Quantitative Measurement of Artemisinin Content in Chinese Traditional Compound Medicine by Raman Spectroscopy
LI Jia-jia1*, LIU Jing-li1, JIN Ru-yi1, TANG Yu-ping1, YUE Shi-jun1，WANG Li-wen2, LONG Xu1, ZHANG Guang-hui1, MENG Qing-hua1, LI Rong-xi3
1. College of Pharmacy, Shaanxi University of Chinese Medicine, Xianyang 712046, China
2. First Affiliated Hospital, Shaanxi University of Chinese Medicine, Xianyang 712046, China
3. School of Earth Sciences and Resources, Chang’an University, Xi’an 710054, China
Abstract：Artemisinin is a kind of sesquiterpene lactone drug containing peroxide groups, which is extracted from Artemisia annua L. Now it has become an antimalaria drug recommended by the world health organization. The compound preparation of Chinese material medica containing artemisinin has strong anti-malarial, antibacterial and immunomodulatory effects. However, there is no measurable and generalized standard for controlling and evaluating the quality of the compound preparations. Currently, the main researches of artemisinin compound preparations focus on the qualitative analysis of the active ingredients, and only less work is aimed at how to quantitatively analyse the artemisinin content. Therefore, it is urgent to develop a convenient, rapid and nondestructive method to monitor the production and use of artemisinin. Laser Raman spectroscopy is a kind of molecule scattering spectroscopy, which is characterized by frequency excursion that is caused by interactions of molecules and photons, to obtain information on molecules. Laser Raman spectrometry is a potential method for quantitatively analyzing artemisinin content. In this study, we demonstrate that Laser Raman spectroscopy is a suitable and non-destructive technique to qualitatively analyze artemisinin. The spectral characteristics of artemisinin will provide standard Raman spectra for identification and analysis of artemisinin in Chinese traditional compound medicine. It is found that the vibrational mode at 724 cm-1 is related to the vibration of peroxide groups, and also it is the key to verifying its anti-malarial function, in Artemisinin. In addition, the phonon mode at 1 736 cm-1 is not affected by the surrounding vibrational modes and its intensity is strong. The vibrational mode at 1 736 cm-1 corresponds to the vibrational mode of lactone bond, so it could be used for detecting artemisinin. Hence, this paper attempts to adopt the characteristic vibrational modes at 724 and 1 736 cm-1 simultaneously to analyze Artemisinin qualitatively and quantitatively. A series of artemisinin/flour binary mixture with different artemisinin mass percentage were synthesized with the aim of obtaining Raman spectral parameters at 724 and 1 736 cm-1. The average of Raman peak area ratios in accordance with the abscissa, the ordinate artemisinin content for result analysis. Afterwards the results are analyzed through nonlinear regression in order to get the function between the artemisinin content and Raman peak area ratios. The quadratic function is y=0.907 22x2+0.465 93x(0<x<0.9), and its correlation coefficients is 0.992 65. In addition, measurements of artemisinin content in Chinese traditional compound medicine by Laser Raman analysis were carried out on artemisinin-piperaquine tablets. The values of artemisinin content obtained by Laser Raman spectroscopy technology and true values (14.29%) are in good agreement with each other (relative errors <10%). This research provides a fundamental analysis tool for determining artemisinin content quantitatively by using Laser Raman spectroscopy. Experiment results demonstrate that this method has the potential for obtaining artemisinin content in Chinese traditional compound medicine.
Key words：Laser Raman spectroscopy; Artemisinin content; Chinese traditional compound medicine; Quantitative analysis
李佳佳，刘靖丽，靳如意，唐于平，乐世俊，王李雯，龙 旭，张光辉，孟庆华，李荣西. 激光拉曼光谱分析中药复方制剂中青蒿素含量的研究[J]. 光谱学与光谱分析, 2019, 39(08): 2403-2408.
LI Jia-jia, LIU Jing-li, JIN Ru-yi, TANG Yu-ping, YUE Shi-jun，WANG Li-wen, LONG Xu, ZHANG Guang-hui, MENG Qing-hua, LI Rong-xi. Quantitative Measurement of Artemisinin Content in Chinese Traditional Compound Medicine by Raman Spectroscopy. SPECTROSCOPY AND SPECTRAL ANALYSIS, 2019, 39(08): 2403-2408.
