Optimization of Green Extraction Process of Total Flavonoids from Dendrobium officinale Flower

Objective: To make full use of the flavonoids in Dendrobium officinale flowers, a green and efficient extraction process was developed. Methods: Taking the yield of flavonoids from Dendrobium officinale flowers as an index, using new deep eutectic solvents, based on single factor experiments and response surface methodology, the extraction process of total flavonoids was optimized. And macroporous adsorption resins were used to investigate the recycling capacity of DESs. Results: DESs composed of choline chloride and ethylene glycol (molar ratio 1:4) had the highest yield. The yield reached 22.457 mg/g under the optimal extraction conditions (water content 18.9 %, temperature 88.2 ℃, liquid-solid ratio 23.3:1 mL/g, time 38.0 min). The adsorption rate and desorption rate of ADS-8 for total flavonoids were 78.32% and 83.55%, respectively, and the recycling rate of recovered DESs reached 95.47%. Conclusion: The deep eutectic solvent was an efficient and green method that could be recycled to extract the total flavonoids from Dendrobium candidum flowers.