Simultaneous Optimization of Ultrasound Pretreatment Extraction of Polyphenols Using Response Surface Methodology from Lamium album L.

Simultaneous ultrasound pretreatment extraction (UPE) process was optimized by means of response surface methodology (RSM) to maximize the extraction of the two most famous polyphenols, total hydroxycinnamic acids (THAC) derivatives and total flavonoids content (TFC) as hyperoside, from Iranian White Dead Nettle (Lamium album L.). A 5-level full factorial central composite design was successfully implemented for UPE optimization, in which temperature, extraction time, ethanol percent, ultrasonic pretreatment time and liquid/solid ratio were relevant independent variables. For maximizing the two responses simultaneously, the optimal processing conditions were as follows: 60% ethanol–water (volume-by-volume); temperature, 55 ºC; extraction time, 24 h; liquid/solid ratio, 12 (mL/g); and time of ultrasound pretreatment, 20 min which the desirability factor was 0.780. Statistical analysis and verification test indicate a satisfactory correlation between the experimental data and predicted values.