Determination of the Content of Total Flavonoids in Red Jujube with Ultrasonic Extraction and Spectrophotometry

[Objective] A new method for the ultrasonic extraction and spectrophotometric determination of the flavonoids in red jujube was researched.[Method] The absorbance of the flavonoid,which was extracted with the ultrasonic method under the methanol as solvent from red jujube,and then,colorfully compounded by NaNO2-Al(NO3)3-NaOH,was measured with spectrophotometer in at λmax of 500 nm.[Result] The flavonoid compounds from red jujube were with a good linear relationship in the range of 0.004 8-0.047 0 mg/ml and its regression equation was Y=25.625X+0.023 7(R=0.999 0).The content of flavonoids from the red jujube of three different areas was in the range of 65.1 mg/100 g ~ 158.6 mg/100 g.The results showed that the content of flavonoids in red jujube was related to the origin and parts of jujube.The highest content of flavonoids was in the red jujube from the Qingjian region near the Yellow River and the content of flavonoids in jujube skin was higher that of its pulp and stone.[Conclusion] The method of the flavonoids extracted with ultrasonic technique from red jujube and the content of flavonoids accurately measured with spectrophotometer was set up.