Preliminary characterization, antioxidant and α-glucosidase inhibitory activities of polysaccharides from Mallotus furetianus

A purified polysaccharide, designated as MFP-2A, was isolated from Mallotus furetianus (Bail) Muell Arg. The primary structure characteristics were determined by HPGPC, HPLC, FT-IR, methylation analysis, NMR, SEM and AFM. The results showed that MFP-2A was a homogeneous heteropolysaccharide with an average molecular weight of 25.96 KDa. The monosaccharide composition was consisted of mannose, galactose, arabinose, galacturonic acid and glucose with a molar ratio of 3.05:2.84:1.84:0.86:1.41. In addition, methylation and NMR analysis revealed that the main glycosidic bonds of MFP-2A were comprised of 1,4,6-linked-β-d-Galp, 1,3,6-linked-β-d-Manp, 1,5-linked-α-l-Araf, 1-linked-α-l-Araf, 1,4-linked-α-d-GalAp and 1,4-linked-α-d-Glcp residues. Moreover, MFP-2A also exhibited significant free radical scavenging ability and α-glucosidase inhibitory activities in vitro. Overall, these results demonstrated that MFP-2A from Mallotus furetianus (Bail) Muell Arg could serve as a potential anti-diabetic and functional food.