Optimisation of extraction conditions of phenolic compounds and antioxidant activity of Ruta chalepensis L. using response surface methodology

In the present study, the extraction conditions of phenolic compounds from the Ruta chalepensis L. (a medicinal plant) and the antioxidant activity of its extract were determined. The response surface methodology (RSM) flowing Box-Behnken design was used to study and optimise the effect of three factors [ethanol concentration (40-80%), sample to solvent ratio (0.05/10-0.5/10g/mL) and extraction time (30-90min)] on the total phenolic content (TPC) and the antioxidant activity (AA). The optimal extraction conditions predicted by the models were 50.33%, 0.28g/10mL, and 59.86min for the ethanol concentration, the sample to solvent ratio and the extraction time, respectively. These factors gave the optimal predicted values of 521.10mg GAE/g DW and of 60.48mg AAE/g DW for the total phenolic content and the antioxidant activity, respectively. Total flavonoids (TFC), flavonols (TFlC), and ortho-diphenols (ODC) contents were further determined by evaluating the extract obtained by the validated optimal conditions of phenolic compounds. The obtained contents were 129.72 +/- 1.09mg QE/g DW, 24.98 +/- 0.38mg RE/g DW and 45.93 +/- 0.37mg CAE/g DW for TFC, TFlC, and ODC, respectively. The data of this report revealed that the extract of Ruta chalepensis L. is an excellent source of natural antioxidants that can be used or incorporated, as natural additives, into different food products in order to develop novel functional food products.