Optimization of extraction process and activity of total alkaloids from Astragalus adsurgens using response surface methodology

Astragalus adsurgens is an excellent forage containing alkaloids. This study employed Box-Behnken response surface methodology to optimize the extraction process of total alkaloids from A.adsurgens by investigating three main factors: ethanol concentration, liquid-to-solid ratio, and extraction time.Antioxidant and antibacterial activity were also determined. Results indicated that the optimal extraction conditions for total alkaloids were an ethanol concentration of 80.93%, a liquid-to-material ratio of 1.00 ꞉ 21.36, and a 2.75-h extraction time. The predicted maximum yield is 0.14%. Total alkaloids in A. adsurgens had strong antioxidant capacity. As the concentration of A. adsurgens total alkaloids increased, the clearance rate gradually increased, and the total antioxidant capacity gradually strengthened before decreasing. The minimum inhibitory concentrations for Staphylococcus aureus and Escherichia coli were 100 and 50 mg·mL⁻¹, respectively. The results of this study have important significance for the development and utilization of total alkaloids of A.adsurgens and the promotion of resistant culture.