The extraction of quercetm was performed by reflux extraction with extraction rate of quercetin as evaluation index and with the extraction time, ratio of solid to liquid, concentration of alcohol and the times of extraction as factors. The optimal condition of extraction was obtained by the orthogonal experiment. The content of quercetin was determined by ultraviolet spectrophotometry. The best extraction condition was the follows: the sample was extracted for 2 h with 90% (V/V) alcohol for 3 times, the ratio of solid to solution was 1:40. Quercetin in leaves of Psidium guajava L. harvested in March reached 2.95%. As a result, this method for detecting quercetin in leaves of P. guqjava was stable, quick, simple and met the requirements of methodology.%采用回流提取法,以槲皮素的提取率为评价指标,以提取时间、料液比、乙醇浓度和提取次数为考察因素,通过正交试验优化提取条件,并以紫外分光光度法进行定量分析.结果表明,番石榴叶中槲皮素的优化提取条件为90％乙醇(V/V)、料液质量比1∶40、每次提取2h、提取3次；槲皮素含量以3月份最高,达到2.95％.该法测定番石榴叶中槲皮素含量稳定、快速、简便,符合方法学考察要求.
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