Discovery of discriminatory quality control markers for Chinese herbal medicines and related processed products by combination of chromatographic analysis and chemometrics methods: Radix Scutellariae as a case study
Graphical abstract
Introduction
Chinese herbal medicines (CHMs) are attracting intensive attention due to their long historical applications and reliable therapeutic efficacy. Unlike western herbs, many CHMs are usually subjected to a processing procedure. The herb-processing method, which is based on the dialectical treatments of medical needs and the drugs' characteristics, has been assisting CHMs in exerting reasonable pharmacological effects [1], [2]. There are various traditional ways of processing herbs, such as steaming, stir-frying, baking, and braising, etc. These processes contribute to moderating drastic action, enhancing efficacy, increasing potency and/or relieving toxicity [3].
Although CHMs and their related processed products are derived from the same herbal origin, their pharmacological effects and clinical applications varied greatly from each other [4]. The altered effects have been ascribed to the changed chemical profiles between crude herb and the processing-treated herbs [5], [6]. Therefore, for the purpose of precision quality evaluation of crude herb and processed products, discovery of discriminatory quality control markers is very important for their safe and effective use [7]. However, in most cases, the crude herb and processed products share the same quality specification, mainly due to lack of deep understanding of chemical changes during processing treatment [2], [8].
Radix Scutellariae (RS), derived from the roots of Scutellaria baicalensis Georgi (Family Labiatae), is a famous herbal medicine used in China with the Chinese name of ‘Huangqin’. It has been used for the treatment of various ailments including fevers, diarrhea, ulcers, cancers, and various inflammatory diseases [9], [10], [11], [12]. According to the processing theory of CHMs, RS is traditionally converted into wine-processed RS and carbonized RS. Previous studies had proved that the wine-processed RS was more effective in cleaning the lung fire, the upper-energizer heat and humidity with the aid of wine characteristic [13], [14], and carbonized RS could enhance the effect of hemostatic after carbonization [15]. Phytochemical and pharmacological investigations revealed that the flavonoids such as baicalin, wogonoside, baicalein and wogonin in RS were responsible for the curative effects [16]. Unfortunately, the exact difference of chemical composition in crude and processed RS is not yet clear. In Chinese Pharmacopoeia (2015 Version) [17], the content of baicalin (not less than 8%) is officially set as acceptance criterion for both crude and wine-processed RS, which may not be specific and meaningful.
In this work, a comprehensive strategy integrating chromatographic analysis and chemometrics was firstly proposed to identify quality control markers for crude RS and its related processed products. Firstly, the common peaks from chromatographic fingerprint of 49 batches of crude and processed RS samples were comprehensively characterized by a high-performance liquid chromatography combined with photodiode array detector (HPLC-PAD) and quadrupole time-of-flight mass spectrometry (QTOF-MS) method. Secondly, the principal discriminatory markers of the crude and processed products were discovered by back propagation-artificial neural network (BP-ANN) model. Thirdly, a single standard to determine multi-components (SSDMC) method was developed for quantitative analysis of the selected markers in crude RS, wine-processed RS and carbonized RS. Subsequently, the quantitative data were subjected to principal component analysis (PCA) and partial least-squares discriminant analysis (PLS-DA), followed by support vector machine (SVM) modelling. Finally, the distribution of identified flavonoids in the three different RS products was analyzed by a hotmap visualization, and three content-specific specifications were accordingly suggested.
