Fucoidan--a α-D-glucosidase inhibitor from Sargassum wightii with relevance to type 2 diabetes mellitus therapy.

The present study was conducted to screen the α-d-glucosidase inhibitory activity of fucoidan extracted from Sargassum wightii collected at Mandapam coastal area, Tamil Nadu, India. Fucoidan was extracted from the sporophyll of S. wightii using ethanol, acetone and CaCl2 precipitation. The average yield was 1.8 ± 0.16% and the extracted fucoidan was found to contain 53 ± 0.52% of fucose and 36 ± 0.60% of sulphate. FT-IR, NMR and in vitro α-d-glucosidase activity of purified fucoidan were performed. Fucoidan at the concentration of 31.25, 62.5, 125 and 250 μg exhibited 19, 31, 38 and 71% inhibition against α-d-glucosidase respectively in a dose dependent manner. The IC50 value against α-D-glucosidase of fucoidan is found to be 132.9 μg which is more effective than that of acarbose (1mg). The diverse biological activities of Fucoidan include anticancer, anti inflammatory and antimicrobial but the α-d-glucosidase inhibitory activity of native fucoidan from S. wightii for type 2 diabetes therapy is first of its kind.