Evaluation of natural deep eutectic solvents for the extraction of bioactive flavone C-glycosides from Flos Trollii

Nowadays, deep eutectic solvents (DESs) are emerging as a new type of green and sustainable solvents for efficient extraction of bioactive compounds from natural products. In the present study, to evaluation of DESs for the extraction of flavone C-glycosides, a total of twelve choline chloride based DESs were tailored for simultaneous extraction three main bioactive flavone C-glycosides (2″‑O‑galactopyranosylorientin, orientin and vitexin) from Flos Trollii. The DES composed of choline chloride and zinc bromide showed the best extraction efficiency for the flavone C-glycosides compared with conventional organic solvents (methanol and 50% methanol). Subsequent, the extraction parameters for the three flavone C-glycosides, including liquid-solid ratios, water content (%) in the selected DESs, and extraction time were optimized using response surface methodology and the optimal extraction condition are liquid-solid ratio, 42 mL/g; water content, 48%; extraction time, 28 min. In addition, the three flavone C-glycosides were recovered from DESs by macroporous resin (D101) with a satisfactory yield between 75.4% and 80.5%. The present research indicated that DESs were efficient and sustainable for extraction main flavone C-glycosides from Flos Trollii and the data acquired in this study could contribute to further DESs application in extraction of bioactive compounds from natural products.