Abstract

The extraction and isolation of four crude polysaccharides from Hedyotis diffusa Willd., as well as the evaluation of their antioxidant and anti-glycated activities in vitro were investigated. The whole plant of H. diffusa was extracted with hot distilled water and three fractions of crude polysaccharides, termed as 50P, 70P and 90P were obtained by graded ethanol precipitation, BP were gained by NaOH solution extracted followed by ethanol precipitation. All of the four polysaccharides were defatted with petroleum ether and protein was removed  by the Sevag reagent. Preliminary antioxidant in vitro indicated that the four crude polysaccharides showed powerful and dose-dependent scavenging abilities on DPPH· and hydroxyl radicals. For the first time, the anti-glycated activities of the four samples were studied, and they had good potential in inhibiting the non-enzymatic glycation reaction with dose-dependent effects. In particular, 90P showed even better antioxidant and anti-glycated activities than corresponding positive control. Therefore, H. diffusa crude polysaccharides have potential value on the prevention and treatment of some diseases caused by oxidant and aging, and worthy of further research and development.

Key words: Hedyotis diffusa Willd., polysaccharide, antioxidant activity, anti-glycated activity, in vitro.