Identification of metabolites of geniposide in rat urine using ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

To elucidate the bioactive components of Lamiophlomis herba in the treatment of liver fibrosis via plasma pharmacochemistry and network pharmacology

Lamiophlomis Herba (LH) is a traditional Chinese and Tibetan dual-use herb with hemostatic and analgesic effects, and is widely used in the clinical treatment of traumatic bleeding and pain. In recent years, LH has been proven to treat liver fibrosis (LF), but the chemical components related to the pharmacological properties of LH in the treatment of LF are still unclear. Based on the theory of plasma pharmachemistry, the characteristic components in water extract and drug-containing plasma samples of LH were qualitatively analyzed by UPLC-Q-TOF-MS. The chemical components in plasma were screened and the targets were predicted by network pharmacology. Then, the predicted components and targets were verified in vitro by Elisa and qRT-PCR technology. Finally, the pharmacological effects of LH and its monomeric components were determined by hematoxylin-eosin staining of rat liver. A total of 50 chemical constituents were identified in LH, of which 12 were blood prototypes and 9 were metabolites. In vitro experiments showed that LH and its monomeric components luteolin, shanzhiside methyl ester, loganic acid, loganin, 8-O-acetyl shanzhiside methyl ester could increase the expression of antioxidant genes (NQO-1, HO-1) and decrease the expression of inflammatory genes (IL-6, IL-18), thereby reducing the expression of extracellular matrix-related genes and proteins (COL1A1, COL3A1, LN, α-sma, PC-III, Col-IV). In vivo experiments showed that LH could reduce the area of LF in rats in a dose-dependent manner, and shanzhiside methyl ester and 8-O-acetyl shanzhiside methyl ester may be the main components in pharmacodynamics. These effects may be mediated by LH-mediated Nrf2/NF-κB pathway. This study explored the potential pharmacodynamic components of LH in the treatment of LF, and confirmed that shanzhiside methyl ester and 8-O-acetyl shanzhiside methyl ester play a key role in the treatment of LF with LH.

Interpreting the efficacy enhancement mechanism of Chinese medicine processing from a biopharmaceutic perspective

Chinese medicine processing (CMP) is a unique pharmaceutical technology that distinguishes it from natural medicines. Current research primarily focuses on changes in chemical components to understand the mechanisms behind efficacy enhancement in processing. However, this paper presents a novel perspective on the biopharmaceutics of CMP. It provides a comprehensive overview of the current research, emphasizing two crucial aspects: the role of 'heat' during processing and the utilization of processing adjuvants. The paper highlights the generation of easily absorbed components through the hydrolysis of glycosides by 'heat', as well as the facilitation of dissolution, absorption, and targeted distribution of active components through the utilization of processing adjuvants. From a biopharmaceutic perspective, this paper provides a lucid comprehension of the scientific foundation for augmenting the efficacy of CMP. Moreover, it proposes a three-dimensional research framework encompassing chemical reactions, phase transitions, and biopharmaceutical properties to further investigate the mechanisms involved in enhancing the efficacy of CMP.

Comprehensive Metabolite Identification of Genipin in Rats Using Ultra-High-Performance Liquid Chromatography Coupled with High Resolution Mass Spectrometry

Genipin, an aglycone of geniposide, is a rich iridoid component in the fruit of Gardenia jasminoides Ellis and has numerous biological activities. However, its metabolic profiles in vivo and vitro remain unclear. In this study, an effective analytical strategy based on ultra-high-performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS) in positive and negative ion modes was developed to analyze and identify genipin metabolites in rat urine, blood, feces, and fecal fermentation in combination with many methods including post-collection data mining methods, high-resolution extracted ion chromatography (HREIC), and multiple mass defect filtering (MMDF). Simultaneously, the metabolites of genipin in vivo were verified by fecal fermentation of SD rats at different times. Finally, based on information such as reference substances, chromatographic retention behavior, and accurate mass determination, a total of 50 metabolites (including prototypes) were identified in vivo. Among them, 7, 31 and 28 metabolites in vivo were identified in blood, urine, and feces, respectively. Our results showed that genipin could generate different metabolites that underwent multiple metabolic reactions in vivo including methylation, hydroxylation, dehydroxylation, hydrogenation, sulfonation, glucuronidation, demethylation, and their superimposed reactions. Forty-six metabolites were verified in vitro. Meanwhile, 2 and 19 metabolites identified in blood and urine were also verified in fecal fermentation at different times. These results demonstrated that metabolites were produced in feces and reabsorbed into the body. In conclusion, the newly discovered metabolites of genipin can provide a new perspective for understanding its pharmacological effects and build the foundation for thee toxicity and safety evaluations of genipin.

