Abstract: This paper aimed to explore inhibitory effectof extracts from Astragalus altaicus Bge on the protein tyrosine phosphatase1B. 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 flavonoids of E1-8 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 μg/mL, respectively. The in vitro PTP1B inhibitor screening system was applied to detect the inhibitory ability and the results indicated that IC50 of E1, 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 E1, E7, E8 and mixed competitive type of inhibition of E2. In addition, E1, E2, E5, 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.

Key words: Astragalus altaicus Bge, 2 type diabetes, protein tyrosine phosphatase 1B, inhibition