Evaluation of the extraction process of Arenaria hispanica L. using response surface methodology on amounts of total phenolic content, total flavonoid content and the antioxidant activity

The selection of appropriate conditions for increasing the extraction efficiency is important. The response surface method (RSM) is a statistical and mathematical technique which it can be used to examine the dependence between the responses with variables in a process and also determine the optimal conditions. In this study, the experimental design of General full factorial (GFF) was used by Minitab 17 software. The variables were time (30, 60 and 90 min), solvent (water, methanol and n-hexane) and method (maceration and ultrasound-assisted extraction). The main effects and also interaction terms were investigated on amounts of total phenolic content (TPC), total flavonoid content (TFC) and the antioxidant activity (according to DPPH, FRAP, IC50 and BCB) of extract of Arenaria hispanica L.. A multiple regression, first degree model was used to express the responses. An analysis of variance (ANOVA) with 95% confidence level was then carried out for each response (TPC, TFC, FRAP, IC50 and BCB) in order to test the model significance and suitability. In optimum conditions, the maceration method was optimum method for TPC, FRAP and BCB, while for TFC was ultrasound-assisted extraction. Water was optimal solvent for TPC, FRAP and BCB, but methanol was obtained as the best solvent for TFC and IC50. Also, the extraction time of TPC was 60 min and for TFC, IC50, FRAP and BCB obtained 30 min. The mounts of TPC, TFC, IC50, FRAP and BCB in the optimum conditions obtained 173.93 +/- 0.50 (mg GAE/g extract), 184.27 +/- 4.04 (mg QC/g extract), 0.69 +/- 0.03 (mg/mL), 734.80 +/- 2.02 (mmol Fe2+/g exctract) and 21.23 +/- 0.22; respectively.