Hung Tran Manh, Hoang Duc Manh, Kim Jin Cheol, Jang Han-Su, Ahn Jong Seog, Min Byung-Sun
College of Pharmacy, Catholic University of Daegu, Gyeongsan 712-702, Republic of Korea.
J Ethnopharmacol. 2009 Jul 15;124(2):240-5. doi: 10.1016/j.jep.2009.04.027. Epub 2009 May 3.
Gynostemma pentaphyllum (Thunb.) tea was used in Vietnamese folk medicine as anti-diabetic agent.
This study was aimed to investigate the inhibitory activities of fractions and constituents isolated from Gynostemma pentaphyllum on protein tyrosine phosphatase 1B (PTP1B) since it has been proposed as a treatment therapy for type 2 diabetes and obesity.
The 70% EtOH extract, CHCl3 fraction, EtOAc fraction, BuOH fraction, and seven isolated dammarane triterpenes were evaluated for their inhibitory activity in protein phosphatase enzymes (PTP1B and VHR).
CHCl3-soluble fraction showed a dose-dependent inhibitory activity of the PTP1B enzyme with the IC50 value of 30.5 microg/mL. Among seven tested compounds, compounds 6 showed the most potent PTP1B inhibitory activity with IC50 value of 5.3+/-0.4 microM compared to a range 15.7-28.5 microM for the other six compounds. The inhibition mode of 6 was competitive toward p-NPP with a K(i) value of 2.8 microM.
These study results suggested that the PTP1B inhibitory activity of these dammaranes may enable this plant to play an important role in the treatment of diabetes.
绞股蓝茶在越南民间医学中被用作抗糖尿病药物。
本研究旨在研究从绞股蓝中分离得到的各馏分和成分对蛋白酪氨酸磷酸酶1B（PTP1B）的抑制活性，因为PTP1B已被提议作为2型糖尿病和肥胖症的一种治疗方法。
对70%乙醇提取物、氯仿馏分、乙酸乙酯馏分、正丁醇馏分以及七种分离得到的达玛烷三萜进行蛋白磷酸酶（PTP1B和VHR）抑制活性评估。
氯仿可溶馏分对PTP1B酶表现出剂量依赖性抑制活性，IC50值为30.5微克/毫升。在七种测试化合物中，化合物6表现出最强的PTP1B抑制活性，IC50值为5.3±0.4微摩尔，而其他六种化合物的IC50值在15.7 - 28.5微摩尔范围内。化合物6对p - NPP的抑制模式为竞争性抑制，K(i)值为2.8微摩尔。
这些研究结果表明，这些达玛烷的PTP1B抑制活性可能使该植物在糖尿病治疗中发挥重要作用。
