Dihydromyricetin is a natural flavonoid and principal component of the Chinese herbal tea, Ampelopsis grossedentata, with numerous health-promoting bioactivities. Response surface methodology (RSM) was employed to optimize the extraction of dihydromyricetin from Ampelopsis grossedentata leaves using dynamic microwave assisted multi-stage countercurrent extraction. The influence of temperature, pH, time and solvent/material ratio on the yield of extraction was investigated. It was found that the extraction data were sufficiently fitted into a second-order polynomial model (R2 = 0.9992). The extraction parameters of temperature, pH and solvent/material ratio, the quadrics of time, temperature and pH, and the interaction between each two of the four extraction parameters had a significant effect on the yield. The optimal conditions for extracting dihydromyricetin were predicted to be: temperature, 96.8 °C; time, 8.8 min; solvent/material ratio, 26.4/1 and pH, 5.3. Under those conditions, the predicted yield was 92.3% of dihydromyricetin in the leaves.

Wei Li, Yuzhen Chen, Xiang Xu, Cheng Zheng and Jian Zhao