Discovery and identification of interspecies peptide biomarkers in the seahorse species using liquid chromatography tandem mass spectrometry and chemometrics.

Seahorses have important edible and medicinal values including strengthening the body, tonifying the liver and kidneys, and reducing swelling. And there are abundant seahorse species on Earth. Many seahorses have large price differences due to the scarcity of resources, and some seahorses with similar appearances appear to be confused for use. While in market trading, Hippocampus is susceptible to loss of specialized morphology characteristics, making it difficult to distinguish between specific species. Here we report an effective method based on peptide biomarkers for the identification of seahorse species. Peptide biomarkers for each species were predicted using nano-liquid chromatography-tandem mass spectrometry (Nano-LC-MS/MS) combined with chemometrics software. One unique biomarker peptide for each species was synthesized and verified, and finally developed a liquid chromatography tandem mass spectrometry (LC-MS/MS) multiple reaction monitoring method. The results indicate that the method has great potential for species-specific identification of seahorses and their preparations, among others.

A quality-comprehensive-evaluation-index-based model for evaluating traditional Chinese medicine quality.

BACKGROUND: Evaluating traditional Chinese medicine (TCM) quality is a powerful method to ensure TCM safety. TCM quality evaluation methods primarily include characterization evaluations and separate physical, chemical, and biological evaluations; however, these approaches have limitations. Nevertheless, researchers have recently integrated evaluation methods, advancing the emergence of frontier research tools, such as TCM quality markers (Q-markers). These studies are largely based on biological activity, with weak correlations between the quality indices and quality. However, these TCM quality indices focus on the individual efficacies of single bioactive components and, therefore, do not accurately represent the TCM quality. Conventionally, provenance, place of origin, preparation, and processing are the key attributes influencing TCM quality. In this study, we identified TCM-attribute-based quality indices and developed a comprehensive multiweighted multi-index-based TCM quality composite evaluation index (QCEI) for grading TCM quality. METHODS: The area of origin, number of growth years, and harvest season are considered key TCM quality attributes. In this study, licorice was the model TCM to investigate the quality indicators associated with key factors that are considered to influence TCM quality using multivariate statistical analysis, identify biological-evaluation-based pharmacological activity indicators by network pharmacology, establish real quality indicators, and develop a QCEI-based model for grading TCM quality using a machine learning model. Finally, to determine whether different licorice quality grades differently reduced the inflammatory response, TNF-α and IL-1ß levels were measured in RAW 264.7 cells using ELISA analysis. RESULTS: The 21 quality indices are suitable candidates for establishing a method for grading licorice quality. A computer model was established using SVM analysis to predict the TCM quality composite evaluation index (TCM QCEI). The tenfold cross validation accuracy was 90.26%. Licorice diameter; total flavonoid content; similarities of HPLC chromatogram fingerprints recorded at 250 and 330 nm; contents of liquiritin apioside, liquiritin, glycyrrhizic acid, and liquiritigenin; and pharmacological activity quality index were identified as the key indices for constructing the model for evaluating licorice quality and determining which model contribution rates were proportionally weighted in the model. The ELISA analysis results preliminarily suggest that the inflammatory responses were likely better reduced by premium-grade than by first-class licorice. CONCLUSIONS: In the present study, traditional sensory characterization and modern standardized processes based on production process and pharmacological efficacy evaluation were integrated for use in the assessment of TCM quality. Multidimensional quality evaluation indices were integrated with a machine learning model to identify key quality indices and their corresponding weight coefficients, to establish a multiweighted multi-index and comprehensive quality index, and to construct a QCEI-based model for grading TCM quality. Our results could facilitate and guide the development of TCM quality control research.

Discovery of species-specific peptide markers and development of quality-evaluation strategies for deer horn gelatin using liquid chromatography-tandem mass spectrometry and a label-free methodology.

Deer horn gelatin (DHG) is a valuable nutritional dietary supplement. Due to the significant variation in the price of DHG from different sources, it is important to assess its quality and to clarify the species of its raw material. However, due to the similarity in appearance and physicochemical properties, as well as the destruction of genetic material during the manufacturing process, it is difficult to distinguish DHG from gelatin derived from other sources. Furthermore, current methods are unable to evaluate the overall quality of DHG. Using Nano LC-Orbitrap MS and data analysis software, DHG samples from five deer species were analyzed to identify peptide markers specific to alpha-2-HS-glycoprotein (AHSG) and collagen. The peptide markers were validated using HPLC-Triple Quadrupole MS, and strategies for assessing the quality of DHG were developed. Eighteen peptide markers were discovered, comprising peptides with differing specificities. Three strategies for the identification, characteristic mapping, and content determination of DHG were developed. These strategies can be used to assess the quality of deer gelatin.

