The structure, conformation, and hypoglycemic activity of a novel heteropolysaccharide from the blackberry fruit

A novel heteropolysaccharide fraction (BBP-24-3) with a relative molecular weight of 145.1 kDa was isolated from blackberry fruits. The BBP-24-3 was mainly composed of arabinose, glucose, and galacturonic acid with a ratio of 5.30 : 3.60 : 91.10 mol%. Structural analysis showed that BBP-24-3 possessed a 1,6-linked beta-d-Glcp, 1, 2, 3, 5 linked alpha-l-Araf, and 1, 4 linked alpha-d-GalpA backbone with branches substituted at the C-2 and C-5 positions of arabinose units, which included 1, 2, 3, 4 linked beta-d-Glcp and T-linked beta-d-GalpA. The conformation analysis indicated that BBP-24-3 exhibited a solid spherical structure with a uniform distribution in 0.1 M NaCl solution. The BBP-24-3 exhibited excellent alpha-glucosidase inhibitory activity with an IC50 value of 3.70 mg mL(-1), which was due to the structural change, including alpha-helix and random coil of alpha-glucosidase caused by BBP-24-3. The current work suggests the potential utilization of BBP-24-3 as an alpha-glucosidase inhibitor in healthy food for reducing the postprandial blood glucose level.

Automated summary

A novel heteropolysaccharide fraction (BBP-24-3) with a relative molecular weight of 145.1 kDa isolated from blackberry fruits showed excellent alpha-glucosidase inhibitory activity. This potential utilization of BBP-24-3 as an alpha-glucosidase inhibitor in healthy food for reducing the postprandial blood glucose level was suggested by the current study.