Singh B, Kaur A
Department of Microbiology, Guru Nanak Dev University, Amritsar, India.
J Appl Microbiol. 2016 Feb;120(2):301-11. doi: 10.1111/jam.12998.
To exploit the potential of endophytic fungi for pharmaceutically important antidiabetic alpha glycosidase inhibitors.
Thirty six endophytic fungi were isolated from Acacia nilotica and screened for the production of alpha amylase and glucosidase inhibitors. Inhibitory activity against both alpha amylase (81%) and alpha glucosidase (80%) was exhibited in an isolate, identified to be Aspergillus awamori. Purification of the inhibitor was carried out on Sephadex LH-20 column and semi prep HPLC. The inhibitor was characterized to be proteinaceous in nature with an approximate molecular mass of 22 kDa. UHPLC amino acid analysis indicated the presence of amino acids serine, threonine, tyrosine and valine in the peptide. The purified inhibitor exhibited mixed type of inhibition against alpha amylase and alpha glucosidase with IC50 values of 3·75 and 5·625 μg ml(-1) respectively. The inhibitor was stable over a wide range of pH and temperature. Optimization of process parameters to increase the yield of the inhibitor was undertaken using one factor at a time approach as well as RSM statistical analysis. The interaction of dextrose and proteose peptone for the test organism was significant with first order effect of pH. Increase of 13% was obtained in the inhibitory activity after optimization of process parameters. Mutagenicity testing by Ames test revealed nonmutagenic nature of the peptide.
Endophytic A. awamori is capable of producing a peptide with alpha glycosidase inhibitory activity.
The inhibitor obtained in this study possesses dual (alpha glucosidase and alpha amylase) inhibitory activity, low IC50 values, is highly stable under extreme conditions of pH and temperature, and is nonmutagenic in nature. By virtue of its properties it can be commercially produced and exploited for better management of diabetes.
开发内生真菌在具有重要药学意义的抗糖尿病α-糖苷酶抑制剂方面的潜力。
从阿拉伯胶树中分离出36株内生真菌，并筛选其α-淀粉酶和葡萄糖苷酶抑制剂的产生情况。一株被鉴定为泡盛曲霉的分离物对α-淀粉酶（81%）和α-葡萄糖苷酶（80%）均表现出抑制活性。通过葡聚糖凝胶LH-20柱和半制备高效液相色谱对抑制剂进行纯化。该抑制剂经鉴定为蛋白质性质，近似分子量为22 kDa。超高效液相色谱氨基酸分析表明该肽中存在丝氨酸、苏氨酸、酪氨酸和缬氨酸。纯化后的抑制剂对α-淀粉酶和α-葡萄糖苷酶表现出混合型抑制作用，IC50值分别为3.75和5.625 μg/ml。该抑制剂在较宽的pH和温度范围内稳定。采用一次只改变一个因素的方法以及响应曲面法统计分析对工艺参数进行优化以提高抑制剂产量。葡萄糖和蛋白胨对受试微生物的相互作用具有显著性，且pH有一级效应。工艺参数优化后抑制活性提高了13%。通过艾姆斯试验进行的致突变性测试表明该肽无致突变性。
内生泡盛曲霉能够产生具有α-糖苷酶抑制活性的肽。
本研究中获得的抑制剂具有双重（α-葡萄糖苷酶和α-淀粉酶）抑制活性、低IC50值，在极端pH和温度条件下高度稳定，且本质上无致突变性。凭借其特性，它可进行商业化生产并用于更好地管理糖尿病。
