Structure Analysis of Pectin SB1-1 from the Root of Panax ginseng

A water-soluble pectin SB1-1 was isolated and purified from the root of Panax ginseng C. A. Mey. The HPLC analysis indicates that SB1-1 is homogenous. Its molecular weight was estimated via gel filtration to be 10000. The GC analysis indicated that it contains the monosaccharides of GalA, Gal, Ara and Rha. Their molar ratio is 2.10∶1.00∶0.12∶0.13. Partial hydrolysis with acid, pectinase treatment, periodate oxidation, Smith degradation, methylation analyses, GC/MS analyses and NMR analyses were used for the structure analyses of SB1-1. The results reveal that SB1-1 has a lower branched structure. The main chain is composed of GalA and Gal; the inner part is α-1,4-linked-GalA; the border is 1,4-linked-Gal. Some of the 1,4-linked-GalA and 1,4-linked-Gal residues are substituted at O6. On an average, there is one branch for every ten hexose residues. The side chain is composed of 1,6-linked-Gal and 1,3,6-linked-Gal. The nonreduced end is composed of Rha, Ara and Gal. The main glycosidic link of SB1-1 has an α configuration.