Research On The Separation, Purification Of Glycoconjugate LbGp1 From Fruit Of Lycium Barbarum L. And The Structural Characterization Of Its Glycan

Lycium barbarum L. is a famous traditional Chinese medicine which has the function of nourishing both the liver and kidney, producing nourishing essence and enhancing vision. Recent research indicated that the polysaccharides were the dominant active components in Lycium barbarum L.. In this study, we focused on the isolation, purification, physicochemical properties, structural characterization and biological activities of a glycoconjugate LbGp1 from fruit of Lycium barbarum L.. The main results were summarized as follows:1. Isolation, purification and physicochemical properties of glycoconjugate LbGp1Crude polysaccharide was obtained from the fruit of Lycium barbarum L. by water extraction and ethanol precipitation. Then the glycoconjugate LbGp1 was purified by DEAE-Cellulose column chromatography followed by Sephadex G-100 column chromatography from the crude polysaccharide. The physicochemical properties of LbGp1 were determined by HPLC, GC, IR and spectrophotometer (Table 1).2. Structural characterization of the glycan of LbGp1The glycan was then obtained by Pronase E digestion, and named LbGp1-OL. By the means of methylation analysis, partial hydrolysis, and GC-MS, the results indicated that LbGp1-OL was a branched polysaccharide. The backbone of the glycan was proposed as→4)Gal(1→6)Gal(1→6)Gal(1→repeating unit, with sidechains attached to the C3 position of some Gal residues. The→3)Gal(1→,→2)Aral(1→and→3)Ara(1→constituted the side chains, and terminal was Ara residue. LbGp1 belonged to arabinogalactan.3. In vitro antioxidant activity and anti-tumor activity assay of LBP and LbGp1The superoxide radicals (O₂·^-) scavenging power of crude polysaccharide LBP and glycoconjugate LbGp1 were evaluated with self-oxidation of 1,2,3-phentriol assay. Both LBP and LbGp1 could scavenge the O₂·^-, however, compared to LBP, LbGp1 had a weaker scavenging activity for O₂·^-.MTT method was carried out to detect the inhabitation activity of LBP and LbGp1 to human hepatoma carcinoma cell SMMC-7721. The results showed that neither LBP nor LbGp1 had pronounced inhabitation activity.