Section snippets
Materials and reagents
Twenty-five batches of crude RS were collected from cultivated or commercial sources in China and authenticated by Professor Hui-Jun Li from Department of Pharmacognosy in China Pharmaceutical University. Twelve batches of wine-processed RS were processed according to Chinese Pharmacopoeia (2015 Version). Briefly, the crude RS slices were mixed with Chinese rice wine (100:12.5, drug/wine, w/w), then the moistened slices were stir-fried in a metallic pan at 120–140 °C over a low flame until
Optimization of extraction method and chromatographic conditions
To ensure satisfactory extraction efficiency, variables including extraction method, solvent and extraction time were optimized. 40% methanol, 70% methanol, 100% methanol and ethanol were tested as extraction solvents. Results showed that 70% methanol produced a desirable extraction efficiency for flavonoids. Different extraction methods including sonication, reflux and soak at room temperature were tested. Sonication was chosen as the extraction method for the high efficiency and convenience
Conclusion
The processing procedure confers upon traditional CHMs different but valuable therapic effects. Along with the demand of CHMs for medical care and dietary supplement increases, the quality control of CHMs and their related products has become a critical issue. Based on chromatographic fingerprint analysis and BP-ANN model, baicalein, wogonoside, baicalin and wogonin, the four principal discriminatory compounds were determined as the quality control markers of RS and its related products. The
Acknowledgements
This work was supported by the National Natural Science Foundation of China (No. 81322051), the Natural Science Foundation of Jiangsu Province (No. BK20151442) and the Project Funded by the Priority Academic Program Development (PAPD) of Jiangsu Higher Education Institutions.
References (29)
- et al.
Global metabolite profiling and diagnostic ion filtering strategy by LC-QTOF MS for rapid identification of raw and processed pieces of Rheum palmatum L
Food Chem.
(2016) - et al.
The effects of wine-processing on ascending and descending: the distribution of flavonoids in rat tissues after oral administration of crude and wine-processed Radix scutellariae
J. Ethnopharmacol.
(2014) - et al.
Thermal effects on the dissolution enhancement of Radix scutellariae by wine-processing
Appl. Therm. Eng.
(2016) - et al.
Urine metabolomics study on the liver injury in rats induced by raw and processed Polygonum multiflorum integrated with pattern recognition and pathways analysis
J. Ethnopharmacol.
(2016) - et al.
Steamed ginger (Zingiber officinale): changed chemical profile and increased anticancer potential
Food Chem.
(2011) - et al.
Simultaneous determination of baicalin wogonoside, baicalein, wogonin, oroxylin A and chrysin of Radix scutellariae extract in rat plasma by liquid chromatography tandem mass spectrometry
J. Pharm. Biomed. Anal.
(2012) - et al.
Screening active compounds acting on the epidermal growth factor receptor from Radix scutellariae via cell membrane chromatography online coupled with HPLC/MS
J. Pharm. Biomed. Anal.
(2012) - et al.
Oral pharmacokinetics of baicalin, wogonoside, oroxylin A 7-O-β-D-glucuronide and their aglycones from an aqueous extract of Scutellariae Radix in the rat
J. Chromatogr. B
(2016) - et al.
Development of a SPE-LC/MS/MS method for simultaneous quantification of baicalein wogonin, oroxylin A and their glucuronides baicalin, wogonoside and oroxyloside in rats and its application to brain uptake and plasma pharmacokinetic studies
J. Pharm. Biomed. Anal.
(2014) - et al.
A targeted strategy to analyze untargeted mass spectral data: rapid chemical profiling of Scutellaria baicalensis using ultra-high performance liquid chromatography coupled with hybrid quadrupole orbitrap mass spectrometry and key ion filtering
J. Chromatogr. A
(2016)
One single standard substance for the determination of multiple anthraquinone derivatives in rhubarb using high-performance liquid chromatography-diode array detection
J. Chromatogr. A
UPLC-Q-TOF/MS-based screening and identification of the main flavonoids and their metabolites in rat bile, urine and feces after oral administration of Scutellaria baicalensis extract
J. Ethnopharmacol.
Depletion of high-abundance flavonoids by metal complexation and identification of low-abundance flavonoids in Scutellaria baicalensis Georgi
J. Chromatogr. A
Identification and quantification of baicalein wogonin, oroxylin A and their major glucuronide conjugated metabolites in rat plasma after oral administration of Radix scutellariae product
J. Pharm. Biomed. Anal.
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These authors contributed equally to this work.