Optimization of the extraction process for flavonoids from basil (Ocimum basilicum) using response surface methodology

Basil (Ocimum basilicum), an edible and medicinal plant with high nutritional value and therapeutic efficacy, was used as a potential source of total flavonoids in this study. Heat reflux extractions were performed using aqueous ethanol. The optimized extraction conditions of total flavonoids from O. basilicum were determined by Box-Behnken design with response surface methodology. Response surface plots showed that the optional four independent variables significantly influenced the extraction yield of total flavonoids. The extraction parameters for the highest total flavonoids yield were optimized as:extraction temperature of 79.74℃, ethanol concentration of 77.63%, ratio of liquid to material of 29.72:1 (mL/g), and extraction time of 2.06 h. The average yield of total flavonoids under above optimum parameters was 42.61 mg of rutin equivalents per g of extract dry matter, which was in good agreement with the predicted value of 40.23 mg/g. These optimized conditions could be useful for the extraction of flavonoids from O. basilicum.