Optimization of ultrasound-assisted extraction of phenolic compounds from verbena officinalis l. leaves using response surface methodology and evaluation of its antioxidant activities

The ultrasound-assisted extraction of phenolic compounds from Verbena officinalis L. leaves parts was modeled using response surface methodology. Central Composite Design has been used to optimize four extraction parameters: extraction time (t), ultrasonic temperature (T), liquid-to-solid ratio (R) and pH (pH) in order to get a phenolic rich extract. The optimized conditions are t = 30.64 min, T = 52.70 degrees C, R = 28.71 ml/g and pH = 5.22. Under these conditions, the experimental TPC= 87.089 mg GAE/g DW, TFC= 52.706 mg QE/g DW, IC50= 27.975 mu g/ml and FRAP assay= 992.566 mu M BHT/g DW. Consequently, this optimized UAE method has demonstrated a potential application for efficient extraction of phenolic compounds from Verbena officinalis L. leaves in the nutraceutical industries.