Chemical compositions and bioactivities of essential oil from perilla leaf (Perillae Folium) obtained by ultrasonic-assisted hydro-distillation with natural deep eutectic solvents.

Natural deep eutectic solvents (NADESs) have received considerable attention for green extraction. In this study, ultrasonic-assisted natural deep eutectics were applied for hydrodistillation to extract essential oil from perilla leaves. Compared to hydrodistillation assisted with ultrasound, this novel method effectively raised the yield of perilla leaf EO from 0.21% to 0.69% (choline chloride: malic acid, molar ratio 2:1) and broadened the types of chemical compositions (71 in total), especially aliphatic and aromatic compounds. Stronger antimicrobial and antioxidant activity was confirmed, and phenolics were increased. Additionally, the pH of the final solution was detected. The leaf residues were dried, weighed and analyzed by scanning electron microscopy to show the influence of NADESs' strong extractability. This new extraction method may be applicable in edible natural product extraction and provide a reference for further exploration of NADESs.