差示分光光度法在番石榴叶总黄酮提取工艺中的应用

目的]建立番石榴叶总黄酮含量的测定方法，并对番石榴叶总黄酮提取工艺进行优化。方法]以浓度2％的ZrOCl2·8H2O甲醇溶液为显色剂，测定波长为412nm，以芦丁为对照品绘制标准曲线，建立番石榴叶总黄酮含量的测定方法。在单因素试验的基础上，以总黄酮得率为主要考察指标，干膏收率为次要考察指标，考察料液比、乙醇浓度、提取时间和提取次数对提取效果的影响，并采用正交试验筛选出最佳提取条件。结果]计算得线性回归方程为：Y=31．3850x-0．0255（R=0．9999），表明在0～0．024mg／ml范围内，芦丁浓度与吸光度的线性关系良好。优化的提取工艺为：乙醇浓度40％，料液比1：20（g／ml），提取时间1h，提取次数3次；在此条件下，番石榴叶总黄酮的提取率为3．30％，干膏得率为27．8％。结论]差示分光光度法操作简单易行、快速、准确，适用于黄酮类化合物的含量测定。通过正交试验优选得到的番石榴叶总黄酮的提取工艺条件稳定可行，对番石榴叶总黄酮的合理开发利用提供理论依据。

Application of Differential Spectrophotometry in the Extraction of Total Flavonoids from Psidium guajava Leaf

Objective ] To establish the determination method of total flavonoids and optimize the extraction process for total flavonoids from Psidium guajava leaf. Method] With 2% ZrOC12. 8H20 methanol solution as the chromogenic agent, determination wavelength 412 nm, the standard curve was made with rutin as the control article, and the determination method was established. On the basis of single factor experiment, effects of ethanol concentration, solid - liquid ratio, extraction period and times were studied by taking the yield of total flavonoids as the main index and the dry paste yield as the secondary indicator. The proper condition was determined by orthogotud experiment. Result] The linear re- gression equation is y =31. 385 0x - 0. 025 5 （R =0. 999 9）, indicating that the linear relationship between rntin concentration and absorbance is good within the range of 0 -0.024 mg/ml. The orthogonal test showed that the ethanol concentration, the solid -liquid, the extraction period, the extraction times were 40%, 1： 20, 1 h, 3times. Under this condition, the extraction rate of total flavonoids reached 3.3%, the dry paste yield reached 27.8%. Conclusion ] Differential spectrophotometry is simple, rapid, accurate and is suitable for determination of total flavonoids in Psidium guajava leaf. The optimized process is feasible for the extraction of total fiavonoids. This study could provide theoretical basis for the proper development and utilization of total flavonoids from Psidium guajava leaf.