Multiple chromatographic fingerprinting and its application to the quality control of herbal medicines

Recently, chromatographic fingerprinting has become one of the most powerful approaches to quality control of herbal medicines. However, the performance of reported chromatographic fingerprinting constructed by single chromatogram sometimes turns out to be inadequate for complex herbal medicines, such as multi-herb botanical drug products. In this study, multiple chromatographic fingerprinting, which consists of more than one chromatographic fingerprint and represents the whole characteristics of chemical constitutions of the complex medicine, is proposed as a potential strategy in this complicated case. As a typical example, a binary chromatographic fingerprinting of “Danshen Dropping Pill” (DSDP), the best-sold traditional Chinese medicine in China, was developed. First, two HPLC fingerprints that, respectively, represent chemical characteristics of depsides and saponins of DSDP were developed, which were used to construct binary chromatographic fingerprints of DSDP. Moreover, the authentication and validation of the binary fingerprints were performed. Then, a data-level information fusion method was employed to capture the chemical information encoded in two chromatographic fingerprints. Based on the fusion results, the lot-to-lot consistency and frauds can be determined either using similarity measure or by chemometrics approach. The application of binary chromatographic fingerprinting to consistency assessment and frauds detection of DSDP clearly demonstrated that the proposed method was a powerful approach to quality control of complex herbal medicines.     

Development of a quality evaluation system for Panax quinquefolium. L based on HPLC chromatographic fingerprinting of seven major ginsenosides

A HPLC fingerprinting method based on the distribution and contents of seven major ginsenosides has been developed for the quality evaluation of Panax quinquefolium. L roots cultivated in China, Singapore and Canada. The method is ideally suited for the fingerprinting of P. quinquefolium. L samples or its derived products for sample authentication or quality control, e.g. pharmaceutical stability studies. Different extraction methods have been evaluated and a protocol established to maximize the gensinosides yields in routine operations. Hierarchical clustering analysis of the fingerprints demonstrates that the distribution and contents of ginsenosides in P. quinquefolium. L root vary depending on geographic location; and the quality of Jilin-cultivated P. quinquefolium. L roots is similar in composition to Canada-cultivated ones, which are generally considered among the best quality in P. quinquefolium. L.     

Chemical profiling by LC–MS/MS and HPLC fingerprint combined with chemometrics and simultaneous determination of 16 characteristic ingredients for the quality consistency evaluation of Shaoyao‐Gancao Decoction

In this paper, to evaluate the effect of the region of origin on the quality consistency of Shaoyao‐Gancao Decoction (SGD), the SGD fingerprint was developed for the first time. Chemometric methods including similarity analysis, hierarchical clustering analysis and principal component analysis were employed to study the quality consistency of SGD. Meanwhile, high‐performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight mass spectrometry was applied for comprehensive analysis of SGD and 93 compounds were tentatively characterized. Furthermore, a high‐performance liquid chromatography method with multi‐wavelength switching for simultaneous determination of 16 characteristic ingredients comprising gallic acid, oxypaeniflorin, albiflorin, paeoniflorin, liquiritin apioside, liquiritin, isoliquiritin apioside, galloylpaeoniflorin, 1,2,3,4,6‐penta‐O‐galloyl‐d ‐galactopyranose (PGG), ononin, isoliquiritin, liquiritigenin, benzoylpaeoniflorin, glycyrrhizic acid, isoliquiritigenin and formononetin, was established. All 16 analytes show excellent linearity (R² ≥ 0.9990) with recoveries ranging from 96.58 to 104.61% and limits of detection and quantification of 0.022–0.291 and 0.037–0.635 μg/mL, respectively. Finally, it was successfully applied to determine 15 batches of SGD. The results of our research indicate that different regions of origin have a significant effect on the quality consistency of SGD, and its fingerprint combined with chemometrics and multi‐ingredient determination comprise an efficient and reliable approach for quality consistency evaluation.     

Chemical fingerprinting and quantitative analysis of volatiles in <Emphasis Type="Italic">Shexiang Baoxin Pill</Emphasis> by gas chromatography with flame ionization and mass spectrometric detection

