Characterization and Antioxidant Properties of OJP2, a Polysaccharide Isolated from Ophiopogon japonicus

A water-soluble polysaccharide (OJP2) obtained from the roots of Ophiopogon japonicas, was precipitated with 95% ethanol and purified by DEAE-52 cellulose anion-exchange and Sephadex G-100 gel filtration chromatography. The characteristics of OJP2 were determined by chemical analysis, high performance gel permeation chromatography (HPGPC), and gas chromatography-mass spectrometry (GC-MS). The results showed that the average molecular weight (Mw) of OJP2 was 35.2 kDa, and five kinds of monosaccharides including rhamnose, arabinose, xylose, glucose and galactose in a molar ratio of 0.5:5:4:1:10. Furthermore, the antioxidant activity of OJP2 was evaluated in H2O2-treated HaCaT cells and glucose-treated LO2 cells. The results show that OJP2 can increase the activity of SOD and NO production, and decrease the level of MDA in these two kinds of injury cells. OJP2 should be explored as a novel and potential natural antioxidant agent for use in functional foods or medicine.