Twenty-six samples of indigenous medicinal plants were collected in Dak Lak Province of Vietnam and evaluated for α-amylase inhibitory activity. Of these samples, trunk bark extract from Euonymus laxiflorus Champ. (ELC extract) showed the greatest α-amylase inhibitory activity with the smallest 50 % inhibitory concentration (IC50) of 6.6 ± 0.6 µg/mL against porcine pancreatic α-amylase. This extract possessed strong inhibitory activity against human saliva α-amylase and slightly lower activity against Bacillus subtilis α-amylase, with IC50 values of 4.2 ± 0.2 and 27.8 ± 1.8 µg/mL, respectively. ELC extract was found to be strongly thermostable, retaining 72–100 % relative activity even after heating at 100 °C for 5 min to 2 h. This extract was also stable at various pH values. These results suggest that ELC extract may be a good candidate for treatment of non-insulin-dependent diabetes mellitus (NIDDM) and obesity.
Research on Chemical Intermediates 43(1), p.259–269