氢核磁共振法测定中药茜草中大叶茜草素和羟基茜草素的含量

综合运用一维和二维核磁共振波谱技术,对茜草提取物中大叶茜草素、羟基茜草素的信号进行指认归属,并建立氢核磁共振法同时测定茜草中大叶茜草素、羟基茜草素含量的方法。在综合考虑茜草提取物的信号分离度及溶解性的基础上,最终选定氘代二甲基亚砜为测试溶剂,以大叶茜草素的烯烃信号(δ_H5.77,H-2')和羟基茜草素的H-3信号(δ_H6.67)为定量峰,以顺丁烯二酸为定量内标。该方法具有较好的稳定性、重复性、精密度和准确性,且测定结果与HPLC-UV方法所得数据基本一致。所建立的氢核磁定量方法操作简单,测试时间短,且定量过程中不需要对照品,可用于中药茜草的质量控制及评价。

Quantitative determination of mollugin and purpurin from traditionalChinese medicine Rubiae Radix et Rhizoma by 1H NMR

The ¹H chemical-shift values of mollugin and purpurin in extract from Rubiae Radix et Rhizoma were assigned on the basis of 1D and 2D NMR, and a specific, simple, sensitive 1H NMR method has been developed and validated for the simultaneous quantitative determination of mollugin in extract from Rubiae Radix et Rhizoma When the solvent effects on the resolution of target signals and the solubility of the crude extracts were taken into account, dimethyl sulfoxide-d₆ was selected as an optimal ¹H NMR solvent. Quantitative determination was carried out by using the signal of the olefinic proton of mollugin (δ_H 5.77, H-2′) and H-3 of purpurin (δ_H 6.67), which were not interfere with other signals. Maleic acid was selected as internal standard because of its stable physical and chemical properties and having simple resonance signal. The improved method possessed good stability, repeatability, precision and accuracy for the quantification of mollugin and purpurin and the determination results agreed with the data obtained by HPLC-UV method. Due to its simple operation, short test time and without any reference