Comprehensive Analysis of Bile Medicines Based on UHPLC-QTOF-MSE and Machine Learning

Based on UHPLC-QTOF-MSE analysis and quantized processing, combined with machine learning algorithms, data modeling was carried out to realize digital identification of bear bile powder (BBP), chicken bile powder (CIBP), duck bile powder (DBP), cow bile powder (CBP), sheep bile powder (SBP), pig bile powder (PBP), snake bile powder (SNBP), rabbit bile powder (RBP), and goose bile powder (GBP). First, 173 batches of bile samples were analyzed by UHPLC-QTOF-MSE to obtain the retention time-exact mass (RTEM) data pair to identify bile acid-like chemical components. Then, the data were modeled by combining support vector machine (SVM), random forest (RF), artificial neural network (ANN), gradient boosting (GB), AdaBoost (AB), and Naive Bayes (NB), and the models were evaluated by the parameters of accuracy (Acc), precision (P), and area under the curve (AUC). Finally, the bile medicines were digitally identified based on the optimal model. The results showed that the RF model constructed based on the identified 12 bile acid-like chemical constituents and random forest algorithm is optimal with ACC, P, and AUC > 0.950. In addition, the accuracy of external identification verification of 42 batches of bile medicines detected at different times is 100.0%. So based on UHPLC-QTOF-MSE analysis and combined with the RF algorithm, it can efficiently and accurately realize the digital identification of bile medicines, which can provide reference and assistance for the quality control of bile medicines. In addition, hyodeoxycholic acid, glycohyodeoxycholic acid, and taurochenodeoxycholic acid, and so forth are the most important bile acid constituents for the identification of nine bile medicines.

Quality Evaluation of Shexiang Tongxin Dropping Pill Based on HPLC Fingerprints Combined with HPLC-Q-TOF-MS/MS Method

Shexiang Tongxin Dropping Pill (STP) is a composite formula of traditional Chinese medicine that is widely used for the treatment of cardiovascular diseases. It consists of seven medicinal extracts thereof or materials, including Bufonis venenum, synthetic Moschus, Panax ginseng, Bovis calculus artifactus, Bear bile powder, Salvia miltiorrhiza Bge and synthetic borneol. However, it is considerably difficult to evaluate the quality of STP due to its complex chemical compositions. This paper was designed to explore a comprehensive and systematic method combining fingerprints and chemical identification for quality assessment of STP samples. Twenty batches of STP samples were analyzed by high-performance liquid chromatography (HPLC) and high-performance liquid chromatography-quadrupole time-of-flight tandem mass spectrometry. Ten common peaks were detected by HPLC fingerprint similarity evaluation system. Meanwhile, 100 compounds belonging to 4 structural characteristics, including 23 bufadienolides, 36 organic acids, 34 saponins and 7 other types, were systematically identified as the basic components in STP. This study could be used for clarifying the multiple bioactive substances and developing a comprehensive quality evaluation method of STP.

A Novel RP-UHPLC-MS/MS Approach for the Determination of Tryptophan Metabolites Derivatized with 2-Bromo-4'-Nitroacetophenone

Many biologically active metabolites of the essential amino acid L-tryptophan (Trp) are associated with different neurodegenerative diseases and neurological disorders. Precise and reliable methods for their determination are needed. Variability in their physicochemical properties makes the analytical process challenging. In this case, chemical modification of analyte derivatization could come into play. Here, we introduce a novel fast reversed-phase ultra-high-performance liquid chromatography (RP-UHPLC) coupled with tandem mass spectrometry (MS/MS) method for the determination of Trp and its ten metabolites in human plasma samples after derivatization with 2-bromo-4'-nitroacetophenone (BNAP). The derivatization procedure was optimized in terms of incubation time, temperature, concentration, and volume of the derivatization reagent. Method development comprises a choice of a suitable stationary phase, mobile phase composition, and gradient elution optimization. The developed method was validated according to the ICH guidelines. Results of all validation parameters were within the acceptance criteria of the guideline, i.e., intra- and inter-day precision (expressed as relative standard deviation; RSD) were in the range of 0.5-8.2% and 2.3-7.4%, accuracy was in the range of 93.3-109.7% and 94.7-110.1%, limits of detection (LODs) were in the range of 0.15-9.43 ng/mL, coefficients of determination (R2) were higher than 0.9906, and carryovers were, in all cases, less than 8.8%. The practicability of the method was evaluated using the blue applicability grade index (BAGI) with a score of 65. Finally, the developed method was used for the analysis of Alzheimer's disease and healthy control plasma to prove its applicability. Statistical analysis revealed significant changes in picolinic acid (PA), anthranilic acid (AA), 5 hydroxyindole-3-acetic acid (5-OH IAA), and quinolinic acid (QA) concentration levels. This could serve as the basis for future studies that will be conducted with a large cohort of patients.