A Comprehensive Strategy Based on UPLC-Q/TOF-MS for the Identification of Compounds in a Chinese Patent Medicine, Xiao'er Chiqiao Qingre Granules

The aim of this study was to establish a comprehensive strategy based on liquid chromatography coupled with mass spectrometry to potently identify as many compounds of Chinese patent medicine as possible. Ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS) was used to qualitatively analyze the Chinese patent medicine Xiao'er Chiqiao Qingre Granules (XCQG), which is recorded in the Chinese Pharmacopoeia. A novel strategy, including targeted, semi-targeted and non-targeted identification, was built to explore the compounds based on accurate mass, characteristic fragments, retention time of standard substances, databases or literature. Based on the integrated identification, 250 compounds were identified in total, including 7 alcohols, 3 aldehydes, 17 alkaloids, 9 amino acids, 10 coumarins, 30 flavonoids, 29 glycosides, 12 ketones, 7 lignans, 20 organic acids, 12 phenols, 11 phenylpropanoids, 9 quinones, 3 steroids, 26 terpenes, 14 volatile oils and 31 other compounds. A novel strategy for the identification of compounds in traditional Chinese medicine (TCM) was developed with Ultrahigh performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-Q/TOF-MS). It is also the first systematic study of compounds in XCQG, laying a foundation for further mechanism research of XCQG. More importantly, the strategy shows good application prospect in identifying compounds of TCM.

Updated Pharmacological Effects, Molecular Mechanisms, and Therapeutic Potential of Natural Product Geniposide

At present, the potential of natural products in new drug development has attracted more and more scientists’ attention, and natural products have become an important source for the treatment of various diseases or important lead compounds. Geniposide, as a novel iridoid glycoside compound, is an active natural product isolated from the herb Gardenia jasminoides Ellis (GJ) for the first time; it is also the main active component of GJ. Recent studies have found that geniposide has multiple pharmacological effects and biological activities, including hepatoprotective activity, an anti-osteoporosis effect, an antitumor effect, an anti-diabetic effect, ananti-myocardial dysfunction effect, a neuroprotective effect, and other protective effects. In this study, the latest research progress of the natural product geniposide is systematically described, and the pharmacological effects, pharmacokinetics, and toxicity of geniposide are also summarized and discussed comprehensively. We also emphasize the major pathways modulated by geniposide, offering new insights into the pharmacological effects of geniposide as a promising drug candidate for multiple disorders.

Detection and Identification of Catalpol Metabolites in the Rat Plasma, Urine and Faeces Using Ultra-high Performance Liquid Chromatography-Q Exactive Hybrid Quadrupole-orbitrap High-resolution Accurate Mass Spectrometry

BACKGROUND

Catalpol, an iridoid glycoside, is one of the richest bioactive components present in Rehmannia glutinosa. More and more metabolites of drugs have exhibited various pharmacological effects, thus providing guidance for clinical application. However, few researches have paid attention to the metabolism of catalpol.

OBJECTIVE

This study aimed to establish a rapid and effective method to identify catalpol metabolites and evaluate the biotransformation pathways of catalpol in rats.

METHODS

In this study, catalpol metabolites in rat urine, plasma and faeces were analyzed by UHPLC-Q-Exactive MS for the characterization of the metabolism of catalpol. Based on high-resolution extracted ion chromatograms (HREICs) and parallel reaction monitoring mode (PRM), metabolites of catalpol were identified by comparing the diagnostic product ions (DPIs), chromatographic retention times, neutral loss fragments (NLFs) and accurate mass measurement with those of catalpol reference standard.

RESULTS

A total of 29 catalpol metabolites were detected and identified in both negative and positive ion modes. Nine metabolic reactions, including deglycosylation, hydroxylation, dihydroxylation, hydrogenation, dehydrogenation, oxidation of methylene to ketone, glucuronidation, glycine conjugation and cysteine conjugation, were proposed.