Identification of Pulsatilla chinensis (Bge.) Regel and look-alike species by UHPLC-TOF-MS using multivariate statistical analysis.

Pulsatillae Radix, the root of Pulsatilla chinensis (Bge.) Regel, is recorded in the Pharmacopoeia of the People's Republic of China and has been widely used for its pharmacological activities, such as anti-inflammatory, antioxidant, antibacterial, antitumor, and cardiovascular benefits. However, there are several look-alike species that can be marketed as Pulsatillae Radix. To distinguish P. chinensis (Bge.) Regel from its look-alikes, viz. Pulsatilla cernua (Thunb.) Bercht et Opiz., Pulsatilla dahurica (Fisch.) Spreng., Anemone tomeutosa (Maxim.) Pei., and Rhaponticum uniflorum (L.) DC, we used ultra high performance liquid chromatography with time-of-flight mass spectrometry combined with principal component analysis to compare their chemical compositions. Four ions, a (RT 8.98 min, m/z 1381.6671), b (RT 10.64 min, m/z 1219.6143), c (RT 11.52 min, m/z 1217.5978), and d (RT 13.6 min, m/z 749.4463), from P. chinensis (Bge.) Regel were identified as potential chemical markers to distinguish it from look-alike species using an unsupervised statistical model combined with orthogonal partial least-squares discriminant analysis. The results of this study provide an effective method for identifying and distinguishing P. chinensis (Bge.) Regel from similar plants.

A general procedure for establishing composite quality evaluation indices based on key quality attributes of traditional Chinese medicine.

Licorice, a medicinal herb and food flavor ingredient, has been widely used in traditional Chinese medicine (TCM) for the past 4000 years. In this study, we propose a new quality evaluation approach for licorice quality control based on the key quality attributes commonly used in TCM. The high quality of TCM formulations is ensured by verifying the genuine origin and implementing good agricultural and collection practices for each medicinal herb. In our study, the genuine production area, the harvest season, and the number of growth years were considered the key quality attributes of TCM. To ensure the representativeness of our analysis, we obtained a total of 158 licorice sample batches that differed in the number of growth years, the location of the production areas, and the season for harvesting. Initially, the 158 sample batches were subjected to ultra-high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry (UHPLC-QTOF-MS/MS). A preliminary screen identified 11 licorice compounds related to the three key quality attributes of TCM . An analysis by ultra-high-performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry (UHPLC-TQ-MS/MS) verified the presence of 34 compounds in all licorice samples. These 34 compounds included the 11 compounds related to the three key quality attributes of the samples, along with other bioactive components identified in previous studies. After using UHPLC-TQ-MS/MS to assess the signal peak intensities of the 34 compounds, we selected 17 licorice compounds to establish sample content evaluation indices, which were determined by high-performance liquid chromatography at four different wavelengths in all 158 licorice sample batches. Finally, the screen identified nine compounds that were closely associated with the quality attributes of licorice based on principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA). Our results suggested that liquiritin and eight other compounds could be used as quality control indicators of licorice, which provided a foundation to establish the TCM quality composite evaluation index (TCM QCEI). In summary, this research concept can serve as a reference for research on quality markers and the evaluation of TCM.

UHPLC-QQQ-MS/MS assay for the quantification of dianthrones as potential toxic markers of Polygonum multiflorum Thunb: applications for the standardization of traditional Chinese medicines (TCMs) with endogenous toxicity.

