Optimization of Microwave Assisted Extraction Conditions for Total Flavonoids in Toona Sinensis Leaves Using Response Surface Methodology

In this study Microwave assisted extraction (MAE) was employed to extract total flavonoids (TF) from the Toona sinensis leaves (TSL). Single factor experiments to evaluate the effects of the process parameters (extraction duration, solvent-solid ratio, ethanol volume fraction, and extraction times) on TF yield of TSL was performed, and response surface methodology (RSM) were used to optimize the extraction parameters. The analysis of variance indicated that the linear coefficients extraction duration, the quadratic terms of extraction duration and solvent-solid ratio, had highly significant effects on the TF yield (P<0.01). And, the quadratic terms of ethanol volume fraction had significant effects on the TF yield (P<0.05). The optimal conditions to obtain the maximum TF yield from TSL were extraction duration 85s, solvent-solid ratio (v/w, mL/g) 20, ethanol volume fraction 50%, microwave power 700 W, and repeated extraction two times. Under these optimal conditions, the TF yield was up to 2.39%. The analysis of variance (ANOVA) and validation test indicated that the method is useful and reliable.