关键词: α-淀粉酶抑制剂, 内生放线菌, 活性, 筛选

Abstract: α-amylase inhibitor is a kind of glycosidase inhibitors. It can inhibit the activity of ptyalase and amylopsin,prevent the hydrolysis and digestion of carbohydrates,reduce the intake of sugar,so that depress postprandial blood glucose level. In this paper,the α-amylase inhibitory activity of the mycelium extracts and broth of 70 endophytic actinomycetes associated with medicinal plants was detected with rapid and sensitive colorimetry. The results showed that,there are 19 strains having the ability to produce extracellular α-amylase inhibitor,6 of them having more than 70% inhibion rate; there are 16 strains having the ability to produce intracellular α-amylase inhibitor,3 of them having more than 70% inhibion rate; there are 7 strains having the ability to produce both extracellular and intracellular α-amylase inhibitor. The α-amylase inhibitor WSI19 was isolated and purified from the strain WS19,it could efficaciously inhibit α-amylase and α-maltase,and the inhibition of maltase is stronger than the same dose of miglitol 11.2 times. The glucose tolerance test in mice confirmed that WSI19 could significantly depress blood glucose levels. In a word,endophytic actinomycetes from medical plants have a better potential to produce α-amylase inhibitor,and could be developed to a possible therapeutic agent for diabetes.

Key words: α-amylase inhibitor, endophytic actinomycetes, activity, screening