Comparison of refluxing, ultrasonic- and microwave-assisted extraction of dihydromyricetin from Ampelopsis grossedentata.

Three techniques--refluxing extraction (RE), ultrasonic-assisted extraction (UAE), microwave-assisted extraction (MAE)--for extraction of dihydromyricetin from Ampelopsis grossedentata, family Vitaceae, were evaluated. A 70% methanol-water solution was used as extraction solvent, and extracts obtained were analyzed by high-performance liquid chromatography (HPLC). Results showed that the MAE method was the most efficient in the shortest time, followed by RE and UAE. Maximum extraction efficiency of dihydromyricetin was obtained by using the MAE technique, which needs only 10 min, whereas UAE and RE require 40 and 300 min, respectively, to gain higher extraction efficiency of dihydromyricetin. The time needed for MAE was 30 times less than that needed for RE. Extracts obtained by using different methods were shown by HPLC analysis to possess similar chemical constituents, and extraction reproducibility was satisfactory for these techniques. Compared with UAE and RE, the MAE is a better alternative extraction technique for large-scale speedy extraction of dihydromyricetin from this plant.