The Development of a One-Step Method for Production of the Antioxidant Quercetin from Flower Buds of the Sophora Japonica (Sophora japonica L.) in a Subcritical Water Medium

The possibility of production of a natural antioxidant, quercetin, from flower buds of the Sophora japonica (Sophora japonica L.) using subcritical water both as a reagent and a solvent was investigated. The proposed approach allows one to avoid the use of costly and toxic organic solvents, does not require conducting separate steps of extraction and hydrolysis, and simplifies purification of the product. High quercetin yields were achieved within a time that was 13 times less than using traditional techniques. The losses of the target product during production of dry extract were reduced.