BACKGROUND: The raw and processed roots of Polygonum multiflorum Thunb (PM) are commonly used in clinical practice to treat diverse diseases; however, reports of hepatotoxicity induced by Polygoni Multiflori Radix (PMR) and Polygoni Multiflori Radix Praeparata (PMRP) have emerged worldwide. Thus, it is necessary for researchers to explore methods to improve quality standards to ensure their quality and treatment effects. METHODS: In the present study, an ultra-high performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-QQQ-MS/MS) method was optimized and validated for the determination of dianthrones in PMR and PMRP using bianthronyl as the internal standard. Chromatographic separation with a gradient mobile phase [A: acetonitrile and B: water containing 0.1% formic acid (v/v)] at a flow rate of 0.25 mL/min was achieved on an Agilent ZORBAX SB-C18 column (2.1 mm × 50 mm, 1.8 µm). The triple quadrupole mass spectrometer (TQMS) was operated in negative ionization mode with multiple reaction monitoring for the quantitative analysis of six dianthrones. Moreover, compounds 5 and 6 were further evaluated for their cytotoxicity in HepaRG cells by CCK-8 assay. RESULTS: The UHPLC-QQQ-MS/MS method was first developed to simultaneously determine six dianthrones in PMR and PMRP, namely, polygonumnolides C1-C4 (1-4), trans-emodin dianthrones (5), and cis-emodin dianthrones (6). The contents of 1-6 in 90 batches of PMR were in the ranges of 0.027-19.04, 0.022-13.86, 0.073-15.53, 0.034-23.35, 0.38-83.67 and 0.29-67.00 µg/g, respectively. The contents of 1-6 in 86 batches of commercial PMRP were in the ranges of 0.020-13.03, 0.051-8.94, 0.022-7.23, 0.030-12.75, 0.098-28.54 and 0.14-27.79 µg/g, respectively. Compounds 1-4 were almost completely eliminated after reasonable processing for 24 h and the contents of compounds 5 and 6 significantly decreased. Additionally, compounds 5 and 6 showed inhibitory activity in HepaRG cells with IC50 values of 10.98 and 15.45 µM, respectively. Furthermore, a systematic five-step strategy to standardize TCMs with endogenous toxicity was proposed for the first time, which involved the establishment of determination methods, the identification of potentially toxic markers, the standardization of processing methods, the development of limit standards and a risk-benefit assessment. CONCLUSION: The results of the cytotoxicity evaluation of the dianthrones indicated that trans-emodin dianthrones (5) and cis-emodin dianthrones (6) could be selected as toxic markers of PMRP. Taking PMR and PMRP as examples, we hope this study provides insight into the standardization and internationalization of endogenous toxic TCMs, with the main purpose of improving public health by scientifically using TCMs to treat diverse complex diseases in the future.

Advances in Understanding the Metabolites and Metabolomics of Polygonum multiflorum Thunb: A Mini-review.

BACKGROUND: The roots of Polygonum multiflorum (PM) are a well-known traditional Chinese medicine, widely used to treat a variety of conditions in Southeast Asia, South Korea, Japan and other countries. It is known that Polygoni Multiflori Radix Praeparata (PMRP) may enhance the efficacy and reduce the toxicity of PM. However, reports of adverse reactions, such as hepatotoxicity, caused by PM or PMRP, have continuously appeared around the world, which increased the known risks of the medication and gradually gained the extensive attention of many researchers. The chemical constituents of PM that cause hepatotoxicity have not been distinctly elucidated using the traditional phytochemical screening. Recently, with the rapid development of metabolomics, there has been a growing need to explore the potential hepatotoxic components and mechanisms of PM. METHODS: The metabolites and metabolomics of PM were searched by the Web of Science, PubMed, Google scholar and some Chinese literature databases. RESULTS: A brief description of metabolites and metabolomics of PM is followed by a discussion on the metabolite- induced toxicity in this review. More than 100 metabolites were tentatively identified and this will contribute to further understanding of the potential hepatotoxic components of PM. Meanwhile, some toxic compounds were identified and could be used as potential toxic markers of PM. CONCLUSION: This review mainly outlines the metabolites and metabolomics of PM that have been identified in recent years. This study could help to clarify the potential hepatotoxic components and metabolic mechanisms of PM and provide a scientific reference for its safe clinical use in the future.

In vivo hepatotoxicity screening of different extracts, components, and constituents of Polygoni Multiflori Thunb. in zebrafish (Danio rerio) larvae.