CONCLUSION

A rapid and effective method based on UHPLC-Q-Exactive MS was developed to mine the metabolism information of catalpol. Results of metabolites and biotransformation pathways of catalpol suggested that when orally administrated, catalpol was firstly metabolized into catalpol aglycone, after which phase I and phase II reactions occurred. However, hydrophilic chromatography-mass spectrometry is still needed to further find the polar metabolites of catalpol.

Iridoids: Research Advances in Their Phytochemistry, Biological Activities, and Pharmacokinetics

Iridoids are a class of active compounds that widely exist in the plant kingdom. In recent years, with advances in phytochemical research, many compounds with novel structure and outstanding activity have been identified. Iridoid compounds have been confirmed to mainly exist as the prototype and aglycone and Ι and II metabolites, by biological transformation. These metabolites have been shown to have neuroprotective, hepatoprotective, anti-inflammatory, antitumor, hypoglycemic, and hypolipidemic activities. This review summarizes the new structures and activities of iridoids identified locally and globally, and explains their pharmacokinetics from the aspects of absorption, distribution, metabolism, and excretion according to the differences in their structures, thus providing a theoretical basis for further rational development and utilization of iridoids and their metabolites.

Differential Constituents in Roots, Stems and Leaves of Polygonum multiflorum Thunb. Screened by UPLC/ESI-Q-TOF-MS and Multivariate Statistical Analysis

The differential constituents in leaves, stems and roots of Polygonum multiflorum Thunb. were analyzed by ultra-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight mass spectrometry (UPLC/ESI-Q-TOF-MS) and by multivariate statistical analysis. The established extraction and analysis method showed relative standard deviations (RSDs) for intra-day precision of less than 3.40%, for repeatability of less than 4.06% and for stability of less than 5.10%. Principal component analysis and orthogonal projections to latent structures discriminant analysis of the UPLC/ESI-Q-TOF-MS data showed good ability to classify the leaves, stems and roots of P. multiflorum Thunb. The differential constituents, such as stilbenes, polygoacetophenoside, flavonoids and anthraquinones, accounting for variations between the leaves, stems and roots, were filtered through the variable importance in projection values and were further identified by elemental composition analysis, mass fragmentation data and retention times of available standards. Differences between the chemical compositions in the leaves, stems and roots of P. multiflorum Thunb. were closely related to their various therapeutic effects. This UPLC/ESI-Q-TOF-MS-based analytical strategy could be further utilized to evaluate the overall quality of traditional Chinese medicines and their differences of chemical constituents in different parts of the plant and/or in the plants of different geographical locations.

Metabolic profiles and pharmacokinetics of goitrin in rats through liquid chromatography combined with electrospray ionization-tandem mass spectrometry

Several chemical and biological studies have revealed R,S-goitrin as the main bioactive constituent of Isatis indigotica Fort., responsible for antiviral antiendotoxin activity; however, few pharmacokinetic studies have been conducted. To comprehend the kinetics of R,S-goitrin and promote its curative application, a rapid and sensitive UHPLC-MS/MS method was developed. The selected reaction monitoring transitions were m/z 130.0 → 70.0 for R,S-goitrin and m/z 181.1 → 124.0 for the internal standard in a positive-ion mode. The established UHPLC-MS/MS method achieved good linearity for R,S-goitrin at 10-2000 ng/mL. The intra- and interday accuracy levels were within ±9.7%, whereas the intraday and interday precision levels were <11.3%. The extraction recovery, stability and matrix effect were within acceptable limits. The validated method was successfully applied for the pharmacokinetic analysis of R,S-goitrin in rats after oral administration. Moreover, a total of six metabolites were structurally identified through UHPLC-Q/TOF-MS. The proposed metabolic pathways of R,S-goitrin in rats involve demethylation, acetylation, glutathionylation and oxygenation.

Metabolic profile analysis of Zhi-zi-chi decoction in feces of normal and chronic unpredictable mild stress-induced depression rats based on UHPLC-ESI-Q-TOF-MS/MS and multiple analytical strategies

Zhi-zi-chi decoction (ZZCD) has been verified by clinical application that it has definite curative effects and low side effects on depression. Because it is administered orally, the metabolites of ZZCD in the intestinal tract may influence the curative effects significantly. In this study, UHPLC-ESI-Q-TOF-MS/MS was used in combination with untargeted metabolomics-driven strategy, series product ion filtering and diagnostic fragment ion strategy for acquiring the comprehensive metabolic profile of ZZCD in feces of normal and chronic unpredictable mild stress (CUMS)-induced depression rats after oral administration, while the rat depression model was evaluated by behavior tests and plasma biochemical indices. Finally, a total of 56 compounds, including 35 prototype compounds and 21 metabolites, were identified or tentatively characterized in fecal samples. Among these, ten compounds were sieved as potential chemical markers that would reflect the antidepressant effect of ZZCD, which may offer important information for quality assessment, pharmacokinetic study and clinical security. In conclusion, the metabolic profile of ZZCD in normal and CUMS-induced depression rats would be helpful for the further study of anti-depression material basis and mechanism.

