Optimization, biological activity, and mechanism study of resin in-situ adsorption assisted extraction of phenolic compounds from Perilla frutescens Leaves

A strategy of resin adsorption-assisted deep eutectic solvent (DES) extraction of Perilla frutescens leaves phenolic compounds was proposed. The DES based on choline chloride-acetic acid (molar ratio 1:2) and D301 resin containing tertiary amine groups served as extractant and adsorbent. After 10 repeated uses of resin, the extraction yield did not decrease significantly. FTIR and 1 H NMR characterization results indicated the successful preparation of DES. Under optimal conditions, the total polyphenols and flavonoids content of extract were 2.75 times and 23.95% higher than those of DES extract without resin, respectively. UPLC-MS analysis identified 53 polyphenols. The extract showed strong antioxidant activity and starch-digesting enzyme inhibition. Conductor-like Screening Model for Real Solvents (COSMO-RS) calculation, weak interactions calculation, and molecular docking indicated that DES and resin jointly promote extraction through hydrogen bonding and van der Waals forces.