Polygonum multiflorum Thunb. (PM) is a traditional Chinese medicine, commonly used to treat a variety of diseases. However, the hepatotoxicity associated with PM hampers its clinical application and development. In this study, we refined the zebrafish hepatotoxicity model with regard to the following endpoints: liver size, liver gray value, and the area of yolk sac. The levels of alanine aminotransferase, aspartate transaminase, albumin, and microRNAs-122 were evaluated to verify the model. Subsequently, this model was used to screen different extracts, components, and constituents of PM, including 70 % EtOH extracts of PM, four fractions from macroporous resin (components A, B, C, and D), and 19 compounds from component D. We found that emodin, chrysophanol, emodin-8-O-ß-D-glucopyranoside, (cis)-emodin-emodin dianthrones, and (trans)-emodin-emodin dianthrones showed higher hepatotoxicity compared to other components in PM, whereas polyphenols showed lower hepatotoxicity. To the best of our knowledge, this study is the first to identify that dianthrones may account for the hepatotoxicity of PM. We believe that these findings will be helpful in regulating the hepatotoxicity of PM.

Multiflorumisides HK, stilbene glucosides isolated from Polygonum multiflorum and their in vitro PTP1B inhibitory activities.

A phytochemical study on a 70% EtOH extract of dried roots of Polygonum multiflorum resulted in the isolation of four undescribed stilbene glucosides, namely multiflorumisides HK (1-4). The structures of the natural products were elucidated by 1D and 2D nuclear magnetic resonance (NMR) as well as mass spectroscopy analyses. Among them, multiflorumiside J (3) and multiflorumiside K (4) belong to rare tetramer stilbene glucosides. Moreover, the in vitro inhibitory activities against protein tyrosine phosphatase 1B (PTP1B) were evaluated and the putative biosynthetic pathway was proposed. Notably, compounds 1-4 showed the inhibitory activity against PTP1B with the IC50 values of 1.2, 1.7, 1.5 and 4.6 µm, respectively. Based on the obtained results, stilbene glucosides could be the potential PTP1B inhibitors of P. multiflorum.

New phenolic constituents obtained from Polygonum multiflorum.

Objective: To isolate the phenolic compounds obtained from the dried roots of Polygonum multiflorum and investigate their pharmacological activities. Methods: The chemical constituents were isolated and purified by combining them with a macroporous resin (DM-8), MCI gel, and Sephadex LH-20 and by performing ODS column chromatography. Their structures were elucidated by 1D and 2D NMR analyses, as well as mass spectrometry. The isolated compounds were evaluated to determine their hepatoprotective and α-glucosidase inhibitory activities in vitro. Results: Two phenolic compounds, namely, polygonimitin E (1) and polygonimitin F (2), were isolated from the dried roots of P. multiflorum. Compound 2 (10 µmol/L) only showed moderate hepatoprotective activity against N-acetyl-p-aminophenol (APAP)-induced HepG2 cell damage. Unfortunately, these two compounds exhibited no α-glucosidase inhibitory activity. Conclusion: Compounds 1 and 2 were new compounds. Compound 2 could be one of the potential hepatoprotective constituents of P. multiflorum.

Identification of Calculus Bovis and its mixed varieties by ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF-MS) combined with the principal component analysis (PCA) method.

The method of ultra-high-performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-Q/TOF-MS) was established and combined with principal component analysis (PCA) to identify natural Calculus Bovis, in vitro cultured Calculus Bovis and artificial Calculus Bovis. PCA, which was particularly powerful in dealing with multicollinearity and variables that outnumber the samples, was used to analyze the UHPLC-MS data of the processed samples, and potential markers were analyzed and described based on orthogonal partial least-squares discriminant analysis. According to the results in this study, the approach of combining UHPLC-QTOF-MS with PCA was proven to be credible and could be used to identify Calculus Bovis from in vitro cultured Calculus Bovis and artificial Calculus Bovis and to determine if there is Calculus Bovis in patented Chinese medicines that should contained Calculus Bovis medicinal materials.

Characterization and identification of the chemical constituents of Polygonum multiflorum Thunb. by high-performance liquid chromatography coupled with ultraviolet detection and linear ion trap FT-ICR hybrid mass spectrometry.