A total of 56 compounds from ZZCD were identified in feces of normal and depression rats. Then ten compounds were sieved as potential chemical markers that would reflect the antidepressant effect of ZZCD.

The profiling and identification of chemical components, prototypes and metabolites of Run-zao-zhi-yang capsule in rat plasma, urine and bile by an UPLC-Q-TOF/MSE -based high-throughput strategy

Run-zao-zhi-yang (RZZY) capsule, a traditional Chinese medicine formula, is popularly used for the treatment of dermatitis and eczema. However, few studies have been carried out on RZZY and its metabolites. In this study, we developed a three-step strategy to rapidly characterize the chemical constituents and metabolites of RZZY using ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry. A total of 41 chemical components were characterized from RZZY. Among these, there are 11 flavonoids, six alkaloids, six stilbene glycosides, five anthraquinones and 13 other compounds. In addition, 18 prototypes and 35 metabolites were detected in rat plasma, urine and bile. This study offers an applicable approach for high-throughput profiling and identification of chemical components and metabolites derived from traditional Chinese medicine formula in vivo, and also provides essential data for exploring bioactive ingredients and action mechanisms of RZZY.

Comprehensive investigation of in-vivo ingredients and action mechanism of iridoid extract from Gardeniae Fructus by liquid chromatography combined with mass spectrometry, microdialysis sampling and network pharmacology

Gardeniae Fructus is a widely used Traditional Chinese Medicines in treating various diseases. However, the absorbed components and metabolites of its main bioactive iridoid ingredients from iridoid extract of the fruits of Gardeniae Fructus in rat plasma need further study. In this study, a systematic method based on ultra-performance liquid chromatography-quadrupole-time-of-flight/mass spectrometry (UPLC-Q-TOF/MS) technique was developed to speculate the absorbed components and metabolites of iridoid extract in rat plasma after oral administration. A total of 19 compounds, including 9 prototype components and 10 metabolites were identified in plasma. 5 metabolites containing 4 new metabolites (M1, M2, M7, M10) were tentatively determined in rat plasma. Besides, Microdialysis-intensity-fading mass spectrometry (MD-IF-MS) method was originally employed to reveal the binding affinities with α-glucosidase for in-vivo prototype components and their metabolites. Finally, the absorbed constituents and the corresponding target proteins were used to generate compound-target network to find the related diseases and action pathways by a network pharmacology method. The results provide useful information for further study of pharmacology and in vivo mechanism of action of iridoid extract from the fruits of Gardeniae Fructus.

Iridoids and Other Monoterpenes in the Alzheimer's Brain: Recent Development and Future Prospects

Iridoids are a class of monoterpenoid compounds constructed from 10-carbon skeleton of isoprene building units. These compounds in their aglycones and glycosylated forms exist in nature to contribute to mechanisms related to plant defenses and diverse plant-animal interactions. Recent studies have also shown that iridoids and other structurally related monoterpenes display a vast array of pharmacological effects that make them potential modulators of the Alzheimer’s disease (AD). This review critically evaluates the therapeutic potential of these natural products by assessing key in vitro and in vivo data published in the scientific literature. Mechanistic approach of scrutiny addressing their effects in the Alzheimer’s brain including the τ-protein phosphorylation signaling, amyloid beta (Aβ) formation, aggregation, toxicity and clearance along with various effects from antioxidant to antiinflammatory mechanisms are discussed. The drug likeness of these compounds and future prospects to consider in their development as potential leads are addressed.

Exploration of serum biomarkers for predicting the response to Inchinkoto (ICKT), a Japanese traditional herbal medicine

INTRODUCTION

In patients with obstructive jaundice, biliary drainage sometimes fails to result in improvement. A pharmaceutical-grade choleretic herbal medicine, Inchinkoto (ICKT), has been proposed to exert auxiliary effects on biliary drainage; however, its effects are variable among patients.

