Green and highly effective extraction of bioactive flavonoids from Fructus aurantii employing deep eutectic solvents-based ultrasonic-assisted extraction protocol

In China, Jiang Fructus aurantii (JFA) has attracted increasing interest as a famous traditional herbal medicine and valuable economic food for its valuable medicinal and industrial properties. In the current work, contrasted with conventional extraction techniques, natural flavonoids from JFA (naringin and neohesperidin) were extracted with remarkable effectiveness utilizing a sustainable deep eutectic solvents combined ultrasonic-assisted extraction (DESs-UAE) protocol. The optimal extraction capacity can be achieved by mixing 30 % water with a molar ratio of 1:3 for choline chloride and ethylene glycol, as opposed to the classical extraction solvents of 95 % ethanol, methanol, and water. Moreover, the DESs-UAE extraction programs were also systematically optimized employing Box-Behnken design (BBD) trials, and the eventual findings suggested that the best parameters were a 27 % water content in DES, a 16 mL/g liquid-solid ratio, a 72 min extraction time, and a 62 °C extraction temperature, along with the corresponding greatest contents of NAR (48.18 mg/g) and NEO (34.50 mg/g), respectively. Notably, by comparison with the pre-optimization data, the optimized DES extraction efficiency of flavonoids is markedly higher. Thereafter, the characterization of the solvents before and after extraction, as well as the differences between the four extraction solvent extracts, were compared using the FT-IR analyses. Furthermore, SEM results suggested that the penetration and erosion abilities of the plant cell wall of DES-1 were stronger than those of the other three traditional solvents, thus allowing more release of flavonoid compounds. In conclusion, the present research develops a straightforward, sustainable, and exceedingly efficient approach for the extraction of bioactive flavonoids from JFA, which has the potential to facilitate the efficient acquisition of active ingredients from TCM.