Natural deep eutectic solvent extraction of chlorogenic acid from Eucommia leaves: high extractability, stability, antibacterial, and antioxidant activity

Abstract

Chlorogenic acid (CGA) is a natural compound with potent antioxidant and antibacterial properties that can be extracted from Eucommia leaves (EL). In this study, we investigated eight natural deep eutectic solvents (NADES) for their effectiveness in extracting CGA from EL. The extractability, stability, antibacterial and antioxidant activity of the CGA extracted by NADES were evaluated and compared with traditional solvent extraction. The results of the study revealed that the highest efficiency in extracting CGA was achieved using choline chloride–malic acid (ChCl–MA) NADES, which can be recycled four times. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) characterization of solid residues confirmed high extraction. The acidic and high-strength hydrogen-bonding features of ChCl–MA contribute to the enhanced stability of CGA. The presence of malic acid components in ChCl–MA can synergistically improve the antioxidant and antimicrobial bioactivity of the extraction solution. The results of this study provide a promising and sustainable method for NADES to extract natural products in food chemistry and pharmacy.