Study on Microwave Extraction Process of Total Flavonoids from Vaccinium Bracteatum Thunb. Leaves by Orthogonal Design

OBJECTIVE To optimize the microwave extraction process of total flavonoids in leaves of Vaccinium bracteatum Thunb.. METHODS Ultraviolet spectrophotometry was used to determine the total flavonoids in Vaccinium bracteatum Thunb. leaves. While the transferring rate of total flavonoids was taken as index, single factor and L₉(3⁴) orthogonal test was employed to optimize the microwave extraction process parameters including extraction temperature, extraction time, ethanol concentration, degree of pulverization and material liquid ratio. RESULTS The optimum of microwave extraction process was as followed:the Vaccinium bracteatum Thunb. leaves was smashed and filtrated through 80 mesh, then 70% ethanol was added at the material liquid ratio of 1:40; the microwave extraction process was performed at the temperature of 70℃ and microwave power of 250 W for 10 min. Under this condition, the verification test results showed that the transferring rate of the total flavonoids of Vaccinium bracteatum Thunb. leaves was 91.34% and the purity was 21.53%(RSD=0.75%, n=3). CONCLUSION Microwave extraction has the advantages of high efficiency, brief and low energy consumption, and the optimized extraction process is stable, which provides a reference for follow-up study of Vaccinium bracteatum Thunb. leaves.