Integrated natural deep eutectic solvent and pulse-ultrasonication for efficient extraction of crocins from gardenia fruits (Gardenia jasminoides Ellis) and its bioactivities.

This study proposed natural deep eutectic solvent (NADES) based pulse-ultrasonication-assisted extraction (P-UAE) for green recovery of crocins from gardenia fruits (Gardenia jasminoides Ellis). Choline chloride-1,2-propylene glycol (ChCl-PG, 1:2.5, mol/mol) with 35 % (v/v) water content was tailor-made to obtain the highest extraction efficiency with high surface tension, polarity, conductivity, pH, and low viscosity, density for affinity-based extraction of crocins. The optimized P-UAE conditions (extraction time 120 s, ultrasonic power 400 W, solvent-to-solid ratio 40 mL g-1, extraction temperature 35 ℃) led to the maximum yield of crocins (36.97 mg g-1 DW). The second-order kinetic model was fitted to the extraction process and the synergistic effect was verified by SEM and FTIR. The crocetin was identified as the main compound by UPLC-Triple-TOF/MS. The antiglycative effect and protective effect on DNA indicated the bioactive activities of crocins. Therefore, the ChCl-PG based P-UAE could serve as a green strategy to effectively extract crocins from gardenia fruits.