Molecular Biomarkers in Cholangiocarcinoma: Focus on Bile

Hepatobiliary system cancers have demonstrated an increasing incidence rate in the past years. Without the presence of early symptoms, the majority of such cancers manifest with a set of similar symptoms, such as cholestasis resulting in posthepatic icterus. Differential diagnosis of hepatobiliary cancers is required for the therapy selection, however, the similarity of the symptoms complicates diagnostics. Thus, the search for molecular markers is of high interest for such patients. Cholangiocarcinoma (CCA) is characterized by a poor prognosis due to a low resectability rate, which occurs because this disease is frequently beyond the limits of surgical therapy at the time of diagnosis. The CCA is diagnosed by the combination of clinical/biochemical features, radiological methods, and non-specific serum tumor biomarkers, although invasive examination is still needed. The main disadvantage is limited specificity and sensitivity, which complicates early diagnostics. Therefore, prognostic and predictive biomarkers are still lacking and urgently needed for early diagnosis. In contrast to serum, bile is more accessible to identify biliary disease due to its simpler composition. Moreover, bile can contain higher concentrations of tumor biomarkers due to its direct contact with the tumor. It is known that the composition of the main bile component - bile acids, may vary during different diseases of the biliary tract. This review summarizes the recent developments in the current research on the diagnostic biomarkers for CCA in serum and bile and provides an overview of the methods of bile acids analysis.

tDCS Regulates ASBT-3-OxoLCA-PLOD2-PTEN Signaling Pathway to Confer Neuroprotection Following Rat Cerebral Ischemia-Reperfusion Injury

Humans exhibit a rich intestinal microbiome that contain high levels of bacteria capable of producing 3-oxo-lithocholic acid (3-oxoLCA) and other secondary bile acids (BAs). The molecular mechanism mediating the role of 3-oxoLCA in cerebral ischemia-reperfusion (I/R) injury remains unclear. We investigated the role of 3-oxoLCA in a rat cerebral I/R injury model. We found that the concentrations of 3-oxoLCA within the cerebrospinal fluid were increased following I/R. In the in vitro oxygen-glucose deprivation (OGD) model, the levels of intraneuronal 3-oxoLCA was elevated following OGD insult. We showed that the increase of membrane ASBT (apical sodium-dependent bile acid transporter) contributed to OGD-induced elevation of intraneuronal 3-oxoLCA. Increasing intraneuronal 3-oxoLCA promoted ischemia-induced neuronal death, whereas reducing 3-oxoLCA levels were neuroprotective. Our results revealed that PLOD2 (procollagen-lysine, 2-oxoglutarate 5-dioxygenases 2) functioned upstream of PTEN (the phosphatase and tensin homolog deleted on chromosome 10) and downstream of 3-oxoLCA to promote OGD-induced neuronal injury. We further demonstrated that direct-current stimulation (DCS) decreased the levels of intraneuronal 3-oxoLCA and membrane ASBT in OGD-insulted neurons, while bilateral transcranial DCS (tDCS) reduced brain infarct volume following I/R by inhibiting ASBT. Together, these data suggest that increased expression of ASBT promotes neuronal death via 3-oxoLCA-PLOD2-PTEN signaling pathway. Importantly, bilateral tDCS suppresses ischemia-induced increase of ASBT, thereby conferring neuroprotection after cerebral I/R injury.

