Research on the Flavonoids Extracted from Ginkgo Leaf with Microwave and its Antioxidant

[Objective] The basis of the large-scale extraction and development of the flavonoids from ginkgo leaf and its integrated utilization was provided through the study on the microwave extraction process of ginkgo leaf flavonoids and the determination of its antioxidant capacity in vitro.[Method] The effect of the concentration of ethanol,the ratio of material to liquid,the radiation time and the refluxing temperature on microwave extraction process of ginkgo leaf flavonoids was researched with single factor experiment.The scavenging effect of ginkgo leaf flavonoids to superoxide anion and hydroxyl radical was tested.[Result] The order of the factors affecting the microwave extraction was the concentration of ethanol the ratio of material to liquid the radiation time refluxing temperature.The ginkgo leaf flavonoids had the strong scavenging function to superoxide anion and hydroxyl radical,which was strengthened with the amount increasing of flavonoids.[Conclusion] The best condition of the ginkgo leaf flavonoids extraction with the microwave was the concentration of ethanol,50%;the ratio of material to liquid,1∶25;the refluxing temperature,70 ℃ and the treatment time of microwave,120 s,under which,extraction rate of total flavonoids was 11.02%.The ginkgo leaf flavonoids had good anti-oxidation,which was a natural and effective antioxidant.