Optimization of the Ultrasound-Assisted Extraction of Phenolic Antioxidants from Cistus Salvifolius L. Using Response Surface Methodology.

The current work aims to optimize the ultrasound-assisted extraction (UAE) of Cistus salviifolius L. (aerial parts) antioxidative phenolic compounds using response surface methodology. A Box-Behnken design has been conducted to investigate the effect of four factors, namely: (i) percentage of ethanol (50-90 %, v/v), (ii) temperature (40-80 °C), (iii) solvent-solid ratio (10-50 mL g) and (iv) extraction time (5-25 min) on four responses, namely: total phenolic content (TPC), total flavonoid content (TFC) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition, and ferric reducing antioxidant power (FRAP).