The Extract And Purifying Of The Ginkgo Biloba Leaf Polysaccharide And The Study Of Its Molecule Structure

A water soluble crude polysaccharide extracted by alcohol has been isolated from the water-boiled dry mature autamn leaf of Ginkgo Biloba. It is a mixture of heteroglycan composed of Glc Man Gal Rha GalA in molar ratio of 1.65:1.38:2.2:1.35:1,and little Ara. After graded by freezing and purified by the combined deprotionization methods of enzyme and sevage, it (PGBL₃) was homogeneous by tests: Gel filtration on Sephadex G-75,Cellulose acetate pellicle electrophoresis ,Determination of specific rotation and HPLC analyse.The identification of purificaton implied that PGBL₃ was uniform on both molecular weight and polarity, furthmore its molecular weight was about 10 thousand by gel filtration, and it was glucan by G.C. analysis. PGBL₃ (Polysaccharide of Ginkgo Biloba Leaf) obtained by gradation and purifaction contain Gal Man Glc Ara Rha GalA, in molar ratio of 6:12.4:11.7:14.6:16.8:1 . Partial hydrolysis with acid,Periodate oxidation,Smith degradation, I.R.,and Methylation were used on the structure analysis of PGBL₃.After acetylation, the methylated productions were analyzed by G.C.- M.S. The results revealed that PGBL₃ was a kind of highly branched structure. The main chain of PGLB₃ was composed of Gal(1→6) and Gal(1→3,6)linked alternately. Some Glc(1→3,4) Glc(1→2,4) as insert main chain .Some Glc(1→3,6)get the core side chain.So its possible repeated unit was: —[—1Gal₆——1Gal₆——1Gal₆——1Gal₆——1Gal₆—]n— ︱3 ︱3 ︱3 Glc...