Discovery of quality control markers from traditional Chinese medicines by fingerprint-efficacy modeling: Current status and future perspectives

Dalbergia odorifera: A review of its traditional uses, phytochemistry, pharmacology, and quality control

ETHNOPHARMACOLOGICAL RELEVANCE

Dalbergia odorifera, a traditional herbal medicine, has long been used in China for dissipating blood stasis, regulating the flow of qi, and relieving pain.

AIM OF THIS REVIEW

This review aims to provide comprehensive and up-to-date information about the traditional uses, phytochemistry, pharmacology, and quality control of D. odorifera. Additionally, perspectives for possible future investigations on D. odorifera are also discussed.

MATERIALS AND METHODS

Information on D. odorifera was obtained from a library database and electronic searches (e.g., Elsevier, Springer, ScienceDirect, Wiley, Web of Science, PubMed, Google Scholar, China Knowledge Resource Integrated).

RESULTS

According to classical Chinese herbal texts and the Chinese Pharmacopoeia, D. odorifera promotes blood circulation, relieves pain, and eliminates blood stasis, and it can be used to treat cardio-cerebrovascular diseases in traditional Chinese medicine prescriptions. The chemical constituents of D. odorifera have been well studied, with approximately 175 metabolites having been identified, including flavonoids, phenols, arylbenzofurans, and quinones. The species also contains well-studied volatile oil. Its flavonoids and volatile oil are generally considered to be essential for its pharmacological activity. Modern pharmacology research has confirmed that isolated components and crude extracts of D. odorifera possess wide-ranging pharmacological effects, including anti-inflammatory, anti-angina, anti-oxidative, and other activities. Additionally, there are few quality control studies on D. odorifera.

CONCLUSIONS

To date, significant progress has been made in D. odorifera phytochemistry and pharmacology. Thus, modern pharmacological research has provided some evidence for local or traditional uses. D. odorifera also showed therapeutic potential in cardiovascular and coronary heart diseases. However, the present findings are insufficient to explain its mechanisms of action. Additionally, the mechanism of heartwood formation, artificial induction technology for heartwood production, and quality control of D. odorifera require further detailed research.

A novel critical control point and chemical marker identification method for the multi-step process control of herbal medicines via NMR spectroscopy and chemometrics

Herbal medicines have played a vital role in maintaining the health of the world population in the past thousands of years, and have proved to be an effective therapy. It is important to improve our understanding of the effects of the multi-step processing in herbal medicines on the chemical changes to ensure product quality. A proton nuclear paramagnetic resonance (¹H NMR)-based evaluation strategy was developed for an efficient process variation exploration and diversified metabolite identification. In this study, 48 process intermediates from 6 commercial batches of the multi-step manufacturing chain of Danshen processing were obtained. Hierarchical classification analysis (HCA) tree based on ¹H NMR spectra clustered the samples according to the processing steps, which indicates that ¹H NMR has the potential capability for critical control point identification based on its adequate information of the organic compounds. Then, principal component analysis (PCA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) were applied to distinguish the major metabolite differences between the intermediates before and after the critical control point. In this case, the alkali-isolation and acid-dissolution method was recognized as the most critical process in the multi-step chain of Danshen extract manufacturing. Potential metabolites with the larger amplitude of variation and contributing the most to the discrimination were found to be potential quality markers by S-plot, including several previously undetected amino acids. The results in this study are consistent with previous research studies and reference experiments conducted with other analytical tools. Taken together, they prove that ¹H NMR with chemometrics is a very effective process quality control tool to provide comprehensive information on the chemical changes during the processing of herbal medicines, and help with the identification of critical control points and potential critical quality markers.

NMR and chemometric-based critical control point and chemical marker identification for the multi-step process control of herbal medicines.

