Optimization of DPPH Radical Scavenging Activity by Response Surface Methodology in The Ultrasonic-Assisted Extraction of Lespedeza bicolor Turcz.

Abstract

The objective of this study was to determine the ultrasonication-assisted extraction conditions that maximize the DPPH radical scavengingactivity of extracts obtained from the stems of Lespedeza bicolor Turcz through the application of the Response Surface Methodology(RSM). Before delving into the analysis of extraction conditions using the RSM model, we conducted efficiency validation ofultrasonication-assisted extraction and executed single-factor experiments for ethanol concentration, extraction time, and extractiontemperature. The data obtained from these single-factor experiments were employed to construct the Box-Behnken Design (BBD). Inthese results, in the single-factor experiments, it was evident that the parameters for ethanol concentration, extraction time, and extractiontemperature exhibited quadratic trends. The single-factor experiments allowed us to discern the trends for each parameter leading tothe maximum antioxidant capacity, and this data was subsequently applied to the BBD. Following the completion of initial experiments,a Response Surface Methodology (RSM) model was constructed based on Box-Behnken Design (BBD). According to the predictivemodel developed in this study, it was anticipated that performing ultrasonic-assisted extraction for 85.0412 minutes at an ethanolconcentration of 32.573% and an extraction temperature of 51.5608°C will result in a DPPH radical scavenging activity of 79.7146%. The predictive results were statistically verified through a comparative analysis with actual measurements and ANOVA analysis, confirmingthe statistical significance of the model. The finding of this study underscore the significance of optimizing extraction conditions inthe precise quantification of the antioxidant potential for economic advantages in both experimental and industrial contexts.