School of Biomedical Sciences, Ulster University, Coleraine, BT52 1SA, Co. Londonderry, Northern Ireland, United Kingdom.
Biosci Rep. 2021 Jan 29;41(1). doi: 10.1042/BSR20203824.
The present study investigated the effects of hot water extracts of 22 medicinal plants used traditionally to treat diabetes on Dipeptidyl peptidase-IV (DPP-IV) activity both in vitro and in vivo in high-fat fed (HFF) obese-diabetic rats. Fluorometric assay was employed to determine the DPP-IV activity. For in vivo studies, HFF obese-diabetic rats were fasted for 6 h and blood was sampled at different times before and after the oral administration of the glucose alone (18 mmol/kg body weight) or with either of the four most active plant extracts (250 mg/5 ml/kg, body weight) or established DPP-IV inhibitors (10 μmol/5 ml/kg). DPP-IV inhibitors: sitagliptin, vildagliptin and diprotin A, decreased enzyme activity by a maximum of 95-99% (P<0.001). Among the 22 natural anti-diabetic plants tested, AnogeissusLatifolia exhibited the most significant (P<0.001) inhibitory activity (96 ± 1%) with IC50 and IC25 values of 754 and 590 μg/ml. Maximum inhibitory effects of other extracts: Aegle marmelos, Mangifera indica, Chloropsis cochinchinensis, Trigonella foenum-graecum and Azadirachta indica were (44 ±7%; 38 ± 4%; 31±1%; 28±2%; 27±2%, respectively). A maximum of 45% inhibition was observed with >25 μM concentrations of selected phytochemicals (rutin). A.latifolia, A. marmelos, T. foenum-graecum and M. indica extracts improved glucose tolerance, insulin release, reduced DPP-IV activity and increased circulating active GLP-1 in HFF obese-diabetic rats (P<0.05-0.001). These results suggest that ingestion of selected natural anti-diabetic plants, in particular A. latifolia, A. marmelos, T. foenum-graecum and M. indica can substantially inhibit DPP-IV and improve glucose homeostasis, thereby providing a useful therapeutic approach for the treatment of T2DM.
本研究旨在探讨 22 种传统用于治疗糖尿病的药用植物的热水提取物对高脂喂养（HFF）肥胖型糖尿病大鼠体内外二肽基肽酶-IV（DPP-IV）活性的影响。采用荧光测定法测定 DPP-IV 活性。在体内研究中，HFF 肥胖型糖尿病大鼠禁食 6 小时，在单独给予葡萄糖（18mmol/kg 体重）或四种最具活性的植物提取物（250mg/5ml/kg，体重）或已建立的 DPP-IV 抑制剂（10μmol/5ml/kg）前后不同时间采血。DPP-IV 抑制剂：西他列汀、维格列汀和二肽基肽酶 A，可使酶活性最大降低 95-99%（P<0.001）。在所测试的 22 种天然抗糖尿病植物中，AnogeissusLatifolia 表现出最显著的抑制活性（P<0.001）（96±1%），IC50 和 IC25 值分别为 754 和 590μg/ml。其他提取物的最大抑制作用：Aegle marmelos、Mangifera indica、Chloropsis cochinchinensis、Trigonella foenum-graecum 和 Azadirachta indica 分别为（44±7%；38±4%；31±1%；28±2%；27±2%）。选定的植物化学物质（芦丁）浓度>25μM 时，观察到最大 45%的抑制作用。A.latifolia、A. marmelos、T. foenum-graecum 和 M. indica 提取物改善了 HFF 肥胖型糖尿病大鼠的葡萄糖耐量、胰岛素释放、降低了 DPP-IV 活性并增加了循环中活性 GLP-1（P<0.05-0.001）。这些结果表明，摄入选定的天然抗糖尿病植物，特别是 A. latifolia、A. marmelos、T. foenum-graecum 和 M. indica，可显著抑制 DPP-IV 并改善葡萄糖稳态，从而为治疗 T2DM 提供了一种有用的治疗方法。
