Different Proportions of Huangqi (Radix Astragali Mongolici) and Honghua (Flos Carthami) Injection on α-Glucosidase and α-Amylase Activities

Objective. To study the effect of different proportions of Huangqi (Radix Astragali Mongolici) and Honghua (Flos Carthami) injection on α-glucosidase and α-amylase activity simultaneously. Methods. The injections were prepared according to the standards of the China Food and Drug Administration. The assay for potential α-glucosidase inhibitors was based on the hydrolysis of 4-methylumbelliferyl-α-D-glucopyranoside (4-MUG). The α-amylase EnzChek assay kit was used to determine potential α-amylase inhibitors. Acarbose was the positive control. Results. The half maximal (50%) inhibitory concentration (IC(50)) of acarbose against α-glucosidase and α-amylase was (1.8 ± 0.4) μg/mL and (227 ± 32) μg/mL, respectively. Honghua showed significant inhibition of α-glucosidase activity compared with Huangqi (P < 0.01). Honghua inhibited α-amylase activity, but Huangqi did not. IC(50)s for α-glucosidase inhibition by mixtures at 10 : 1, 5 : 1, and 2 : 1 were significantly lower than those at the 20 : 1 mixture (P < 0.01). α-Amylase inhibition by the 2 : 1 mixture was significantly higher than that by the 20 : 1, 10 : 1, and 5 : 1 mixtures at 500 μg/mL and 1000 μg/mL (P < 0.01), with 5 : 1 significantly higher than 20 : 1 and 10 : 1 at 1000 μg/mL (P < 0.01). Conclusion. Honghua significantly inhibited α-glucosidase activity compared with Huangqi (P < 0.01). For simultaneous inhibition of α-glucosidase and α-amylase activities, the mixtures at 2 : 1 and 5 : 1 exhibited significant effects compared with those at 20 : 1 (P < 0.01).