UV-Vis光谱差减法测定油橄榄叶中橄榄苦苷含量初探

Study on the Content Determination of Oleuropein in Olea europaea L. Leaves by Substraction of UV-Visible Spectroscopy

建立了紫外-可见(UV-Vis)分光光谱测定油橄榄叶中橄榄苦苷含量的方法。以芦丁和橄榄苦苷为对照品,分别采用NaNO2-Al(NO3)3-NaOH络合体系和AlCl3络合体系进行显色。以NaNO2-Al(NO3)3-NaOH体系显色后于510 nm处可测得油橄榄叶中总黄酮和橄榄苦苷的吸光度之和;而以AlCl3体系显色后于415 nm处仅测得总黄酮的吸光度,橄榄苦苷无吸收。利用橄榄苦苷在两种显色体系中的吸收特性差别,通过差减法换算后可间接测定样品中橄榄苦苷的含量。以UV-Vis差减法测得油橄榄叶及其纯化浸膏中橄榄苦苷的平均含量分别为11.6%和63.4%,3次测定的相对标准偏差(RSD)分别为1.5%和1.2%,其结果与高效液相色谱法(HPLC)测定结果的相对误差小于4.0%。该方法可替代HPLC用于油橄榄叶中橄榄苦苷的含量测定,为油橄榄叶及其制品的质量控制提供了一种快速、简便、成本低廉的分析方法。

The content of oleuropein was usually determined by high performance liquid chromatography（HPLC） or gas chromatography（GC） method in previous studies. In this paper, a method for the determination of oleuropein in Olea europaea L. leaves was developed using a substraction of UV -Visible spectroscopy. With the standard rutin and oleuropein, two coloration systems including NaNO2 -Al （NO3 ）3 -NaOH and AlCls were both used. The total absorbance of total flavonoids and oleuropein was obtained at a wavelength of 510 nm in the former coloration system. In the latter coloration system, the absorbance of total flavonoid was obtained at a wavelength of 415 nm, but oleuropein was not detected at 415 nm in this system. According to the above absorhanee properties, the content of oleuropein could be indirectly learned by substraetion of the absorbanees obtained in the two coloration systems. By using the developed UV - Vis method, the average contents of oleuropein in the olive leaves and purified extractums were 11.6% and 63.4% with RSDs （n = 3 ）of 1.5% and 1.2% , respectively. Compared with the content determined by HPLC method, the relative error of this method was less than 4% . The result showed that this method could be used to replace the HPLC method for the determination of the content of oleuropein in the olive leaves or its products as the former was more simple, faster and lower cost than the latter. It can be looked as a reference method for the indirect determination of the active components in herbal materials or natural products.