An approach to fingerprinting and the quantitative analysis of volatiles in Shexiang Baoxin Pill (SBP) was proposed by using gas chromatography (GC) with a flame ionization detector and a mass spectrometric detector (MS). Using the proposed method, the chemical fingerprint of SBP extract was established, in which the separation of more than 30 volatiles was realized in about 30 min, and 26 peaks were identified by GC/MS analysis. Seven major volatiles, including borneol, isoborneol, isopropyl methylphenol, mascone, cinnamaldehyde, cinnamic acid, and benzyl benzoate, were further quantified. The linearity, precision, stability, repeatability, and accuracy were acceptable. The proposed method was successfully applied to the determination of volatiles in 11 batches of SBP samples. To evaluate their quality, principal components analysis (PCA) was performed on the basis of the data of chemical fingerprints, and the score plot clearly revealed the variations of samples produced in different years. Moreover, the results of the quantitative analysis of various samples were also comparatively studied. The results indicated that, to ensure the quality of SBP, more efficient storage and package techniques are needed. The proposed method enables chemical fingerprinting and the simultaneous determination of multicomponents to be performed in one run, and can be applied as a comprehensive quality control technique for traditional Chinese medicine containing volatile constituents. The text was submitted by the authors in English.     

A flow-injection mass spectrometry fingerprinting method for authentication and quality assessment of Scutellaria lateriflora-based dietary supplements

Scutellaria lateriflora, commonly known as skullcap, is used as an ingredient in numerous herbal products. However, it has been occasionally adulterated/contaminated with Teucrium canadense and/or Teucrium chamaedrys, commonly known as germander, due to the morphological similarities between the two genera. The latter contains hepatotoxic diterpenes. Despite the potential hepatotoxicity introduced by germander contamination, analytical methodologies for the authentication and quality assessment of S. lateriflora-based dietary supplements have not been reported. In this study, a flow-injection/mass spectrometry fingerprinting method in combination with principal component analysis was used to survey S. lateriflora-based dietary supplements sold in the USA.     

In vitro anticomplementary activity and quality evaluation of dried blossoms of Inula nervosa Wall. from different geographical origins

Blossoms of Inula nervosa Wall. (BINW) are traditionally used as an analgesic and antitussive in China. In this study, in vitro anticomplementary activities of crude extract from BINW in 21 batches and of extracts of four monomeric compounds were evaluated by the classical pathway. The effect of the region of origin on the quality of BINW was evaluated by fingerprint analysis for the first time. Furthermore, chemometric methods including similarity analysis and principal component analysis were employed to evaluate the quality of BINW. The nine major monomeric compounds were quantitated by ultra‐high‐performance liquid chromatography. All nine analytes demonstrated excellent linearity with recoveries ranging from 97.25% to 102.76%. The limits of detection and quantification were 0.07–12.20 μg/mL and 0.22–40.27 μg/mL, respectively. Results indicate that different regions of origin have a significant effect on the quality of BINW. Fingerprint analysis in combination with chemometrics and multi‐ingredient determination is an efficient and reliable approach for quality evaluation. The BINW samples from Yunnan had the highest ratio of 1,5‐dicaffeoylquinic acid and thymol; they also exhibited significantly higher anticomplementary activity than those from three other areas. This study successfully established a rapid and efficient method to evaluate the quality and biological activity of BINW.     

Comparative chemical fingerprinting of Oroxylum indicum and Scutellaria baicalensis using liquid chromatography and mass spectrometry

Introduction: Identification of Oroxylum indicum and Scutellaria baicalensis provides an interesting challenge in selection of biomarker compound to be used in routine analysis. Both plants have similar phytochemical profile and are rich sources of flavones and flavone glycosides. The objective of this study was to prepare the chemical fingerprinting of O. indicum bark and S. baicalensis roots using the liquid chromatography and mass spectroscopy in single chromatographic method. Materials and methods: Extracts prepared using various solvent systems (methanol, aqueous methanol, chloroform, hexane, and water) of both plants were analyzed using C18 reverse phase column with solvent system containing acetonitrile and 0.1% formic acid. Major flavonoids were identified based on mass spectra, fragmentation pattern, and UV spectra. Results: In this article, well-resolved high-performance liquid chromatographic (HPLC) separation in both plant extracts was obtained and chemical fingerprints for both plant extracts were established and flavonoids present (baicalin, oroxylin A-7-O-glucuronide, chrysin-7-O-glucuronide, baicalein, chrysin, oroxylin-A, wogonin, skullcap flavone II) were identified as possible biomarkers. Conclusion: Mass spectrometry coupled with HPLC can be a tool for fingerprinting of various natural products used in dietary supplement industry. The fingerprint developed in the article can be used for quality evaluation as well as identifying possible adulteration of extracts of both the plants.     

Multi-components determination by single reference standard and HPLC fingerprint analysis for Lamiophlomis rotata Pill

A validated HPLC method was developed to evaluate the quality of Lamiophlomis rotata Pill combining the multi-components analysis by single reference standard with HPLC fingerprint analysis. Five bioactive components (shanzhiside methyl ester, loganin, 8-O-acetylshanzhiside methyl ester, forsythoside B and luteolin-7-O-β-D-glucopyranoside) were selected as markers to control the quality of L. rotata Pill. The results revealed that the chromatographic fingerprint method coupled with multi-components analysis provides an effective and feasible way to determine the components in L. rotata Pill.     

