The antioxidant capacities of WE and F4 are comparable to standard anti-oxidants. Notably, activities of F1-F4 correlate with their phenol content. Evidence for the complexation of F4 with bovine serum albumin is presented by fluorescence quenching measurement. The results also indicate conformational change of protein at high carbohydrate polymer concentration.