Identification of quality control markers in Suhuang antitussive capsule based on HPLC-PDA fingerprint and anti-inflammatory screening

Suhuang antitussive capsule (SH), one of traditional Chinese patent medicines, has been widely used for treating cough variant asthma and postinfectious cough in clinic. The objective of this work is to identify the characteristic and active ingredients as the quality control markers for SH based on high performance liquid chromatography with photodiode array detector (HPLC-PDA) fingerprint and screening of anti-inflammatory components. Similarity analysis (SA), hierarchical clustering analysis (HCA) and principal component analysis (PCA) were used to evaluate 16 different batches of SH. 13 compounds accounting for 36% of the total components in the fingerprint were identified and semi-quantitatively analyzed, which anti-inflammatory activity was tested with the in vitro assay. The results showed that the established chemical fingerprint could clearly distinguish different batches of SH by SA, HCA, and PCA analysis. Furthermore, four known compounds (chlorogenic acid, schisandrin, angeloylgomisin H and praeruptorin A) were screened out to be the most discriminant variables, which could be applied to quality control of SH by quantitative analysis. The semi-quantitative results showed that six compounds were major components, i.e. arctiin (10.28 ± 3.18 mg/g), ephedrine (9.26 ± 1.58 mg/g), schisandrin (3.09 ± 0.83 mg/g), pseudoephedrine (2.34 ± 1.04 mg/g), schisandrin B (1.48 ± 0.16 mg/g), and 1-caffeoylquinic acid (1.36 ± 0.42 mg/g). The anti-inflammatory results showed that SH extract, praeruptorin A, schisandrin, arctigenin and pseudoephedrine could significantly inhibit inflammatory mediator NO production in LPS-stimulated RAW264.7 macrophages. These findings indicated that praeruptorin A, schisandrin, arctiin and pseudoephedrine could be proposed as the quality control markers for SH.

Study on the spectrum-effect relationship of the xanthine oxidase inhibitory activity of Ligustrum lucidum

To evaluate the xanthine oxidase inhibitory activity of the chemical constituents of Ligustrum lucidum in vitro, the spectrum-effect relationship was investigated. The high-performance liquid chromatography fingerprint was established by ultraviolet spectrophotometry, and the xanthine oxidase inhibitory activity was tested in vitro by a high-throughput screening method. Cluster analysis, principal component analysis, gray correlation analysis, and partial least squares regression were used to explore the spectrum-effect relationships. Sixty batches of Ligustrum lucidum were collected from 16 provinces for testing. The results revealed differences among the batches of medicinal materials, and the similarity score was between 0.635 and 0.968. Thirty-three characteristic peaks (1-33) were calibrated by fingerprint evaluation software for traditional Chinese medicine. The spectrum-effect relationship study further revealed that the contents of peaks 1, 2, 4, 5, 6, 7, 14, 17, 25, 28, 31, and 33, which are potentially critical ingredients for quality control of Ligustrum lucidum fruit, were highly correlated with the inhibition of xanthine oxidase activity.

Assessing Geographical Origin of Gentiana Rigescens Using Untargeted Chromatographic Fingerprint, Data Fusion and Chemometrics

Gentiana rigescens Franchet, which is famous for its bitter properties, is a traditional drug of chronic hepatitis and important raw materials for the pharmaceutical industry in China. In the study, high-performance liquid chromatography (HPLC), coupled with diode array detector (DAD) and chemometrics, were used to investigate the chemical geographical variation of G. rigescens and to classify medicinal materials, according to their grown latitudes. The chromatographic fingerprints of 280 individuals and 840 samples from rhizomes, stems, and leaves of four different latitude areas were recorded and analyzed for tracing the geographical origin of medicinal materials. At first, HPLC fingerprints of underground and aerial parts were generated while using reversed-phase liquid chromatography. After the preliminary data exploration, two supervised pattern recognition techniques, random forest (RF) and orthogonal partial least-squares discriminant analysis (OPLS-DA), were applied to the three HPLC fingerprint data sets of rhizomes, stems, and leaves, respectively. Furthermore, fingerprint data sets of aerial and underground parts were separately processed and joined while using two data fusion strategies ("low-level" and "mid-level"). The results showed that classification models that are based OPLS-DA were more efficient than RF models. The classification models using low-level data fusion method built showed considerably good recognition and prediction abilities (the accuracy is higher than 99% and sensibility, specificity, Matthews correlation coefficient, and efficiency range from 0.95 to 1.00). Low-level data fusion strategy combined with OPLS-DA could provide the best discrimination result. In summary, this study explored the latitude variation of phytochemical of G. rigescens and developed a reliable and accurate identification method for G. rigescens that were grown at different latitudes based on untargeted HPLC fingerprint, data fusion, and chemometrics. The study results are meaningful for authentication and the quality control of Chinese medicinal materials.

