Antioxidant activity of Momordica charantia polysaccharide and its derivatives

Momordica charantia polysaccharide (MCP) was extracted by hot water and chemically modified to obtain phosphorylated Momordica charantia polysaccharide (P-MCP) with degree of substitution 0.12 and sulfated Momordica charantia polysaccharide (S-MCP) with degree of substitution 0.45. The sugar content of the three polysaccharides was determined by phenol sulfuric acid method, 74.0%, 68.1% and 59.8% respectively. The scavenging ability of three polysaccharides to superoxide anion, hydroxyl radical and DPPH radical, as well as their anti-lipid peroxidation and reduction ability were determined. The results showed that the antioxidant activity of polysaccharides varied with different chemical modifications.