OBJECTIVES

The aim of this study is to explore serum biomarkers that are associated with pharmaceutical efficacy of ICKT.

METHODS

Obstructive jaundice patients who underwent external biliary decompression were enrolled (n = 37). ICKT was given orally 3 times a day at daily dose of 7.5 g. Serum and bile samples were collected before, 3 h after, and 24 h after ICKT administration. The concentrations of total bilirubin, direct bilirubin, and total bile acid in bile specimens were measured. Metabolites in serum samples were comprehensively profiled using LC-MS/MS and GC-MS/MS. Pharmacokinetic analysis of major ICKT components was also performed.

RESULTS

ICKT administration significantly decreased serum ALT and increased bile volume after 24 h. The serum concentrations of ICKT components were not well correlated with the efficacy of ICKT. However, the ratio of 2-hydroxyisobutyric acid to arachidonic acid and the ratio of glutaric acid to niacinamide, exhibited good performance as biomarkers for the efficacy of ICKT on bile flow and ALT, respectively. Additionally, comprehensive correlation analysis revealed that serum glucuronic acid was highly correlated with serum total bilirubin, suggesting that this metabolite may be deeply involved in the pathogenesis of jaundice.

CONCLUSIONS

The present study indicates that ICKT is efficacious and provides candidates for predicting ICKT efficacy. Further validation studies are warranted.

The Metabolic Profiling of Isorhamnetin-3-O-Neohesperidoside Produced by Human Intestinal Flora Employing UPLC-Q-TOF/MS

Isorhamnetin-3-O-neohesperidoside is the major active substance of Puhuang, a traditional herb medicine widely used in clinical practice to tackle many chronic diseases. However, little is known about the interactions between this ingredient and intestinal flora. In this study, ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry together with automated data analysis software (Metabolynx™) was used for analysis of the metabolic profile of isorhamnetin-3-O-neohesperidoside by the isolated human intestinal bacteria. The parent and three metabolites isorhamnetin-3-O-glucoside, isorhamnetin and quercetin were detected and identified based on the characteristics of their deprotonated molecules. These metabolites indicated that isorhamnetin-3-O-neohesperidoside was firstly deglycosylated to isorhamnetin-3-O-glucoside and subsequently to the aglycone isorhamnetin, and the latter was demethylated to quercetin. The majority of bacteria such as Escherichia sp. 23 were capable of converting isorhamnetin-3-O-neohesperidoside to considerable amounts of aglycone isorhamnetin and further to minor amounts of quercetin, while minor amounts of isorhamnetin-3-O-glucoside were detected in minority of bacterial samples such as Enterococcus sp. 30. The metabolic pathway and metabolites of isorhamnetin-3-O-neohesperidoside by the different human intestinal bacteria were firstly investigated. Furthermore, the metabolites of isorhamnetin-3-O-neohesperidoside might influence the effects of traditional herb medicines. Thus, our study is helpful to further unravel how isorhamnetin-3-O-neohesperidoside and Puhuang work in vivo.

Characterization of picroside II metabolites in rats by ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Picroside II, a bioactive compound isolated from Picrorhiza scrophulariiflora Pennell, has been reported to have hepatoprotective, neuroprotective, and antioxidant effects. However, the detailed in vivo biotransformation of this compound has been rarely reported. This study aimed to investigate the metabolic profiles of picroside II in rats by using ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry. Metabolite structures were elucidated based on accurate mass measurements of deprotonated molecules and their fragmentation patterns. Thirteen metabolites were structurally identified, and the detailed metabolic pathways were proposed. The findings revealed that after oral administration, picroside II mainly undergoes four metabolic pathways. In the first pathway, picroside II is deglycosylated to generate aglycone, which is isomerized to a dialdehyde-type intermediate. A series of metabolic reactions, including glucuronidation, subsequently occurs. In the second pathway, picroside II is subjected to ester bond hydrolysis to form vanillic acid, which is further subjected to sulfate conjugation, glycine conjugation, glucuronidation, and demethylation. In the third pathway, picroside II is directly conjugated with glucuronic acid to yield a predominant metabolite (M01) in plasma. In the fourth pathway, picroside II is directly conjugated with sulfate. These findings provide insights into the in vivo disposition of picroside II and are useful to understand the mechanism of effectiveness and toxicity of this compound as well as P. scrophulariiflora-related preparations.

