阿勒泰黄芪提取物对蛋白酪氨酸磷酸酯酶1B的抑制作用

Inhibitory Effect of Extracts from Astragalus altaicus Bgeon Protein Tyrosine Phosphatase 1B Activity

本文探讨了阿勒泰黄芪不同提取物对蛋白酪氨酸磷酸酯酶1B(PTP1B)的抑制作用。采用分光光度法测定了提取物中的黄酮和皂苷含量;通过体外酶促动力学方法检测了不同提取物对PTP1B的影响,并确定了抑制类型;并采用氧化酶法检测了阿勒泰黄芪提取物对细胞利用葡萄糖能力的作用。结果表明,阿勒泰黄芪8种提取物(E1～8)中黄酮含量分别为5.09、10.46、3.58、3.23、53.91、21.77、5.76和7.49 mg/mL,其中E1、E2、E6、E7、E8皂苷含量分别为16.53、27.45、21.90、10.21和8.96 mg/mL;各提取物对PTP1B活性均表现出抑制作用,其中E1、E2、E7、E8的IC50分别为34.8、4.7、7.35和7.15μg/mL,E1、E7和E8是竞争性抑制,E2是混合型竞争性抑制。E1、E2、E5、E7和E8较明显的提高了CHO-K1细胞对葡萄糖的利用。提示皂苷可能是阿勒泰黄芪抑制PTP1B活性的主要物质,通过PTP1B途径有效了提高细胞利用葡萄糖的能力。本研究为阿勒泰黄芪开发为防治糖尿病及改善胰岛素抵抗的药物或保健品提供实验依据。

This paper aimed to explore inhibitory effectof extracts from Astragalus altaicus Bge on the protein tyrosine phosphataselB. The contents of flavonoids and saponins of eight extracts（ E1-8 ） obtained from A. altaicus were measured by spectrophotometric assay. The results indicated that contents of flavanoids of El-8 were 5.09,10.46,3.58,3.23,53. 91,21.77,5.76 and 7.49 ,respectively,and those of saponins of E1 ,E2 ,E6 ,E7 and E8 were 34.8,4.7,7.35 and 7.15 p.g/mL, respectively. The in vitro PTP1 B inhibitor screening system was applied to detect the inhibitory ability and the results indicated that ICso of El, E2, E7, and E8 were 34.8,4.7,7.35and 7.15 μg/mL, respectively. The enzyme kinetic studies revealed non-competitive type of inhibition of El, E7, E8 and mixed competitive type of inhibition of E2. In addition,E1 ,E2,ES,E7 and E8 obviously enhanced the rate of glucose intake in CHO cells,but E3,E4 and E6 were not. Therefore saponins might be major active substances in A. altaicus, which could increase the rate of glucose intake in CHO cells by PTP1B pathway. These findings might provide experimental support for further exploration and utilization of A. altaicus.