Microwave-assisted Extraction of Flavonoids fromScutellaria baicalensis Georgi

摘要

In the last 10 years there has been an increased interest in using technique -microwave-assisted extraction (MAE) in analytical laboratories. Microwave-assisted extractionwas applied to the extraction of four major flavonoids from Scutellaria baicalensis Georgi, namely,baicalin, baicalein, wogonoside and wogonin. The influence of parameters such as the nature ofsolvent and volume, extraction temperature, extraction time, power of irradiation and particle sizeof the matrix on percentage extraction was investigated. Percentage extractions of flavonoidsfrom Scutellaria baicalensis Georgi under the different methods and different microwaveprocessing conditions were compared in this paper. The experiment results shown that method,the nature of solvent and solvent- sample ratio are the key factors. Flavoniod compoundsextraction ratio of single extraction step in 10 minutes was greater than one of 3 hours for thereflux and 1 hour for the supersonic extraction. MAE allows reduced solvent consumption andshorter extraction times, while the rate of the flavonoids extraction was significantly greater usingmicrowave-assisted extraction than that of traditional reflux or supersonic extraction. The mostfavourable conditions were obtained to be ethanol concentration 50%(v/v) at power 600W , 90°Cfor 8 minutes and particle size 40 mesh. MAE is a simple, rapid and safe method, and isappropriate for extracting flavonoids from Scutellaria baicalensis Georgi.