Quantitative and fingerprinting analysis of Atractylodes rhizome based on gas chromatography with flame ionization detection combined with chemometrics

This study assessed the feasibility of gas chromatography with flame ionization detection fingerprinting combined with chemometrics for quality analysis of Atractylodes rhizome. We extracted essential oils from 20 Atractylodes lancea and Atractylodes koreana samples by hydrodistillation. The variation in extraction yields (1.33–4.06%) suggested that contents of the essential oils differed between species. The volatile components (atractylon, atractydin, and atractylenolide I, II, and III) were quantified by gas chromatography with flame ionization detection and confirmed by gas chromatography with mass spectrometry, and the results demonstrated that the number and content of volatile components differed between A. lancea and A. koreana. We then calculated the relative peak areas of common components and similarities of samples by comparing the chromatograms of A. lancea and A. koreana extracts. Also, we employed several chemometric techniques, including similarity analysis, hierarchical clustering analysis, principal component analysis, and partial least‐squares discriminate analysis, to analyze the samples. Results were consistent across analytical methods and showed that samples could be separated according to species. Five volatile components in the essential oils were quantified to further validate the results of the multivariate statistical analysis. The method is simple, stable, accurate, and reproducible. Our results provide a foundation for quality control analysis of A. lancea and A. koreana.     

Chemometrics and modernization of traditional Chinese medicine

Development of chromatographic fingerprinting and its related chemometric methods in the research of quality control of traditional Chinese medicines(TCMs) are discussed. The quality control methods for guarantying the authentication and stability of products and semi-products of TCMs are firstly assessed. The technique based on chromatographic fingerprinting is essentially a kind of high-through put and integral tools to explore the complexity of herbal medicines. In order to further control the comprehensive quality of TCMs,confirmation and identification of their important chemical components are necessary. Some new strategies are proposed to trace the chemical changes of chromatographic fingerprints both in product processing and/or after their administration by modern chromatographic techniques and chemometrics. Combined with systems biology and bioinformatics,it seems possible for one to reveal the working mechanism of TCMs and to further control their intrinsic quality comprehensively.     

Quality control method for commercially available wild Jujube leaf tea based on HPLC characteristic fingerprint analysis of flavonoid compounds

Flavonoids are the main active components of natural medicinal plants with many physiological functions. In this study, an HPLC fingerprinting method based on the distribution and relative amount of 11 bioactive flavonoids was established for the quality evaluation of commercially available wild Jujube leaf tea (JLT) from China. Separation of the crude flavonoid extract was achieved on a column filled with C₁₈ material with a high carbon content. The flavonoids in wild JLT were identified based on UV spectroscopy and accurate mass measurements by TOF‐MS. Twenty‐one batches of practical samples collected from different habitats were analyzed by using the developed HPLC method to construct the HPLC characteristic fingerprint of wild JLT. Then, combined with clustering and similarity analyses, the HPLC characteristic fingerprint was used for the authentication and quality evaluation of commercial wild JLT. Results indicated that the proposed HPLC characteristic fingerprint reflected the inherent characteristics of wild JLT collected from different regions. Authenticity identification and quality control of commercially available wild Jujube tea were achieved based on the HPLC characteristic fingerprint analysis. This new approach to bioactive component profiling provided a promising reference method for the quality evaluation of commercial wild flower and plant tea.     

Quality consistency evaluation of commercial transfer factor injections by chromatographic fingerprint combined with multivariate statistical analysis

The current quality control methods relying mainly on chromogenic reaction can hardly ensure the quality and safety of the biochemical drug with complex chemical composition. Therefore, a chromatographic fingerprint method was developed for the quality evaluation of a multicomponent biochemical drug, transfer factor injection. High‐performance liquid chromatography fingerprint was measured by using a C₁₈ column (250 × 4.6 mm, 5 µm) with a mobile phase composed of 0.1% trifluoroacetic acid–water and 0.085% trifluoroacetic acid–acetonitrile under gradient elution. The developed method was validated and was subsequently applied to 57 batches of commercial products which were sampled by National Drug Assessment Program. High‐resolution mass spectrometry analysis was performed on characteristic peaks of fingerprints, and a series of amino acids, nucleosides, and deoxynucleosides were identified. In the fingerprint assessments, principal component analysis and Hotelling T² analysis yielded the best results. The results generally indicated that there was a significant difference among products of batch‐to‐batch or from different manufacturers. Abnormal samples and its discriminatory components were also explored. In summary, the established fingerprinting method with multivariate statistical analysis could offer an efficient, reliable, and practical approach for quality consistency evaluation of transfer factor injection, providing a reference for the quality control of other multicomponent biochemical drugs.     