Comprehensive characterization of the in vitro and in vivo metabolites of geniposide in rats using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer

1. Geniposide (genipin 1-O-glucose), one of the major bioactive constituents isolated from Fructus Gardeniae, possesses many biological activities. In this study, an efficient strategy was developed using ultra-high-performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometer (UPLC-LTQ-Orbitrap) to profile the in vitro and in vivo metabolic patterns of geniposide in rat liver microsomes (RLMs), plasma, urine, and various tissues. And post-acquisition data-mining methods including extracted ion chromatogram (EIC), multiple mass defect filters (MMDF), fragment ion searching (FISh), and isotope pattern filtering (IPF) were adopted to characterize the known and unknown metabolites. 2. A total of 33 metabolites were detected and interpreted according to accurate mass measurement, diagnostic fragment ions, relevant drug biotransformation knowledge, and bibliography data. Among them, 17 metabolites were detected in the plasma, 31 metabolites were identified in the urine, six metabolites could be found in rat heart, 12 in liver, three in spleen, six in lung, 12 in kidney, six in brain, and four in RLMs. 3. A series of corresponding reactions such as hydrolysis, hydroxylation, taurine conjugation, hydrogenation, decarboxylation, demethylation, sulfate conjugation, cysteine S-conjugation, glucosylation, and their composite reactions were all discovered. 4. The results could provide comprehensive insights and guidance for elucidation of side effect mechanism and safety monitoring as well as for rational formulation design in drug delivery system. The newly discovered geniposide metabolites could be targets for future metabolism studies on the important chemical constituents from herbal medicines.

UPLC-MS/MS determination and gender-related pharmacokinetic study of five active ingredients in rat plasma after oral administration of Eucommia cortex extract

ETHNOPHARMACOLOGICAL RELEVANCE

Eucommiae cortex (EC), the bark of Eucommia ulmoides Oliv., has been traditionally used to treat many diseases in China for more than 2000 years. The pharmacological effects are primarily attributed to the presence of lignans, iridoids and phenolics, which are main active ingredients in EC.

AIM OF THE STUDY

First, to investigate the active ingredients that can be absorbed into the rat plasma according to which ingredients exhibit significant correlation of drug concentration-time curve. Second, to establish an efficient ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method for simultaneous determination of ingredients absorbed in rat plasma. Finally, to investigate gender effect on the pharmacokinetics of the ingredients absorbed in male and female rats plasma after oral administration with EC extract.

MATERIALS AND METHODS

18 ingredients from EC were detected by UPLC-MS/MS, 9 out of 18 ingredients were absorbed into rat plasma. And 5 ingredients exhibit significant correlation of drug concentration-time curve. They were pinoresinol di-O-β-d-glucopyranoside (PDG), geniposide (GE), geniposidic acid (GA), aucubin (AN) and chlorogenic acid (CA). The analytes were extracted from rat plasma via a simple protein precipitation procedure and osalmid was used as the internal standard. Chromatographic separation was achieved on a Waters ACQUITY HSS T3 column (2.1mm×100mm, 1.8μm) using a gradient elution program with acetonitrile and 0.1% formic acid water as the mobile phase, with a flow rate of 0.3mLmin(-1). The detection was performed on a triple-quadrupole tandem mass spectrometer by multiple reactions monitoring (MRM) mode in a positive ion mode via electrospray ionization (ESI). The transition monitored were /z 683.00[M+H](+)→235.10 for PDG, / z 389.00[M+H](+)→208.80 for GE, m/z 375.00[M+H](+)→194.79 for GA, m/z 364.00[M+NH4](+)→148.81 for AN, m/z 355.10[M+H](+)→162.84 for CA and m/z 230.03[M+H](+)→120.77 for internal standard.

RESULTS

The developed method showed good linearity over a wide concentration range, the lower limits of quantification and higher accuracy and precision for determination of the 5 analytes. Then the method was applied to study the pharmacokinetics in rats, and the results indicated that there were significant differences in pharmacokinetic parameters of the analytes between the male and female rats, and absorptions of these analytes in male group were all significantly higher than those in female group.

CONCLUSION

This study established an efficient, sensitive and selective UPLC-MS/MS method for simultaneous determination of the five ingredients in rat plasma, and it could be successfully applied to the comparative pharmacokinetic studies in male and female rats after oral administration with EC extract.

