Research Progress And Application in Fingerprint Technology On Chinese Materia Medica

Abstract: Chinese materia medica (CMM) fingerprint technology is an effective method to evaluate pros and cons, identify the authenticity, distinguish species, and ensure consistency and stability of CMM. With the development of modern analytical technology, CMM fingerprint technology is widely used and approved in the study of effective components, quality control, and identification of Chinese medicine. The related references of biological fingerprints of CMM and chemical fingerprints of CMM (including IR, UV, NMR, electro-chemical method, TLC, HPLC, GC, and CEP) and data calculation methods in the three years have been summarized in this article. Meanwhile, the direction and prospect of the CMM fingerprint technology are discussed. 

Keywords: Chinese materia medica; fingerprint; effective component; quality control; identification of Chinese materia medica

TCM CISTANCHE HERBAL HPLC TEST REPORTS 

Supportive Service Of Wecistanche

Email:wallence.suen@wecistanche.com 

Whatsapp/Tel:+86 15292862950

Over the past few decades, the demand for traditional Chinese medicine (TCM) and its preparations has grown rapidly around the world, and it has become increasingly urgent to evaluate and ensure their quality. Since TCM contains a large number of complex chemical components, it is difficult to fully characterize all compounds, and these compounds usually have synergistic effects in treatment, so the quality control of TCM is much more difficult than that of synthetic chemical drugs. Therefore, it is very necessary to ensure the quality of TCM and its preparations [1]. TCM fingerprint technology is an effective method to evaluate the quality of TCM, identify its authenticity, distinguish species, and ensure its consistency and stability. TCM fingerprints are divided into chemical fingerprints and biological fingerprints. Chemical fingerprints are spectra or chromatograms obtained by measuring the various chemical components of TCM. The corresponding analytical techniques include infrared spectroscopy, ultraviolet spectroscopy, nuclear magnetic resonance spectroscopy, electrochemical method, thin layer chromatography, high-performance liquid chromatography, gas chromatography, capillary electrophoresis, etc. [2]; biological fingerprints are mainly used to identify the authenticity of gene fragments of TCM. 

This paper mainly summarizes the relevant literature on traditional Chinese medicine fingerprint and data calculation methods in the past three years and discusses its development direction and prospects.

1 Chemical fingerprint

1.1 Spectral fingerprint

1.1.1 Infrared spectroscopy

Infrared spectroscopy uses the infrared absorption frequency of molecular functional groups in compounds to analyze samples. This analytical method requires flexible sampling methods and has the advantages of being fast, simple, and low in testing costs [3]. However, infrared spectroscopy shows the spectrum of mixed chemical components of traditional Chinese medicine, and infrared spectra are additive, so this method cannot be used as a quantitative analysis method. It has little specificity for traditional Chinese medicines with complex components. It is currently used to identify the authenticity of traditional Chinese medicines such as toad oil, coptis root, pearls, and compound preparations.

Wang et al. [4] used Fourier transform infrared spectroscopy (FT-IR) combined with second derivative infrared spectroscopy (SD-IR) and two-dimensional correlation infrared spectroscopy (2D-IR) to develop a multi-step infrared macro-fingerprint based on base peak matching technology and spectral correlation coefficient to monitor the changes of flavonoids, saponins, sugars, glycyrrhizin and ammonium glycyrrhizinate during the separation of the chemical components of Glycyrrhiza uralensis Fisch. This method can quickly and comprehensively reveal the changes of various chemical components during the separation of licorice. Ma et al. [5] established the FT-IR and 2D-IR fingerprint of Panaxnotogeinseng (Burk.) F. H. Chen, which can quickly identify three types of Panax notoginseng: 20T, 60T, and 120T. This method can be used to identify easily confused traditional Chinese medicines. Chen Long et al. [6] used near infrared spectroscopy combined with X-ray diffraction and EDTA titration to analyze eight kinds of carbonate-containing mineral Chinese medicines, including Nanhanshui stone, stalactite, stone swallow, stone crab, stone flower, calamine, fish brain stone, and goose pipe stone. The results showed that the characteristic spectral bands of carbonates were 6070-5000 cm-1 and 4800-4050 cm-1, among which the peak of calcium carbonate was determined to be 4275 cm-1. This method provides new ideas and methods for the identification and quality control of mineral Chinese medicines. Xu et al. [7] used FT-IR combined with SD-IR and 2D-IR to establish a multi-step infrared macroscopic fingerprint analysis of Coptis chinensis Franch. By comparing the peak intensities of its common peaks and variant peaks, various processed products and different extracts of Coptis chinensis can be quickly identified and distinguished.