UHPLC–MS/MS quantification combined with chemometrics for the comparative analysis of different batches of raw and wine‐processed Dipsacus asper

A rapid and sensitive ultra‐high performance liquid chromatography with tandem mass spectrometry approach was established for the simultaneous determination of 4‐caffeoylquinic acid, loganic acid, chlorogenic acid, loganin, 3,5‐dicaffeoylquinic acid, dipsacoside B, asperosaponin VI, and sweroside in raw and wine‐processed Dipsacus asper . Chloramphenicol and glycyrrhetinic acid were employed as internal standards. The proposed approach was fully validated in terms of linearity, sensitivity, precision, repeatability as well as recovery. Intra‐ and interassay variability for all analytes were 2.8–4.9 and 1.7–4.8%, respectively. The standard addition method determined recovery rates for each analytes (96.8–104.6%). In addition, the developed approach was applied to 20 batches of raw and wine‐processed samples of Dipsacus asper . Principle component analysis and partial least squares‐discriminate analysis revealed a clear separation between the raw group and wine‐processed group. After wine‐processing, the contents of loganic acid, chlorogenic acid, dipsacoside B, and asperosaponin VI were upregulated, while the contents of 3,5‐dicaffeoylquinic acid, 4‐caffeoylquinic acid, loganin, and sweroside were downregulated. Our results demonstrated that ultra‐high performance liquid chromatography with tandem mass spectrometry quantification combined with chemometrics is a viable method for quality evaluation of the raw Dipsacus asper and its wine‐processed products.     

Metabolite Fingerprinting Using 1H-NMR Spectroscopy and Chemometrics for Classification of Three Curcuma Species from Different Origins

Curcuma longa, Curcuma xanthorrhiza, and Curcuma manga have been widely used for herbal or traditional medicine purposes. It was reported that turmeric plants provided several biological activities such as antioxidant, anti-inflammatory, hepatoprotector, cardioprotector, and anticancer activities. Authentication of the Curcuma species is important to ensure its authenticity and to avoid adulteration practices. Plants from different origins will have different metabolite compositions because metabolites are affected by soil nutrition, climate, temperature, and humidity. ¹H-NMR spectroscopy, principal component analysis (PCA), and orthogonal projections to latent structures-discriminant analysis (OPLS-DA) were used for authentication of C. longa, C. xanthorrhiza, and C. manga from seven different origins in Indonesia. From the ¹H-NMR analysis it was obtained that 14 metabolites were responsible for generating classification model such as curcumin, demethoxycurcumin, alanine, methionine, threonine, lysine, alpha-glucose, beta-glucose, sucrose, alpha-fructose, beta-fructose, fumaric acid, tyrosine, and formate. Both PCA and OPLS-DA model demonstrated goodness of fit (R² value more than 0.8) and good predictivity (Q² value more than 0.45). All OPLS-DA models were validated by assessing the permutation test results with high value of original R² and Q². It can be concluded that metabolite fingerprinting using ¹H-NMR spectroscopy and chemometrics provide a powerful tool for authentication of herbal and medicinal plants.     

Rapidly differentiating grape seeds from different sources based on characteristic fingerprints using direct analysis in real time coupled with time‐of‐flight mass spectrometry combined with chemometrics

The seeds of grapevine (Vitis vinifera) are a byproduct of wine production. To examine the potential value of grape seeds, grape seeds from seven sources were subjected to fingerprinting using direct analysis in real time coupled with time‐of‐flight mass spectrometry combined with chemometrics. Firstly, we listed all reported components (56 components) from grape seeds and calculated the precise m/z values of the deprotonated ions [M–H]^–. Secondly, the experimental conditions were systematically optimized based on the peak areas of total ion chromatograms of the samples. Thirdly, the seven grape seed samples were examined using the optimized method. Information about 20 grape seed components was utilized to represent characteristic fingerprints. Finally, hierarchical clustering analysis and principal component analysis were performed to analyze the data. Grape seeds from seven different sources were classified into two clusters; hierarchical clustering analysis and principal component analysis yielded similar results. The results of this study lay the foundation for appropriate utilization and exploitation of grape seed samples. Due to the absence of complicated sample preparation methods and chromatographic separation, the method developed in this study represents one of the simplest and least time‐consuming methods for grape seed fingerprinting.     

