Optimization of ultrasound-assisted extraction of phenolic compounds from Justicia spicigera Schltdl. by response surface methodology

Abstract

The interest in the study of polyphenols has grown considerably in recent years due to its high capacity to scavenge free radicals associated with various diseases. For this reason, the aim of this work was to obtain and characterize phenolic compounds from Justicia spicigera Schltdl by ultrasound-assisted extraction. The extracts were characterized in terms of the total phenolic content (Folin-Ciocalteu method), antioxidant activity (ferric-reducing/antioxidant power) and free radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl free radical method). The response surface methodology (RSM) was used to evaluate the effect of the solvent (water/ethanol) and the extraction time, on the total phenolic content and antioxidant properties. The analysis of variance (ANOVA) indicated that the concentration of water in the solvent mixture significantly affected the yield of the compounds, as well as the antioxidant and antiradical activities. According to the RSM, the optimal extraction conditions are 25% water in the solvent mixture and a sonication time of 16 min.