Abstract: Glycan was isolated on Sephadex G-100 column after glycoconguate LbGp4 was released by β--elimination, then desalted on Sephadex G-25 and named LbGp4-OL. The linkage between the glycan and the core protein backbone was Olinkage. The molecular weight of LbGp4-OL was 180800. The result of its elemental analysis was C39.1%, H5.72%, N 0%. Component analysis showed that it was composed of Rha, Ara and Gal in a molar ratio of 0.05 : 1.33 :1. The structure of repeat unit of LbGp4-OL was deduced by methylation analysis, partial acid hydrolysis and ¹H, ¹³C NMRspectroscopy of the original glycan and products of its partial hydrolysis. Methylation analysis of LbGp4-OLindicated that highly branching unit in LbGp4-OLwas →3,4)Gal(1→, the major non reducing end was Ara(1→. LbGp4-OL' was obtained by partial acid hydrolysis. Comparing the results of methylation analysis of LbGp4 with that of LbGp4-OL', we can deduced that the main chain of LbGp4-OLwas composed of →4)Gal(1→. ¹H and ¹³C NMRspectra of LbGp4-OLand LbGp4-OL' indicated that Ara(1→ was α-furanose, →3)Ara(1→ and →5)Ara(1→ were β- furanose, all the Gal were β- pyranose, Rha(1→ was α-pyranose, →3)Ara_p(1→ was α-pyranose. Immunoactivity studies of LbGp4 and its glycan showed that LbGp4 and LbGp4-OLnot only enhanced the splenocyte proliferation in normal mouse, but also improved the reducing immune function in the senescense accelerated mouse. It demonstrated that LbGp4 and LbGp4-OLpossess a direct effect of splenocytl proliferation. In addition, the direct elevating action of LbGp4-OLon splencyte prolifexration was stronger than that of LbGp4. So it pointed out that the glycan play an important role in the immunopharmcological activity of glycoconjugate.

Key words: Lycium barbarum L, Glycoconjugate, Structure, Immunoactivity