Chromatographic fingerprinting and related chemometric techniques for quality control of traditional Chinese medicines

Development of chromatographic fingerprint (CF) and related chemometric methods and their applications to quality control of traditional Chinese medicines (TCMs) were discussed. CF is essentially a kind of quality control method for TCMs (or Chinese herbal medicines). Also, it is a quality‐relevant‐data high‐throughput and integral tool to explore chemically the complexity of TCMs. With the help of chemometrics, some difficulties in evaluation and analysis of CFs, such as calculation of information content, peak alignment, pattern analysis, deconvolution of overlapping peaks, etc. could be well solved. To further explore TCMs synergic quality, intensive study of CF coupled with chemometrics will create the possibility to achieve the aim to reveal the working mechanisms of TCMs and to further control and strengthen TCMs' intrinsic quality in a comprehensive manner.     

The chemical profile of active fraction of Kalimeris indica and its quantitative analysis

Kalimeris indica (L) Sch-Bip is a medicinal plant used by the Miao ethnic group in the Guizhou province of China. It is widely used as a fresh vegetable to treat colds, diarrhea and gastric ulcers. However, few studies have been conducted on the mechanism of its effect on colds, and its quality control. The anticomplement and antitussive activities of different polar extracts of K. indica were evaluated. Fifty-nine compounds, mainly including phenols and flavonoids, were identified in K. indica extract by ultra-high-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry. A method was established through ultra-high-performance liquid chromatography with a photodiode array to simultaneously determine the anticomplement and antitussive activity of five compounds in K. indica combining chemical identification with chemometrics for discrimination and quality assessment. Also, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid exhibited significantly higher anticomplementary activity than the other three compounds. The quantitative data were further analyzed by principal component analysis and orthogonal partial least-squares discriminant analysis. Heatmap visualization was conducted to clarify the distribution of the major compounds in different geographical origins. Screening pharmacological activities by a combination of chemometrics and chemical identification might be an effective method for the quality control of K. indica.     

Differentiating Westlake Longjing tea from the first‐ and second‐grade producing regions using ultra high performance liquid chromatography with quadrupole time‐of‐flight mass spectrometry‐based untargeted metabolomics in combination with chemometrics

There are numerous articles published for geographical discrimination of tea. However, few research works focused on the authentication and traceability of Westlake Longjing green tea from the first‐ and second‐grade producing regions because the tea trees are planted in a limited growing zone with identical cultivate condition. In this work, a comprehensive analytical strategy was proposed by ultrahigh performance liquid chromatography‐quadrupole time‐of‐flight mass spectrometry‐based untargeted metabolomics coupled with chemometrics. The automatic untargeted data analysis strategy was introduced to screen metabolites that expressed significantly among different regions. Chromatographic features of metabolites can be automatically and efficiently extracted and registered. Meanwhile, those that were valuable for geographical origin discrimination were screened based on statistical analysis and contents in samples. Metabolite identification was performed based on high‐resolution mass values and tandem mass spectra of screened peaks. Twenty metabolites were identified, based on which the two‐way encoding partial least squares discrimination analysis was built for geographical origin prediction. Monte Caro simulation results indicated that prediction accuracy was up to 99%. Our strategy can be applicable for practical applications in the quality control of Westlake Longjing green tea.     

Assessment of Polygonum capitatum Buch.‐Ham. ex D.Don by metabolomics based on gas chromatography with mass spectrometry

Polygonum capitatum is widely used in southwest China. It has considerable therapeutic efficacy for urinary tract infections. P. capitatum contains multiple components and quality assessment can be achieved by means of metabolic fingerprinting. In this paper, a new strategy for P. capitatum quality determination was developed. Eleven batches of P. capitatum were collected from five geographical areas in China including a standard batch regulated by Good Agriculture Practice. Gas chromatography with mass spectrometry was used to generate fingerprints from triplicate extractions to each batch (n = 33). Hierarchical clustering analysis was applied to assess similarities among the ten batches to the standard batches. Orthogonal projection to latent structures discriminate analysis, cross‐validated with permutation tests, was performed to investigate discriminating metabolites. Results demonstrated that the overall evaluation hierarchical clustering analysis clustered two batches with distance > 3. Orthogonal projection to latent structures discriminate analysis (R²Y (cum) = 0.997, Q² (cum) = 0.97, CV‐ANOVA = 8.48 × 10^?11) indicated that several sugars contributed to batch classification. This method is a rational approach that can classify against a regulated plant standard and distinguishes samples from different origins or processing time in a holistic manner and metabolites driving any differences can be easily identified.