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基于在H2SO4,Na2SO4介质中稳定存在的Ce(IV)的还原,在320 nm时,采用紫外可见分光光度计测定Ce(IV)吸光度,建立还原率与样品浓度的剂量关系,以线性关系的斜率为主要评价指标,评价样品的抗氧化活性。结果表明:针对5种结构相近的黄酮化合物,抗氧化活性顺序为:槲皮素>山奈酚>木犀草素>芹菜素>黄芩素;针对中药植物湖北旋覆花,抱石莲和吉祥草的提取物,正丁醇、乙酸乙酯部位是抗氧化活性成分的主体部位,但在旋覆花和抱石莲中,正丁醇部位抗氧化活性更强,而在吉祥草中,乙酸乙酯部位明显强于正丁醇部位;此外,不同提取方法得到的提取物抗氧化活性不同,低温回流和超声提取均可提高效率,但超声提取的时间应该控制在30 min以内。本评价方法操作简单,结果稳定可靠,检测限低,适合于天然产物抗氧化活性植物及活性部位的快速筛选。
Based on the stable reduction of Ce (IV) in H2SO4 and Na2SO4 medium, the absorbance of Ce (IV) was measured by UV-Vis spectrophotometer at 320 nm to establish the dose-dependent relationship between the reduction rate and the sample concentration. The slope of the linear relationship As the main evaluation index to evaluate the antioxidant activity of the sample. The results showed that for the five flavonoids with similar structures, the order of the antioxidant activity was quercetin> kaempferol> luteolin> apigenin> baicalein. According to the extraction of Chinese medicinal plants, Butanol and ethyl acetate were the main parts of the antioxidant active ingredients. However, the n-butanol part had stronger antioxidant activity in Inula and boulder, while in the auspicious grass, the ethyl acetate fraction was obviously But stronger than that of n-butanol. In addition, the antioxidant activity of extracts obtained by different extraction methods was different. Both low temperature reflux and ultrasonic extraction could improve the efficiency, but the time of ultrasonic extraction should be controlled within 30 min. The method has the advantages of simple operation, stable and reliable results and low detection limit, and is suitable for rapid screening of natural products and antioxidative active plants and active sites.