Bile Acid Detection Techniques and Bile Acid-Related Diseases

Bile acid is a derivative of cholinergic acid (steroidal parent nucleus) that plays an important role in digestion, absorption, and metabolism. In recent years, bile acids have been identified as signaling molecules that regulate self-metabolism, lipid metabolism, energy balance, and glucose metabolism. The detection of fine changes in bile acids caused by metabolism, disease, or individual differences has become a research hotspot. At present, there are many related techniques, such as enzyme analysis, immunoassays, and chromatography, that are used for bile acid detection. These methods have been applied in clinical practice and laboratory research to varying degrees. However, mainstream detection technology is constantly updated and replaced with the passage of time, proffering new detection technologies. Previously, gas chromatography (GS) and gas chromatography-mass spectrometry (GC-MS) were the most commonly used for bile acid detection. In recent years, high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has developed rapidly and has gradually become the mainstream bile acid sample separation and detection technology. In this review, the basic principles, development and progress of technology, applicability, advantages, and disadvantages of various detection techniques are discussed and the changes in bile acids caused by related diseases are summarized.

Comprehensive evaluation integrating omics strategy and machine learning algorithms for consistency of calculus bovis from different sources

In the clinical application of Traditional Chinese Medicine (TCM) substitutes, the consistency evaluation of TCM substitutes from different sources is recognized as the main bottleneck. As the most widely used analytical method in TCM consistency evaluation, fingerprint similarity evaluation suffers from insufficient method sensitivity and poor conformity with the actual characteristics of TCM, which is difficult to adapt to the analytical needs of complex substance systems of TCM. This work aims to develop an effective and more accurate method for consistency evaluation using omics strategy and machine learning algorithms. The natural calculus bovis (NCB) were graded into three groups according to the similarity to in vitro cultured bovis (IVCB), and chemical markers between samples of each grade were screened out. Support vector machine (SVM) models with different kernels were then constructed by using the chemical markers as feature variables. The results showed that the classification accuracy of the SVM classifier of NCB and the consistency evaluation SVM model classifier was 95.74% and 100.0%, respectively. The approach demonstrated in the study presented a good analytical performance with higher sensitivity, accuracy for consistency evaluation of TCM.

The many facets of bile acids in the physiology and pathophysiology of the human liver

Bile acids perform vital functions in the human liver and are the essential component of bile. It is therefore not surprising that the biology of bile acids is extremely complex, regulated on different levels, and involves soluble and membrane receptors as well as transporters. Hereditary disorders of these proteins manifest in different pathophysiological processes that result in liver diseases of varying severity. In this review, we summarize our current knowledge of the physiology and pathophysiology of bile acids with an emphasis on recently established analytical approaches as well as the molecular mechanisms that underlie signaling and transport of bile acids. In this review, we will focus on ABC transporters of the canalicular membrane and their associated diseases. As the G protein-coupled receptor, TGR5, receives increasing attention, we have included aspects of this receptor and its interaction with bile acids.

Analysis of eight bile acids in urine of gastric cancer patients based on covalent organic framework enrichment coupled with liquid chromatography-tandem mass spectrometry

Gastric carcinoma is one of the most common and deadly forms of cancer. Early detection is critical for successful treatment of gastric cancer, and examination of BAs in urine may provide a critical diagnostic tool for identifying gastric cancer at stages when it can still be cured. Bile acids (BAs) are a crucial toxic factor correlated with the injury of gastric mucosa and as such, quantifying the amount of BA in patient's urine could provide a new means to quickly and non-invasively identify the presence of gastric cancer in the early stages. Here, a covalent organic framework (COF) material synthesized on the basis of 1,3,5-tris(4-nitrophenyl)benzene (TAPB) and pyromellitic dianhydride (PMDA) was used as stationary phase for SPE column that was coupled to LC-MS/MS for quantitative analysis of eight BAs in human urine, including cholic acid (CA), deoxycholic acid (DCA), glycochenodeoxycholic acid (GCDCA), glycocholic acid (GCA), taurochenodeoxycholic acid (TCDCA), lithocholic acid (LCA), hyodeoxycholic acid (HDCA), and chenodeoxycholic acid (CDCA). The enrichment effect of synthesized COF material was better than commercial SPE and HLB column. The sensitivity can increase 9.37- to 54.30- fold (calculated by the ratio of peak area between before and after enrichment). The probable mechanism is due to the great porosity and the similar polarity with BAs of the COF material. By compared with previous literatures, our method had the minimum limit of detection, which achieved 46.40, 25.75, 47.40, 47.37, 30.42, and 33.92 pg /mL, respectively, for GCA, GCDCA, CA, CDCA, HDCA and DCA after enrichment. These eight BAs also accomplished excellent linearity from 0.34 to 10,000 ng/mL. This material was successfully applied in the measurements of these six BAs in human urine from 76 gastric cancer patients and 32 healthy people. Compared to healthy people, levels of CA, CDCA, DCA, and HDCA were significantly elevated and levels of GCDCA were depressed, respectively, in gastric cancer patients. Our work suggests that these acids may act as potential biomarkers for gastric cancer and our framework provides a method for "non-invasive" diagnosis of gastric cancer.

