Optimization of the process conditions for the extraction of rutin from Ruta graveolens L. by choline chloride based deep eutectic solvents

Extraction of rutin from Ruta graveolens L. leaves was performed in choline chloride based deep eutectic solvents (DESs). Firstly, rutin extraction was performed in five different DESs ; pure DESs and with different amounts of water added (25% and 50% v/v), for different times (1h, 3h and 6h) in order to find the best DES for further optimization. Choline chloride plus citric acid (1:1) was shown to be best DES and optimization of rutin extraction was performed using response surface methodology (RSM) based on the selected solvent and applying different extraction parameters: extraction time, temperature and water content. The rutin content was determined by HPLC and varied from 0.55 g/100 g of plant to 1.81 g/100 g of plant depending on the applied conditions. The best conditions for rutin extraction were found to be: a temperature of 70°C, an extraction time of 52 min and a water content of 27% for the extraction of 1.88g /100 g plant.