Investigation of oligomeric proanthocyanidins extracted from Rhodiolae Crenulatae Radix et Rhizomes using deep eutectic solvents and identified via data-dependent-acquisition mass-spectroscopy

In this study, 34 deep eutectic solvents (DESs) were successfully prepared for the extraction of proanthocyanidin from Rhodiolae Crenulatae Radix et Rhizomes. The extraction process was optimized using single factor exploration and Box-Behnken design-response surface analysis. The extraction rate was significantly improved when the molar ratio of choline chloride to 1,3-propanediol was 1:3.5 and the water content was 30% (