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

摘要： α-淀粉酶抑制剂属于糖苷水解酶抑制剂中的一种,能有效地抑制肠道内唾液及胰淀粉酶的活性,阻碍食物中碳水化合物的水解和消化,减少糖分的摄取,降低血糖和血脂含量水平,使食后不产生高血糖症。本实验利用快速灵敏的比色法,对从几种药用植物体内分离得到的70株内生放线菌菌丝提取物和发酵液的α-淀粉酶抑制活性进行了检测,得出:具有产胞外α-淀粉酶抑制剂活性的菌株19株,抑制率达70%以上的有6株;产胞内α-淀粉酶抑制剂活性的菌株16株,其中抑制率达70%以上的有3株;既能产胞内α-淀粉酶抑制剂又能产胞外α-淀粉酶抑制剂的菌株7株。从菌株WS19发酵液中分离获得了α-淀粉酶抑制剂WSI19,对α-淀粉酶和α-麦芽糖酶均有显著抑制,且对麦芽糖酶的抑制性比同剂量的奥恬苹还强11.2 倍。经小鼠糖耐量实验,证实WSI19 对餐后高血糖有明显改善。总体上看,药用植物内生放线菌具有很大的产α-淀粉酶抑制剂潜力,可进一步为开发糖尿病药物。

关键词: α-淀粉酶抑制剂, 内生放线菌, 活性, 筛选