Ultrasonic-extraction of phenolic compounds from Phyllanthus urinaria: optimization model and antioxidant activity

Abstract

Ultrasonic-assisted extraction technique was used to extract phenolic compounds from Phyllanthus urinaria and response surface methodology was used to optimize the extraction parameters including ultrasonic time (X₁), ethanol concentration (X₂) and solid-liquid ratio (X₃). A mathematical model of the tree parameters for the high extraction yield (Y) was established. Antioxidant activity of the phenolic compounds was investigated by DPPH free radicals, ABTS free radicals, hydroxyl free radicals and reducing power assay with vitamin C as a control. The results showed that the independent variables (X₁, X₂ and X₃) and the interaction terms (X₁X₃ and X₂X₃) had a significant effect on the extraction yield. The effect of the variables on the extraction yield was in the order of X₃, X₁ and X₂. The optimal extraction process was X₁ of 34 min, X₂ of 46.5% and X₃ of 1:63 g/mL, and the extraction yield was 9.59%, which was well matched with the predicted value. The antioxidant activity assay indicated that the phenolic compounds from Phyllanthus urinaria have a good antioxidant activity.

Keywords:
ultrasonic extraction; response surface methodology; phenolic compounds; antioxidant activity