Yang Wenzhe et al. [8] used near-infrared spectroscopy combined with principal component analysis (PCA) to analyze five marine shellfish Chinese medicinal pieces: oyster Ostrea rivularis Gould, stone cassia osmanthus Haliotis diversicolor Reeve, mother-of-pearl Hyriopsis cumingii (Lea), clamshell Cyclina sinensis (Gmelin), and Arca subcrenata Lischke. The results showed that this method could distinguish oysters, stone cassia osmanthus, and mother-of-pearl very well. Since the relationship and shell structure of the corrugated clamshell were similar, it could not be distinguished, but these two medicinal materials were clearly distinguished from the other three medicinal materials. Yan et al. [9] used FT-IR combined with SD-IR and 2D-IR to perform infrared spectroscopy identification on Lonicera Japonica and Flos Lonicerae Confusae. The results showed that there were obvious differences between the two at 1 078, 1 050, 988, 923, 855, 815, and 781 cm−1. This method can be used as an effective technology for identifying the authenticity of Lonicera Japonica.

1.1.2 Ultraviolet spectroscopy

Ultraviolet spectroscopy is a spectrum generated by the transition of valence electrons in molecules. It relies on the position of the absorption peak on the spectrum and the absorption intensity of the absorption spectrum to analyze and identify samples. It has the characteristics of strong practicality, reliable sensitivity, no pollution, and good reproducibility [10]. However, this method also has limitations. Since it can only provide information on the absorption peaks of chemical components, it cannot fully reflect the changes in chemical components in Chinese medicinal materials, nor can it accurately quantify Chinese medicinal materials. In addition, its quantitative error is mainly caused by the overlap of absorption peaks of coexisting substances.

Huang Tao et al. [11] established ultraviolet fingerprints of chloroform, petroleum ether, water and anhydrous ethanol extracts of Pinellia ternata (Thunb.) Breit., respectively. By using the dual index sequence analysis method, by comparing the variation peak rate and common peak rate of the spectrum, it can accurately identify Pinellia samples from 19 different origins. Zhong Gui et al. [12] used UV fingerprinting combined with partial least variance discriminant analysis (PLS-DA) to identify Panax japonicas C. A. Mey.var. major (Burk.) C. Y. Wu et K. M. Feng from different origins. The analysis results showed that although the absorption wavelengths of the characteristic absorption peaks of Panax japonicas from different origins were similar, the peak intensities were different. The peak intensity can be effectively used to distinguish Panax japonicas from different origins. Zuo Xu et al. [13] compared the similarity value of UV fingerprints with the threshold in the experiment of blending buckwheat flour Fagopyrum tataricum (L.) Gaertn. The results showed that when the threshold of buckwheat flour was less than 95%, the similarity value would change significantly. It is a convenient, low-cost and fast method to identify the quality stability of buckwheat flour.

1.1.3 Nuclear Magnetic Resonance Spectroscopy

Nuclear magnetic resonance spectroscopy is a spectrum produced by the energy level transition of a specific atomic nucleus when it absorbs radio frequency radiation energy in a magnetic field. Nuclear magnetic resonance spectroscopy is characterized by singleness, comprehensiveness, characteristics and quantitativeness. Under standard extraction and separation methods, there is an accurate correspondence between nuclear magnetic resonance spectra and plant species, and it is not easy to confuse them [14]. This method determines the structure of relevant chemical components in traditional Chinese medicine by obtaining parameters such as proton or carbon chemical shift, number of resonance peaks, and relative intensity from 1H-NMR or 13C-NMR spectra, and is generally applicable in the analysis and identification of traditional Chinese medicine.

Farag et al. [15] used 1D and 2D nuclear magnetic resonance technology to establish the fingerprint of the crude extract of Balanites aegyptiaca (L.) Del., and successfully identified fenugreek alkaloids (which have obvious hypoglycemic effects) for the first time, which may provide a new option for the treatment of diabetes. Huang Tao et al. [16] established the 1H-NMR fingerprint of Eucommia ulmoides Oilv., and used NMR titration and JRES two-dimensional NMR spectroscopy to label the five active products contained in it, namely chlorogenic acid, kaempferol, terrestrin, quercetin, and astragaloside, providing a new means for the quality control of Eucommia ulmoides. Petrakis et al. [17] conducted NMR hydrogen spectrum analysis on Crocus sativus L. and a mixed sample of Crocus sativus L. adulterated with 20% of Crocus stamens, safflower, turmeric, and gardenia, and established a 1H-NMR fingerprint. PCA, orthogonal partial least squares discriminant analysis (OPLS-DA), and O2PLS-DA were used to clearly observe that the similarity between genuine saffron and adulterated saffron was very low. This method can be used as an effective technology to distinguish the quality of saffron. Qu Tingli et al. [18] used nuclear magnetic resonance technology to establish the 1H-NMR fingerprint of Astragalus injection and identified 25 primary and secondary metabolites contained in Astragalus injection. Combined with relative content and similarity analysis, the chemical composition of 8 batches of Astragalus injection was identified, which can be used as a quality evaluation standard for Astragalus injection.