Structural characterization, antioxidant and antimicrobial activity of water-soluble polysaccharides from bamboo
Zhuqian Xiao1, Qiang Zhang1, Jing Dai2
1Zhejiang Provincial Collaborative Innovation Center of Agricultural Biological Resources Biochemical Manufacturing, Zhejiang University of Science and Technology, Hangzhou 310023, PR China; College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, PR China.
Abstract:
One water-soluble neutral polysaccharides (NPs), with an average molecular weight of 5.77 × 103 Da, was isolated from bamboo (Phyllostachys pubescens Mazel) leaves and the yield was 10.2% based on weight of raw material. Successively, two fractions (NPs-A and NPs-B) could be obtained after being eluted by DEAE-Sepharose. Structural analysis indicated that NPs was formed by 1,4-β-linked xylp backbone. Monosaccharide composition and methylation analysis suggested that glucose, arabinose, galactose and rhamnose constituted side chains with the molar ratio of 1.22:1.79:1.89:4.46 with the glycosidic linkages of →4)-Glc-(1→, →3,5)-Ara-(1→, →4)-Gla-(1→, →4)-Rha-(1 → and → 2,4)-Rha-(1→. Antioxidant assays demonstrated that NPs exhibited relatively high activity in a dose-dependent manner with the highest 85.9% DPPH and 99.78% ABTS free radical scavenging rate when the concentration was 4.0 and 3.0 mg/mL, respectively. Moreover, NPs exhibited obvious growth inhibitory against E. coli, S. aureus and B. subtilis when the NPs concentration was in range of 0.50-50.0 mg/mL. Therefore, we concluded that NPs from bamboo leaves could be used as a potential and natural bacteriostat and antioxidant.
