Optimization of valuable bioactive compounds extraction from Mulberry leaves using agitated solvent extraction method

This study was conducted to optimize valuable bioactive compounds extraction from mulberry leaves using agitated solvent extraction through Box-Behnken response surface methodology. The effects of process independent variables including temperature (25-45 ºC), agitation intensity (100-300 RPM) and extraction time (2-6 h) on the extraction yield of valuable bioactive compounds were studied. In this study, the optimized conditions aimed to obtain highest extraction yield were 38 ºC, 235 RPM and 5 h of extraction time. Under these conditions, the extraction yield was 20.05%. The results revealed that the model obtained explains the relationship between the independent variables and response very well and also suitable for predicting extraction yield using any combination of values for the independent variables. Antioxidant activity of extract obtained under optimized conditions was determined using Diphenyl Picrylhydrazyl (DPPH) and Hydrogen peroxide (H2O2) assays. The total phenolic content (TPC) of the extract was determined by Folin-Ciocalteu reagent. The TPC and antioxidant activity measured using DPPH and H2O2 assays were 38.12±0.15 mg GAE/g extract, 66.54±0.12% and 4.87±0.16%, respectively. Finally, the results obtained were compared with the results of Soxhlet extraction method. The results revealed that applying agitated solvent extraction led to obtain more extraction yield with higher antioxidant activity within shorter extraction time.