Green solvents-based rutin extraction from Sophora japonica L.

Using green solvents to extract bioactive ingredients from medicinal herbs is a new trend for sustainable development procedures. The main objective of this study was to evaluate the ability to extract rutin from Sophora japonica L. using deep eutectic solvents (DESs), recover the target compound from extract, and reuse the solvent. Additionally, the antioxidant activity and cytotoxicity of the DESs extracts were also assessed. DESs of choline chloride and ethylene glycol (ChCl-Eth) showed the highest extraction efficiency of rutin from Sophora japonica L. The main factors affecting extraction yields were optimized by the response surface methodology (RSM). Under optimized conditions, the extraction yields using DESs and methanol as solvents were 26.20 % and 19.49 %, respectively. Water (as an antisolvent) was used to recover rutin from the DESs extract with a recovery yield of 94.9 %. The DESs solvent was recovered and recycled at least three times without loss of extraction yields. The DESs of ChCl-Eth had no significant effect on the antioxidant activity of rutin and the recovered rutin has exhibited more antioxidant activity than methanol extract. The selected greens solvents and their extracts did not show cytotoxic activity against the human embryonic kidney cell line (HEK-293A). The results serve as a basis for the development of other studies, as a premise to deploy a safe and environmentally friendly process of extracting natural active ingredients on an industrial scale.