Application of Response Surface Methodology for Optimizing the Extraction Conditions of Total Saponins from Polyscias fruticosa (L.) Harms Planted in Southern Vietnam

Aims: This study aimed to optimizing the extraction conditions for total saponins from Polyscias fruticosa using response surface methodology coupled with Box-Behnken design (RSM-BBD).

Methodology: The optimization process for extraction of saponins from the roots of Polyscias fruticosa was involved in three parameters including extraction temperature, time, and solvent-to-sample ratio. The three levels of independent variables were identified by screening test. The response surface methodology conjugated with Box-Behnken design was then applied to investigate the affinities between the extraction variables and experimental response (extraction yield) which was expressed in terms of mg oleanolic acid equivalents (OAE) per gram of plant extract.

Results: Based on the analysis of all integrated data, the optimal extraction conditions were predicted to be temperature of 60.91°C, extraction time of 4.57 hours and solvent/sample ratio of 10.3:1 (mL/g). The highest total saponins content value predicted by response surface methodology was 37.18 mg OAE/g of plant extract which was in close agreement with the corresponding experimental value of total saponins content (37.42 ± 0.26 mg OAE per g of plant extract) (n = 3, p < 0.05).

Conclusion: The strong correlation between the real and the predicted data indicated that the response model was adequate to reflect the expected optimization.