Rapidly monitoring the quality of flavoring essence based on microwave-induced plasma ionization mass spectrometry and multivariate statistical analysis

Microwave-induced plasma ionization mass spectrometry (MIPI-MS) combined with multivariate statistical analysis was first applied to rapidly monitor the quality of tobacco flavoring essence. A small isolation and reaction chamber was set up between the ion source and the injection port of mass spectrometer to effectively eliminate the interference of external environment in the process of analyzing samples. The improved experimental apparatus (MIPI-MS) could achieve online and high-throughput analysis, with minimal sample preparation steps. Further, two types of tobacco flavoring essences with the similar appearance and physicochemical parameters were employed to verify the usability of the promising method in the field of quality monitoring. Firstly, the mass spectral fingerprint of each essence was established by the improved MIPI-MS method within 2 min. Then, two multivariate statistical processes were carried out to analyze mass spectral data. The similarity results indicated that the thresholds of tobacco flavoring essences from different batches were 1.512 and 2.638, respectively. The first three principal components of the established PLS-DA described 93.6% of the total variability, and provided a visualized comparison for the two types of flavoring materials. Finally, the adulterated samples were successfully distinguished by employing the two multivariate statistical processes.

Integrating chemical similarity and bioequivalence: A pilot study on quality consistency evaluation of dispensing granule and traditional decoction of Scutellariae Radix by a totality-of-the-evidence approach

There is an increasing focus on the quality consistency evaluation of dispensing granule in traditional Chinese medicines (TCMs). According to the guideline from Chinese Pharmacopoeia Commission, the substantial equivalence of dispensing granule and traditional decoction should be determined, and the chromatographic fingerprint has been recommended as a comprehensive qualitative approach to assess the quality consistency between dispensing granule and traditional decoction. However, a high-degree chemical similarity does not equal a bioequivalence. Attempting to realize the quality evaluation by integrating chemical consistency and bioequivalence, we herein proposed a totality-of-the-evidence approach based on clustering analysis and equivalence evaluation taking the dispensing granule and traditional decoction of Scutellariae Radix (SR) as a typical case. Chemical fingerprints were developed by high performance liquid chromatography coupled with photodiode array detector and quadrupole time-of-flight mass spectrometry (HPLC-PDA/QTOF-MS). Subsequently, a feature selection strategy, integrated linear and nonlinear correlation analysis, was carried out to assess the correlation between chemical profiles and biological activities. Finally, quality consistency between the dispensing granule and the traditional decoction was determined by bioactive marker-guided hierarchical clustering analysis (HCA), k-means clustering method and bioequivalence evaluation. The available evidence suggested that not all the dispensing granule of SR were sufficiently similar to the traditional decoction. This study provides an applicable methodology for quality consistency evaluation of dispensing granule and traditional decoction in TCMs.

The Screening Research of NF-κB Inhibitors from Moutan Cortex Based on Bioactivity-Integrated UPLC-Q/TOF-MS

Inflammation is a common and important pathological process, and nuclear factor-κB (NF-κB) is a key mediator of it. Moutan Cortex (MC), the dried root cortex of Paeonia suffruticosa Andr., is widely used as a remedy for the treatment of inflammatory diseases in Asian region. However, there are few studies on the systematic identification of NF-κB inhibitors of MC. In this study, the effect of inhibiting NF-κB activation of MC was assessed at the cellular level using a tumor necrosis factor-α (TNF-α) induced inflammatory model. Subsequently, ultra-performance liquid chromatography-quadrupole/time of flight-mass spectrometry (UPLC-Q/TOF-MS) combined with biological activity assay was established to screen and identify potential anti-inflammatory ingredients in MC. The results revealed that MC significantly inhibited the activation of NF-κB. Seven potential NF-κB inhibitors were screened from MC, including oxypaeoniflorin, paeoniflorin, galloylpaeoniflorin, benzoyloxypaeoniflorin, mudanpioside C, gallic acid, and paeonol. Among them, the NF-κB inhibitor activity of galloylpaeoniflorin, benzoyloxypaeoniflorin, and mudanpioside C is first reported here. In conclusion, the anti-inflammatory activity of MC was associated with the seven components mentioned above. And the bioactivity-integrated UPLC-Q/TOF which contains both chemical and bioactive details is suitable for screening active ingredients from natural medicines.