Structural elucidation a complex galactosyl and glucosyl-rich pectin from the pericarp of immature fruits of Juglans mandshurica Maxim.

A glucosyl-rich pectin, JMMP-3 (Mw, 2.572 x 104 g/mol, O-methyl % = 3.62%), was isolated and purified from the pericarp of the immature fruit of Juglans mandshurica Maxim. (QingLongYi). The structure of JMMP-3 was studied systematically by infrared spectroscopy, monosaccharide compositions, methylation analysis, partial acid hydrolysis, and 1/2D-NMR. The backbone of JMMP-3 possessed a smooth region (-> 4GalA1 ->) and a hairy region (-> 4GalA1 -> 2Rha1 ->) with a molar ratio of 2: 5. The substitution of four characteristic side chains (R1-R4) occurs at C-4 of -> 2,4)-alpha-Rhap-(1 ->, where R1 is composed of -> 5)-alpha-Araf-(1 ->, R2 is composed of -> 4)-beta-Galp-(1 -> and beta-Galp-(1 ->, R3 is composed of alpha-Glcp-(1 ->, -> 4)-alpha-Glcp-(1 -> and -> 4,6)-alpha-Glcp-(1 ->, and R4 is composed of -> 5)-alpha-Araf-(1 ->, beta-Galp-(1 ->, -> 4)-beta-Galp-(1 ->, -> 3,4)-beta-Galp-(1 ->, -> 4,6)-beta-Galp-(1 -> and -> 2,4)-beta-Galp-(1 -> . In addition, the antitumor activity of JMMP-3 on HepG2 cells was preliminarily investigated.