PURIFICATION, CHARACTERIZATION AND IN VITRO ANTIOXIDANT ACTIVITIES OF POLYSACCHARIDE FRACTIONS ISOLATED FROM THE FRUITS OF PHYSALIS ALKEKENGI L.

Abstract

The water-soluble crude polysaccharide PAPS, isolated from the fruits of Physalis alkekengi L. by hot water extraction and ethanol precipitation, was fractionated by diethylaminoethyl-cellulose ion exchange chromatography and Sephacryl S-300 gel filtration chromatography on ATKA explore 100 purifier, giving four polysaccharide fractions coded as PAPSA-a, PAPSA-b, PAPSB-c and PAPSB-d. Their chemical and physical characteristics were determined by chemical methods, gas chromatography and high performance size exclusion chromatography. The in vitro antioxidant activities of polysaccharides were studied by various antioxidant assays. Experiment results showed that all fractions exhibited antioxidant activity in a concentration-dependent manner, and PAPSB-c and PAPSB-d had stronger antioxidant ability than PAPSA-a and PAPSA-b in all the tests. The polysaccharide fractions can be developed as new antioxidant agents. PRACTICAL APPLICATIONS More and more researches are focused on natural products including vegetables and wild fruits sources. Physalis alkekengi is a kind of wild fruit in north of China, famous for its good taste and high nutritional quality. But, at present, the fruits of P. alkekengi are not fully utilized. This work reported on isolation and characterization of polysaccharides from P. alkekengi, and the in vitro antioxidant activities were studied by various antioxidant assays. The objective of this research work was to extend the potential use of P. alkekengi fruits in functional food or antioxidant biomedicine.