A Powerful HPLC-ELSD Method for Simultaneous Determination of Fecal Bile Acids in T2DM Rats Interfered by Sanhuang Xiexin Tang

Bile acids (BAs) as important endogenous ligands can activate farnesoid X receptor (FXR) and G-protein-coupled bile acid receptor 1 (GPBAR1, also known as TGR5) signaling to regulate glycolipid metabolism. In this study, a simple, reliable and sensitive analysis method for simultaneous determination of four BAs from rat feces based on high-performance liquid chromatography with evaporative light scattering detector (HPLC-ELSD) was developed. Chromatographic analysis was performed with the mobile phases of acetonitrile and 0.2% formic acid. All the standard curves exhibited good linearity (R2 ≥ 0.99). The relative standard deviations of precision, stability and repeatability varied from 1.27 to 3.96%, 2.20 to 3.89% and 3.00 to 4.31%, respectively. The validated method was successfully applied to investigate the variation of four BAs in feces from T2DM rats after oral administration of Sanhuang Xiexin Tang (SXT). Data showed that SXT could remarkably increase the contents of conjunct BAs and decrease the contents of free BAs, which might contribute to ameliorate the symptoms of T2DM rats.

Liquid-Chromatographic Methods for Carboxylic Acids in Biological Samples

Carboxyl-bearing low-molecular-weight compounds such as keto acids, fatty acids, and other organic acids are involved in a myriad of metabolic pathways owing to their high polarity and solubility in biological fluids. Various disease areas such as cancer, myeloid leukemia, heart disease, liver disease, and lifestyle diseases (obesity and diabetes) were found to be related to certain metabolic pathways and changes in the concentrations of the compounds involved in those pathways. Therefore, the quantification of such compounds provides useful information pertaining to diagnosis, pathological conditions, and disease mechanisms, spurring the development of numerous analytical methods for this purpose. This review article addresses analytical methods for the quantification of carboxylic acids, which were classified into fatty acids, tricarboxylic acid cycle and glycolysis-related compounds, amino acid metabolites, perfluorinated carboxylic acids, α-keto acids and their metabolites, thiazole-containing carboxylic acids, and miscellaneous, in biological samples from 2000 to date. Methods involving liquid chromatography coupled with ultraviolet, fluorescence, mass spectrometry, and electrochemical detection were summarized.

Calculus bovis: A review of the traditional usages, origin, chemistry, pharmacological activities and toxicology

ETHNOPHARMACOLOGICAL RELEVANCE

Calculus bovis (C. bovis), a widespread known traditional animal drug in China and Japan, has been widely used for a long time to treat various diseases, including high fever, convulsion and stroke. The aim of the present paper is to comprehensively review knowledge about C. bovis in terms of traditional usages, origin, chemical constituents, pharmacological activities and toxicology to seek an applicable substitute for NCB and provide potential new strategies utilizing C. bovis. Additionally, directions and perspectives for future investigations regarding C. bovis are also discussed.

MATERIALS AND METHODS

In this paper, the traditional usages, origin, chemical constituents, pharmacology, and toxicology of C. bovis are comprehensively and systematically summarized by searching scientific databases, including Web of Science, PubMed, ScienceDirect, Springer, CNKI, Baidu Scholar and others. Additionally, some classic books of Chinese herbal medicine, academic papers authored by individuals with MSc and PhD degrees, local government reports as well as the state of local drug standards are also retrieved.

