Application of Low-Melting Mixtures Based on Choline Chloride with Organic Acids for Extraction of Phenolic Compounds from Vaccinium vitis-idaea L. Leaves

This study presents the results of continued work on the search for the most suitable low-melting mixtures (LMMs) for the ultrasound-assisted extraction of phenolic compounds from Vaccinium vitis-idaea L. leaves using LMMs of choline chloride, malonic, malic, tartaric, and/or citric acids combined with water. Kinetics of extraction was studied, and Box–Behnken experimental design coupled with Response Surface Methodology was applied to optimize extraction conditions. The most suitable composition of solvent was choline chloride + citric acid + water in a molar ratio of 1:1:16. The optimal extraction conditions were as follows: extraction duration of 30 min, temperature of 30 °C, and volume-to-mass ratio of 20:1. Under these conditions, the yields were 335.1 ± 18.7 mg gallic acid equivalent/g for total phenolic contents and 50.9 ± 3.6 mg rutin equivalent/g for total flavonoids content. The advantage of using LMMs over ethanol has been shown. The effect of the extract on the development of Drosophila melanogaster was also evaluated. The data obtained can be applied to the development of green technologies for the production of extracts from medicinal plant raw materials.