Dianthrone derivatives are minor constituents of Polygonum multiflorum Thunb. (PM). These derivatives are potential hepatotoxic components in PM. Fraction D6 contains many dianthrone derivatives and was successfully enriched using an efficient three-step approach. An effective and reliable high-performance liquid chromatography (HPLC) technique coupled with ultraviolet detection (UV) and a linear ion trap FT-ICR hybrid mass spectrometry (HPLC-UV/LTQ-FT-ICR-MS) method were successfully developed to separate and identify the dianthrones of the fraction D6. The characteristic diagnostic fragment ions and characteristic fragmentation pathway of the seven dianthrone standards, namely, Polygonumnolide B1 (S1), Polygonumnolide C3 (S2), Polygonumnolide C2 (S3), Polygonumnolide E (S4), Polygonumnolide A1 (S5), Polygonumnolide A2 (S6) and cis-emodin dianthrones (S7), were compared with unknown compounds in fraction D6, and 45 dianthrone derivatives were characterized or tentatively identified. Of these derivatives, 32 new dianthrone derivatives were tentatively characterized in PM. Therefore, LTQ-FT-ICR-MS combined with a selective enrichment method provided a powerful means for analyzing dianthrone derivatives. This study provides a meaningful basis for correcting some mistakes in previous studies, as well as further quality control and pharmacological and toxicological research.

An optimized TaqMan real-time PCR method for authentication of ASINI CORII COLLA (donkey-hide gelatin).

In this study, probe/primers of high specificity and sensitivity were selected to analyze donkey-hide gelatin for donkey DNA and to look for horse, ox, and pig DNA as possible adulterants. The mitochondrial CO I genes in donkey, horse, and ox were selected as target sequences for design and synthesis of three pairs of specific probes and primers. In addition, eight pairs of probe/primers were obtained via literature search. Out of these eleven groups of probe/primers, those with the highest specificity and sensitivity were selected, which was fulfilled by the screening firstly with animal hide samples then the hide-glue samples. Other parameters that might affect detection specificity and efficiency-such as the amount of sampling and final concentration of primers-were also optimized. Replication tests were also conducted. The results showed that the selected probe/primers could accurately detect donkey DNA and horse, ox, and pig DNA in gelatin samples with good reproducibility. Analysis of four samples of on-market gelatin using this assay showed that two of the four samples indeed contained only donkey DNA, whereas the other two samples contained both donkey and horse DNA, indicating adulteration of these samples with horse hide. These results indicate that the TaqMan probe real-time PCR method can be used for identifying the purity of donkey DNA in gelatin samples, and can provide technical support for identifying adulterations in the gelatin market.

Identification of velvet antler and its mixed varieties by UPLC-QTOF-MS combined with principal component analysis.

Many species of velvet antler have been used as traditional medicine for thousands of years; however, as medicinal materials, velvet antler derived from different animals have different clinical effects. To distinguish the differences and homologies, ultra-performance liquid chromatography-quadruple-time of flight mass spectrometry (UPLC-QTOF-MS) coupled with principal component analysis (PCA) was developed and applied to identify these antler samples derived from Cervus nippon Temminck, Cervus elaphus Linnaeus and Rangifer tarandus Linnaeus, which were first tested and compared at the molecular level of protein. The UPLC-MS data of the trypsin digested samples were subjected to PCA, and the potential markers based on peptide were depicted to illustrate their differences. With the integrated strategy combining UPLC-QTOF-MS with PCA, the results from this study indicated that the proposed methods could be successfully applied to distinguish reindeer antler from sika deer antler and red deer antler, which were prescribed in the Chinese Pharmacopoeia (2015 edition).

[Market quality surveillance and analysis of chinese medicinal materials and decoction pieces in 2017].

With the rapid development of traditional Chinese medicine (TCM) in China as well as the implementation of the four most strict requirements, the quality of Chinese medicinal materials and decoction pieces had beem improved in recent years, however new problems and challenges were occurred. All the data of Chinese medicinal materials and decoction piece in special inspection,supervision test and evaluation inspection of drug administration department to were summarized and analyzed evaluate and analyze of the quality of Chinese medicinal materials and decoction pieces in 2017. On this basis, the relevant quality control strategies and suggestions were put forward for the relevant departments of China Food and Drug Administration to formulate and implement regulatory measures, furthermore to improve drug standards, and ensure the safety of medication.

[Identification of Fel Serpentis and its adulterants with specific PCR method].

The study aims at developing a convenient and specific method for the identification of Fel Serpentis DNA. The methods of Fel Serpentis genomic DNA purification were tested and optimized, four pairs of specific primers for the amplification of COⅠ, Cyt b and 16S were designed. Then the best pair of primers were selected according to the specificity and efficiency. The DNA fragment about 400 bp was amplified from 20 kinds of Fel Serpentis, whereas no DNA fragment was amplified from other animal samples under the same condition. This method is specific,accurate and reproducible, which provides a useful tool for the quality control of Fel Serpentis.

