Department of Physiology, University of Manitoba, Winnipeg, MB, Canada R3E3P4.
J Ethnopharmacol. 2012 Jul 13;142(2):488-95. doi: 10.1016/j.jep.2012.05.024. Epub 2012 May 23.
Several Asian plants are known for their anti-diabetic properties and produce alkaloids and flavonoids that may stimulate insulin secretion.
Using Vietnamese plants (Nelumbo nucifera, Gynostemma pentaphyllum, Smilax glabra, and Stemona tuberosa), we extracted two alkaloids (neotuberostemonine, nuciferine) and four flavonoids (astilbin, engeletin, smitilbin, and 3,5,3'-trihydroxy-7,4'-dimethoxyflavone), and studied their insulin stimulatory effects.
Nuciferine, extracted from Nelumbo nucifera, stimulated both phases of insulin secretion in isolated islets, whereas the other compounds had no effect. The effect of nuciferine was totally abolished by diazoxide and nimodipine, and diminished by protein kinase A and protein kinase C inhibition. Nuciferine and potassium had additive effects on insulin secretion. Nuciferine also stimulated insulin secretion in INS-1E cells at both 3.3 and 16.7 mM glucose concentrations. Compared with glibenclamide, nuciferine had a stronger effect on insulin secretion and less beta-cell toxicity. However, nuciferine did not compete with glibenclamide for binding to the sulfonylurea receptor.
Among several compounds extracted from anti-diabetic plants, nuciferine was found to stimulate insulin secretion by closing potassium-adenosine triphosphate channels, explaining anti-diabetic effects of Nelumbo nucifera.
几种亚洲植物因其抗糖尿病特性而闻名，它们产生的生物碱和类黄酮可能刺激胰岛素分泌。
使用越南植物（荷花、绞股蓝、菝葜和直立百部），我们提取了两种生物碱（新藤碱、荷叶碱）和四种类黄酮（Astilbin、Engelitin、Smitilbin 和 3,5,3'-三羟基-7,4'-二甲氧基黄酮），并研究了它们的胰岛素刺激作用。
荷叶碱从荷花中提取，刺激分离胰岛的胰岛素分泌的两个阶段，而其他化合物则没有作用。荷叶碱的作用被二氮嗪和尼莫地平完全阻断，并被蛋白激酶 A 和蛋白激酶 C 抑制所减弱。荷叶碱和钾对胰岛素分泌有相加作用。荷叶碱也能刺激 INS-1E 细胞在 3.3 和 16.7mM 葡萄糖浓度下的胰岛素分泌。与格列本脲相比，荷叶碱对胰岛素分泌的作用更强，对β细胞的毒性更小。然而，荷叶碱与磺酰脲受体的结合不与格列本脲竞争。
在几种从抗糖尿病植物中提取的化合物中，荷叶碱被发现通过关闭钾-三磷酸腺苷通道刺激胰岛素分泌，解释了荷花的抗糖尿病作用。
