槐叶总黄酮含量的钼酸盐配合物差示分光光度法测定

Determination of the Content of Total Flavonoids in Leaves of Sophora japonica L. by A spectrometric Method with Forming the Conjugates of Na_2MoO_4-NaNO_2-NaOH

目的建立钼酸钠配合物差示分光光度法测定槐叶中总黄酮含量,对植物叶、茎或果实中总黄酮含量测定方法进行新的探索。方法槐叶干品经索氏提取法甲醇连续提取,得槐叶总黄酮样品测定液。以芦丁对照品作为标准。分别用芦丁对照品或槐叶总黄酮提取物与NaNO2-Na2MoO4-NaOH反应形成稳定配合物。以空白试剂溶液为参比,分别对芦丁或槐叶总黄酮提取液配合物溶液在200～500nm范围进行差示扫描。结果芦丁与槐叶总黄酮配合物溶液差示光谱图一致,有3个明显的吸收峰,在332 nm波长处浓度与吸光度呈现良好的线性关系,线性范围4～40μg.ml-1,回归方程A=0.002 1+0.028 04C,r=0.999 4,槐叶中总黄酮的平均回收率为95.7%,RSD为1.9%。结论槐叶总黄酮钼酸盐配合物差示分光光度法测定槐叶中总黄酮,操作简单易行,可较好解决背景吸收的问题,也对植物叶、茎或果实中总黄酮的含量测定方法进行新的探索。

Objective To establish a spectrometric method by forming the conjugates of Na2MoO4 - NaNO2 - NaOH with flavonoids for determining the content of total flavonoids in leaves of Sophora japonica L.. Methods The extraction of total flavonoids in leaves of Sophora japonica L. was prepared by a conseetive extraction with methanol. The stable conjugates formed by adding the Na2 MoO4 - NaNO2 - NaOH solution to the extract of total flavonoids. With authentic rutin as the standard, the conjugates of authentic rutin or the extract of total flavonoids with Na2MoO4 - NaNO2 - NaOH were differential scanned using the wavelengths ranged from 200 nm to 500 nm by a UV - VIS spectrometer. Results The differential spectrograms of authentic rutin or the extract of total flavonoids with Naz MoO4 - NaNO2 - NaOH were quite the same with three specific absorbance peaks. At wavelength of 332 nm, the linear correlation was revealed between the concentration of rutin and the absorbanee with the linear range of 4 - 40ug .ml-1. The regression equation was A =0.002 1 ＋ 0. 028 04C with a regression coefficient of 0. 999 4. The rate of recovery of the method was 95.7% with a RSD of 1.9%. Conclusion It is a simple and useful method to determine the content of total flavonoids in leaves of Sophora japonica L. by a spectrometric method with forming the conjugates of N% MoO4 - NaNO2 - NaOH, which can better solve the problem of background absorbanee and do a new explore for estimating the levels of total flavonoids in the leaves, stems, and fruits of plant.