Abstract:

Objective: To develop a colorimetric method for determining the content of total saponins in Opuntia Milpa Alta and optimize the ultrasonic-assisted ethanol extraction of total saponins from the plant. Methods: For determining the content of total saponins in Opuntia Milpa Alta, a standard curve of oleanolic acid was plotted. Optimization of the ultrasonic-assisted ethanol extraction of total saponins was performed using single factor and orthogonal array design methods. Results: The relative standard deviations of precision and stability of the method were 1.13% and 0.52% respectively, and the average spike recovery was 99.17%, with a RSD of 1.86%. The optimum ultrasonic extraction conditions were found to be: ethanol concentration 80%, solid-to-liquid ratio 1:15, extraction temperature 70 ℃, ultrasonic power 100 W and extraction duration 70 minutes. Conclusion: The developed method for total saponin determination is simple, feasible and accurate. The optimized extraction process is efficient, economical and quick, thereby being easy to popularize.

Key words: total saponins, Opuntia Milpa Alta, colorimetry, mass fraction, ultrasonic extraction