Two green approaches for extraction of dihydromyricetin from Chinese vine tea using β-Cyclodextrin-based and ionic liquid-based ultrasonic-assisted extraction methods

Dihydromyricetin (DMY) is the main flavonoid present in vine tea and is also known to possess various beneficial health effects. Extractions of DMY from vine tea were investigated by ultrasonic-assisted extraction (UAE) with β-Cyclodextrin (β-CD) and ionic liquid (IL), which were the two green extraction methods attracting more attentions in recent years. Single factor and response surface methodology (RSM) were used in order to optimize the extraction conditions for obtaining maximum amount of DMY in the two approaches. The results of HPLC analysis showed that the addition of β-CD or 1-hexyl-3-methylimidazolium bromide ([HMim] Br) to the water solution had excellent effects on the extraction of DMY. In β-CD-UAE, the optimum conditions were 3.6% β-CD, ultrasonic time 8 min, liquid–solid ratio of 33 (mL/g), and ultrasonic power 360 W. Molecular docking results indicated that the ‘host-guest’ effect between β-CD and the molecule of DMY in water solution, which utilized molecular recognition and interactions through non-covalent bonding and hydrogen bonding is the main driver of the binding. And for IL-UAE, the optimal conditions were 1.25 mol/L [HMim] Br, ultrasonic time 5.5 min, liquid–solid ratio of 45 (mL/g), and ultrasonic power 240 W. Under above suitable conditions, the extraction yield of DMY can reach to about 40%; moreover, β-CD-UAE and IL-UAE can be easily applied for experimental or industrial scale in food or functional food use.