Abstract:The polysaccharides of Piteguo (PTGP1) extracted by water-extraction and ethanol-precipitation methods were purified by Soxhlet extraction, Sevag method andDEAE-52 anion exchange column chromatography. The structure, composition and molecular weight of PTGP1 were analyzed by ultraviolet-visible spectra (UV-VIS), infrared spectrum (IR), scanning electron microscopy (SEM), gas chromatography tandem mass spectrometer (GC-MS) and high performance size exclusion chromatography multiangle laser light scattering (HPSEC-LLS). The in vitro antioxidant activities of PTGP1 were determined by the total reducing power, DPPH, superoxide radicals, hydroxyl radicals scavenging assays and the inhibition rate of malondialdehyde (MDA) in mice liver homogenate. Results showed that PTGP1 was a reducing sugar without starch and anthocyanins, whose surface was of holes fold fibrous structure. PTGP1was mainly consisted of rhamnose, arabinose, xylose, mannose, glucose and galactose, with the molar ratio of 3.06:2.32:1.56:4.87:3.28:2.18 in the form of pyranose containing α-glycosidic bond. HPSEC-LLS analysis showed that the PTGP1 was composed of three different polymers, whose average molecular weight was 5.81×105 Da and the main composition content was 76%. Oxidation test indicated that the total reduction ability of PTGP1 was 0.45 times compared with VC, the half inhibit concentration (IC50) of PTGP1 for scavenging hydroxyl free radicals, superoxide anion and DPPH free radicals were 1.24 mg/mL, 1.05 mg/mL and 2.13 mg/mL, respectively, which could effectively inhibit lipid peroxidation induced by hydroxyl free radicals, as well as the formation of MDA in mice liver homogenate.
