Study on Extracting Total Flavonoids from Hypericum perfortum L. with Microwave-assisted Extraction

[Objective] The study aims to discuss the optimum technological conditions of extracting total flavonoids from Hypericum perfortum L.with microwave-assisted extraction.[Method] Microwave power,extraction solvent concentration,liquid-solid ratio,and extraction time are investigated and the appropriate microwave-assisted exteaction conditions are obtained with the orthogonal test method.The microwave-assisted exteaction method is compared with ultrasonic extraction and soxhlet extraction methods.[Result] The optimized conditions of microwave-assisted extraction are as follows: ethanol concentration is 70 %,liquid-solid ratio is 30∶ 1,microwave power is 450 W,and extraction time is 5 minutes.Also the extracting yield of flavoniods from Hypericum perfortum L.is up to 6.02 % under the optimal extraction conditions.The yield of total flavonoids is almost equal to soxhlet extraction method for 4 hours,and ultrasonic extraction method for 1 hours.[Conclusion] The microwave-assisted extraction method is a fast,efficient,energy saving and high-selective.