Chemical composition and free radical scavenging activities of a sulphated polysaccharide extracted from abalone gonad (Haliotis Discus Hannai Ino)

Crude polysaccharides (CPs) were prepared from Haliotis Discus Hannai Ino gonad by protease-hydrolysis combining boiling-methanol extraction. They were purified to homogeneity by gel-filtration chromatography on Sephacryl-S 100 and Sephacryl-S 200, and semi-preparation high performance liquid chromatography (semi-RP-HPLC) equipped with a SOURCE 30Q anion exchange column. The sulphated polysaccharide obtained, named as PAGP, has an average molecular weight (MW) of 12.5 kDa determined by HPLC coupled to a TSK-gel G4000PWXL column. Chemical composition analysis indicated it was composed of carbohydrate (50.7%), sulphated group (31.1%), aminohexose (7.1%), aronic acid (6.2%) and protein (2.0%). The carbohydrate part of PAGP was composed of rhamnose (Rha), fucose (Fuc), and galactose (Gal) in molar ratio of 1.0:1.6:2.3. The protein part of PAGP contained 13 kinds of amino acids. Antioxidant assays demonstrated that PAGP possessed stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical and hydroxyl radical scavenging activities than positive controls vitamin C (VC) and vitamin E (VE).