Abstract
A screening method for α- and β-D-glucosidase inhibitors was developed by using agar plates. An enzyme agar plate containing either α- or β-D-glucosidase was used in combination with a substrate agar plate containing p-nitrophenyl α- or β-D-glucopyranoside. Paper disks impregnated with algal extracts were placed on the enzyme agar plate, then preincubated for 2.5 h at 25°C. The substrate agar was layered on the enzyme agar. Inhibitory zones appeared colorless in the yellow background of p-nitrophenol. Extracts of algae collected in southern Hokkaido were screened for α- and β-D-glucosidase inhibitors by the proposed agar plate method. Among nine algal species examined, seven species inhibited α-D-glucosidase, whereas five species inhibited β-D-glucosidase.
