This 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 hours and blood was sampled at different times before and after the oral administration of the glucose alone (18mmol/kg body weight) or with either of the four most active plant extracts (250mg/5ml/kg, body weight) or established DPP-IV inhibitors (10µmol/5ml/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, A. Latifolia exhibited the most significant (P<0.001) inhibitory activity (96 ± 1%) with IC50 and IC25 values of 754μg/ml and 590μg/ml. Maximum inhibitory effects of other extracts: A. marmelos, M. indica, C. colchinchinensis, T. foenum-graecum and A. indica were (44 ±7%; 38 ± 4%; 31±1%; 28±2%; 27±2%, respectively). A maximum of 45% inhibition was observed with >25µM 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.

中文翻译：

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22 种传统抗糖尿病药用植物对高脂喂养肥胖糖尿病大鼠 DPP-IV 酶活性和葡萄糖稳态的影响。

本研究调查了传统上用于治疗糖尿病的 22 种药用植物的热水提取物对高脂肪喂养 (HFF) 肥胖糖尿病大鼠的体外和体内二肽基肽酶-IV (DPP-IV) 活性的影响。采用荧光测定法来确定 DPP-IV 活性。对于体内研究，HFF 肥胖-糖尿病大鼠禁食 6 小时，并在单独口服葡萄糖（18mmol/kg 体重）或四种最活跃的植物提取物之前和之后的不同时间采集血液样本（ 250mg/5ml/kg，体重）或已建立的 DPP-IV 抑制剂（10μmol/5ml/kg）。DPP-IV 抑制剂：西格列汀、维格列汀和双蛋白 A，使酶活性降低最多 95-99%（P<0.001）。在测试的 22 种天然抗糖尿病植物中，阔叶 A. Latifolia 表现最显着（P < 0. 001) 抑制活性 (96 ± 1%)，IC50 和 IC25 值为 754μg/ml 和 590μg/ml。其他提取物的最大抑制作用：马铃薯、M. indica、C. colchinchinensis、T. foenum-graecum 和 A. indica 分别为 (44 ±7%; 38 ± 4%; 31±1%; 28±2%; 27±2%）。使用 >25µM 浓度的选定植物化学物质（芦丁）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 - 糖尿病大鼠的葡萄糖耐量、胰岛素释放、降低 DPP-IV 活性和增加循环活性 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，特别是阔叶 A.、A. marmelos、T. foenum-graecum 和 M. indica 可以显着抑制 DPP-IV 并改善葡萄糖稳态，