3.2. a-Glucosidase and a-amylase inhibitory
activities
In order to investigate the inhibitory effect of S. surattensis
extract, an in vitro a-glucosidase inhibition test was performed.
Although a-glucosidase isolated from yeast is
extensively used as a screening material for a-glucosidase
inhibitors, the results did not always agree with those obtained
in mammals. The half maximal inhibitory concentration
(IC50) values of maltase and sucrase inhibitory
activities were 209.15 and 366.44 mg/mL, respectively. The
results in Figs. 1 and 2 show that EESS exhibited strong
activity in a dose-dependent manner and is thus inferred to
be an effective a-glucosidase inhibitor. In this study, EESS
exhibited strong inhibitory activity against a-glucosidase
and a-amylase, which is comparable with positive controls
of acarbose and nojirimycin, respectively. In addition, EESS
inhibited the activity of a-amylase with IC50 of 123.95 mg/
mL, the result of which is shown in Fig. 3. However, EESS
showed weak a-glucosidase and a-amylase inhibitory
activities compared with acarbose and nojirimycin,
respectively. These results confirm that EESS have
a-glucosidase and a-amylase inhibitory properties.