定量核磁共振波谱法测定黄芩中的黄芩苷含量研究

Determination of Baicalin in Scutellariae Radix by Quantitative Nuclear Magnetic Resonance Spectroscopy

目的:建立核磁共振波谱法测定黄芩中黄芩苷的含量。方法:以黄芩苷作为评价黄芩质量的指标,利用超声波提取法提取黄芩苷,采用核磁共振波谱法测定黄芩中黄芩苷的含量。以吡嗪为内标,氘代二甲基亚砜(DMSOd6)为溶剂,观测频率600 MHz,脉冲延迟时间1 s,扫描32次,采集黄芩苷的1H-NMR谱图,定量峰黄芩苷质子信号δ5.24(d 5.23)。结果:黄芩苷的提取条件为65%甲醇,料液比为1:20,在50℃下,超声提取1 h;1H-qNMR结果表明,黄芩苷在115.3~3546.7μg/mL浓度范围内呈现良好的线性关系(r=0.9998),精密度为0.597%,回收率为101.015%~104.091%,相对标准偏差为1.044%。1H-qNMR测得黄芩中黄芩苷平均含量为11.914%。结论:本研究建立的氢核磁定量方法操作简单、快捷,方法可靠,可运用于快速测定黄芩中黄芩苷的含量,并为其含量检测提供了新的途径。

Objective:To establish a quantitative1H-NMR method for the determination of baicalin in Scutellaria baicalensis. Methods:Baicalin was used as an index to evaluate the quality of baicalensis,which was extracted by ultrasonic extraction,and the content of baicalin in baicalensis was determined by NMR spectroscopy. Pyrazine was chosen as the internal standard,deuterium substituted(DMSO-d6)as the solvent,the observation frequency was 600 MHz,the pulse delay time was 1 s,and the scanning time was 32 times,the1H-NMR hydrogen spectrum of baicalin was collected to determine the quantitative peak baicalin proton signal of 5.23(d 5.24).Results:The extraction conditions of baicalin were 65%methanol andwith a feed to liquid ratio of 1:20. The extraction was carried out at 50 ℃ with ultrasonic extraction for 1 h. The results of1H-qNMR showed that baicalin presented a good linear relationship in the concentration range of 115.3~3546.7 μg/mL(r=0.9998),the precision was 0.597%,the recovery were101.015%~104.091%,and the relative standard deviation was 1.044%. The average content of baicalin in baicalensis was 11.914% as measured by1H-qNMR. Conclusion:The 1H-qNMR quantification method established in this study is simple,rapid and reliable. It can be applied to the rapid determination of baicalin in baicalensis and provides a new way for its content detection.