Acute toxicity screening of different extractions, components and constituents of Polygonum multiflorum Thunb. on zebrafish (Danio rerio) embryos in vivo.

Polygonum multiflorum Thunb. has been used widely in East Asia in treatment of diseases associated with aging. However, there are many reports referred to the toxicity of P. multiflorum, especially for liver adverse reactions. The toxicity of it is caused by over dosage or by the herb itself remains unclear. The aim of this study was to study the toxicity of different extractions, components and constituents of P. multiflorum, which were assessed in zebrafish embryos. Firstly, the difference of extracting solvent to the toxicity of P. multiflorum was researched to probe the influence of usages to the safety of P. multiflorum. The toxicity of 70% EtOH extract is considerably higher than that of other extracts. Secondly, 70% EtOH extract was subjected to macroporous resin (DM-8) eluting with a gradient of water and EtOH (H2O, 25% EtOH, 40% EtOH and 95% EtOH) to give four components (A-D). The toxicity of the component (D) showed higher than the other components (A-C). Thus, the component (D) was taken more attentions to research. Lastly, study on the chemical constituents of the component (D), 27 compounds, including 7 anthraquinones (1-7), 8 stilbenes (8-15), 7 anthrones (16-22), 3 cinnamic acid amides (23-25), 2 naphthols (26-27) were isolated and assessed in zebrafish embryos. Compounds 1-3, 16-22 and 26-27 showed severe toxicity against the zebrafish embryos while other compounds, such as stilbenes, showed no obvious toxicity.

[The analysis of multivariate image and chemometrics in TLC fingerprinting of artificial cow-bezoar].

A method of thin-layer fingerprinting chromatogram of artificial cow-bezoar was established with the developing solvent consisting of cyclohexane, ethyl acetate, acetic acid and methanol (2∶7∶1∶2), and 10% sulfuric acid ethanol solution sprayed as colour-developing agent. After heated at 105 ℃, TLC was recorded as an image in ultraviolet light at 366 nm which was converted into grayscale. By the gray value extracted from the grayscale, the multivariate data obtained from TLC of samples could be analyzed by chemometric method. The results indicated that samples from different manufacturers could be distinguished by this method and some specific bands were found out. All in one, this simple and practical method was suitable for the evaluation of quality difference.

Distinguishing the Chinese materia medica Tiepishihu from similar Dendrobium species of the same genus using histological and microscopic method.

The Chinese Materia Medica, Tiepishihu, used as a tonic for over one thousand years, is a well-known precious medicine in China. According to the Chinese Pharmacopoeia, its source is the species Dendrobium officinale Kimura et Migo, which is distinguished from other species in Dendrobium genus. However, these species from the same genus are similar with Tiepishihu and caused confusion in the market. To find a quick and simple method to distinguish Tiepishihu from other similar species, histologic and microscopic methods were combined together to investigate the transverse section of stem of Tiepishihu and other similar species. Phloroglucinol test solution with hydrochloric acid was used to reveal the lignified tissue by staining the transverse section of Tiepishihu and similar species. Results revealed the unique identification characteristics to distinguish Tiepishihu from similar species, which were difficult to distinguish by other methods. The identification characteristics of Tiepishihu include the cells of vascular bundle sheath were stained red, parenchyma cells were not stained red. What's more, other species can be distinguished from each other with microscopic and histological characteristics. These characteristics proved stable and can be easily observed by normal light microscopic examination. This method is rapid, accurate, stable, and inexpensive.

Identification of four cornua by ultra-performance liquid chromatography with time-of-flight mass spectrometry coupled with principal component analysis.

An ultra-high performance liquid chromatography with quadrupole time-of-flight mass spectrometry method coupled with principal component analysis was developed and applied to the identification of Cornu Antelopis, Cornu Bubali, Cornu Naemorhedi, and Cornu Bovis. The data obtained from the trypsin-digested samples were subjected to principal component analysis to classify these four cornua. Additionally, marker peptides of the cornua were determined by orthogonal partial least-squares discriminant analysis, and fragmentation tandem mass spectra of these marker peptides were evaluated. The results from this study indicate that the proposed method is reliable, and it has been successfully applied to the identification of variants of cornua commonly used in traditional Chinese medicine.