蔓荆子化学成分及主要单体降血糖活性研究

Study on chemical constituents from Vitex trifolia and the hypoglycemic activity of main monomers

目的分离蔓荆子三氯甲烷部位的化学成分,并测试重点化合物体外降血糖活性。方法采用硅胶柱层析、ODS柱色谱、Sephadex LH-20柱色谱及重结晶等方法对蔓荆子醇提物的三氯甲烷部位进行分离纯化,并通过理化性质与核磁、质谱等光谱分析方法鉴定化合物的结构;建立胰岛素抵抗HepG2细胞模型,检测化合物降血糖活性;与降血糖靶点分子对接评估和预测结合力。结果分离鉴定出7个单体化合物,分别为β-谷甾醇(1)、5-羟基-3,7,3’,4’-四甲氧基黄酮(2)、10-甲基二十烷(3)、香草酸(4)、对羟基苯甲酸(5)、原儿茶酸(6)、3β-羟基-5α,8α-过氧化麦角甾-6,22-二烯(7);细胞实验表明化合物7可较好地改善造模后HepG2细胞胰岛素抵抗;14种降血糖靶点蛋白均可与过氧麦角甾醇结合,其中与靶点蛋白iNOS、GLUT4结合能力最强,通过抑制iNOS可减少胰岛细胞凋亡,与GLUT4结合可促进葡萄糖的摄取和利用。结论化合物2、3为首次从该植物中分离得到;降血糖活性筛选和靶点预测为蔓荆子降血糖活性化合物过氧麦角甾醇的应用研究与开发提供了实验基础。

Objective To isolate the chemical constituents from the chloroform extract of V.trifolia and study the hypoglycemic activity of the compositions.Methods The compositions of chloroform fraction were isolated by gel chromatography,ODS column chromatography,Sephadex LH-20 and recrystallization.The structures were identified according to the data of MS,NMR and physicochemical characters.Insulin resistant model of HepG2 cells was established to detect the hypoglycemic effect of the compositions.Results Seven compounds were isolated and identified from the chloroform extract of V.trifolia.Respectively as:β-sitosterol(1),5-hydroxy-3,7,3’,4’-tetramethoxy flavone(2),10-methyl eicosane(3),vanillic acid(4),p-hydroxybenzoic acid(5),protocatechuic acid(6),3β-hydroxy-5α,8α-ergosteroid-6,22-diene(peroxy ergosterol)(7).Compound 7 could improve the insulin resistance of HepG2 cells.All 14 hypoglycemic target proteins could bind to peroxy ergosterol,among which the binding ability with iNOS and GLUT4 target proteins were the strongest.Inhibition of iNOS could reduce apoptosis of islet cells,and binding with GLUT4 could promote the uptake and utilization of glucose.Conclusion Compounds 2 and 3 have been isolated from this plant for the first time.The screening of hypoglycemic activity and target prediction provide experimental basis for the application research and development of peroxy ergosterol.