In vitro and in vivo hypoglycemic effects of brown algal fucoidans.

The inhibition of α-glucosidase is an effective therapeutic approach for type 2 diabetes mellitus that involves decreasing postprandial hyperglycemia. In the present study, the α-glucosidase and α-amylase inhibitory effects of 11 fucoidans extracted from different brown seaweeds were evaluated. Although no significant α-amylase inhibition was observed, fucoidan from Fucus vesiculosus (FvF) showed the highest α-glucosidase inhibitory activity, with an IC50 value of 67.9 μg/mL. In addition, FvF at a concentration of 200 μg/mL displayed very mild cytotoxicity to IEC-6 cells as indicated by the MTT assay. An in vivo study indicated that FvF decreased the fasting blood glucose and hemoglobin A1c (HbA1c) levels of db/db mice, with minimal effect on their weight. Therefore, our present in vitro and in vivo studies demonstrated that FvF could be a promising α-glucosidase inhibitor for the treatment of type 2 diabetes mellitus.