RESULTS

Currently, C. bovis mainly derives from four sources: natural Calculus bovis (NCB), Calculus bovis sativus (CBS), Cultured calculus bovis (CCB) and Calculus bovis artifactus (CBA). Owing to their different formation processes, the chemical constituents of the four kinds of C. bovis show certain differences. Additionally, over 44 chemical constituents have been isolated and identified from C. bovis, mainly including bile pigments, bile acids, cholesterols and amino acids. Further investigations have revealed a wide range of pharmacological effects of C. bovis, with effects on the nervous system, cardiovascular system, respiratory system, digestive system, immune system and others. Furthermore, NCB and CBA show hypotoxicity, but high concentrations of bilirubin can cause neurotoxicity and hearing impairment. Additionally, pharmacokinetic data for C. bovis are still lacking.

CONCLUSION

CBS contains analogous types and amounts of constituents and exerts similar therapeutic effects to NCB. Thus, CBS might be used as a sustainable substitute for NCB. Furthermore, the configuration and concentration of bile acids and bilirubin in C. bovis are responsible for the difference in pharmacological effects in the four types C. bovis. Further studies should focus on the structure-function relationship of bile acids and bilirubin in C. bovis by employing pharmacokinetics.

A review of analytical platforms for accurate bile acid measurement

Bile acids are acidic steroids which help in lipid absorption, act as signaling molecules, and are key intermediate molecules between host and gut microbial metabolism. Perturbations in the circulating bile acid pool can lead to dysregulated metabolic and immunological function which may be associated with liver and intestinal disease. Bile acids have chemically diverse structures and are present in a broad range of concentrations in a wide variety of samples with complex biological matrices. Advanced analytical methods are therefore required to identify and accurately quantify individual bile acids. Though enzymatic determination of total bile acid is most popular in clinical laboratories, these methods provide limited information about individual bile acids. Advanced analytical methods such as gas chromatography- and liquid chromatography-mass spectrometry and nuclear magnetic resonance spectroscopy are highly informative techniques which help in identification and quantification of individual bile acids in complex biological matrices. Here, we review the detection technologies currently used for bile acid identification and quantification. We further discuss the advantages and disadvantages of these analytical techniques with respect to sensitivity, specificity, robustness, and ease of use. Graphical abstract.

Detection technologies and metabolic profiling of bile acids: a comprehensive review

Bile acids (BAs) are important regulatory factors of life activities, which are involved in the regulation of glucose, lipid and energy metabolisms, and closely associated with intestinal hormones, microbiotas and energy balance. BAs abnormalities easily lead to inflammation and metabolic diseases, in turn, the progress of diseases could influence characteristics of BAs. Therefore, accurate detection of BAs contents is of great significance to disease prevention, diagnosis and treatment. At present, the most widely used enzymatic method in clinical practice is applicable to the detection of total bile acid (TBA). In laboratory research, different types of BAs can be accurately separated and quantified by liquid chromatography-mass spectrometry (LC-MS). The metabolic profiling of BAs based on detection technologies can completely and accurately monitor their types and contents, playing a crucial role in disease prevention, diagnosis and treatment. We herein reviewed the main detection technologies of BAs and the application of metabolic profiling in related diseases in recent years.

Rapid extraction and determination of 25 bioactive constituents in Alpinia oxyphylla using microwave extraction with ultra high performance liquid chromatography with tandem mass spectrometry

A novel and rapid microwave extraction and ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for the simultaneous determination of 25 bioactive constituents (including two new constituents) in Fructus Alpinia oxyphylla. The optimized conditions of the microwave extraction was a microwave power of 300 W, extraction temperature of 80°C, solvent-to-solid ratio of 30 mL/g and extraction time of 8 min. Separation was achieved on a Waters ACQUITY UPLC(®) HSS C18 column (2.1 mm× 50 mm, 1.8 μm) using gradient elution with a mobile phase consisting of acetonitrile and 1 mM ammonium acetate at a flow rate of 0.2 mL/min. This is the first report of the simultaneous determination of 25 bioactive constituents in Fructus Alpinia oxyphylla by ultra high performance liquid chromatography with tandem mass spectrometry. The method was validated with good linearity, acceptable precision and accuracy. The validated method was successfully applied to determine the contents of 25 bioactive constituents in Fructus Alpinia oxyphylla from different sources and the analysis results were classified by hierarchical cluster analysis, which indicated the effect of different cultivation regions on the contents of constituents. This study provides powerful and practical guidance in the quality control of Alpinia oxyphylla and lays the foundation for further research of Alpinia oxyphylla.