Determination of geniposide in adjuvant arthritis rat plasma by ultra-high performance liquid chromatography tandem mass spectrometry method and its application to oral bioavailability and plasma protein binding ability studies

A specific, sensitive and high throughput ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometric method (UHPLC-ESI-MS/MS) was established and validated to assay geniposide (GE), a promising anti-inflammatory drug, in adjuvant arthritis rat plasma: application to pharmacokinetic and oral bioavailability studies and plasma protein binding ability. Plasma samples were processed by de-proteinised with ice-cold methanol and separated on an ACQUITY UPLC™ HSS C18 column (100 mm × 2.1mm i.d., 1.8 μm particle size) at a gradient flow rate of 0.2 mL/min using acetonitrile-0.1% formic acid in water as mobile phase, and the total run time was 9 min. Mass detection was performed in selected reaction monitoring (SRM) mode with negative electro-spray ionization includes the addition of paeoniflorin (Pae) as an internal standard (IS). The mass transition ion-pair was followed as m/z 387.4 → 122.4 for GE and m/z 479.4 → 449.0 for IS. The calibration curves were linear over the concentration range of 2-50,000 ng/mL with lower limit of quantification of 2 ng/mL. The intra-day and inter-day precisions (RSD, %) of the assay were less than 8.4%, and the accuracy was within ± 6.4% in terms of relative error (RE). Extraction recovery, matrix effect and stability were satisfactory in adjuvant arthritis rat plasma. The UHPLC-ESI-MS/MS method was successfully applied to a pharmacokinetic study of GE after oral administration of depurated GE at 33, 66, 132 mg/kg and intravenous injection at 33, 66, 132 mg/kg in adjuvant arthritis (AA) rats. In addition, it was found that GE has rapid absorption and elimination, low absolute bioavailability, high plasma protein binding ability in AA rats after oral administration within the tested dosage range. It suggested that GE showed slow distribution into the intra- and extracellular space, and the binding rate was not proportionally dependent on plasma concentration of GE when the concentration of GE was below 5.0 μg/mL.

LC/MS/MS determination and pharmacokinetic studies of six compounds in rat plasma following oral administration of the single and combined extracts of Eucommia ulmoides and Dipsacus asperoides

AIM

To establish and apply a new LC/MS/MS method for the simultaneous, quantitative determination of six ingredients, aucubin (AU), geniposide (GP), geniposidic acid (GPA), pinoresinol diglucoside (PDG), secologanin (SLG), and loganin (LG) in single and combined extracts of Eucommia ulmoides and Dipsacus asperoides.

METHOD

Using the LC/MS/MS-ESI(-)-MRM mode to detect the six compounds, chromatographic separation was achieved on an Agilent Eclipse plus C18 column, and the mobile phase consisted of solvent A (CH3CN) and solvent B (H2O containing 0.01% CH3COOH V/V).

RESULTS

This method was successfully applied to quantify the six compounds in rat plasma after oral administration, and showed good precision, accuracy, reproducibility, and linear regression (r(2)>0.99).

CONCLUSION

The results showed that following the use of the two medicinal plants, for AU and GP, the values of Cmax markedly increased, and the values of cmax markedly decreased. It was found that the compatibility of the medicinal plants might affect their pharmacokinetic properties of their constituents.

Determination of metabolites of diosmetin-7-O-glucoside by a newly isolated Escherichia coli from human gut using UPLC-Q-TOF/MS

Different human intestinal bacteria were isolated and screened for their ability to transform diosmetin-7-O-glucoside. A Gram-negative anaerobic bacterium, strain 4, capable of metabolizing diosmetin-7-O-glucoside was newly isolated. Its 16S rRNA gene sequence displayed 99% similarity with that of Escherichia. Then strain 4 was identified as a species of the genus Escherichia and was named Escherichia sp. 4. Additionally, an ultraperformance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC-Q-TOF/MS) technique combined with Metabolynx software method was established to screen the metabolites of diosmetin-7-O-glucoside. Comparing the retention time and MS/MS spectrum, three metabolites were detected and tentatively identified. These metabolites were acquired by four proposed metabolic pathways including dehydroxylation, deglycosylation, methylation, and acetylation. Diosmetin-7-O-glucoside was mainly bioconverted to considerable amounts of diosmetin and minor amounts of acacetin by the majority of the isolated intestinal bacteria such as Escherichia sp. 4. Subsequently, several strains could degrade acacetin to produce methylated and acetylated acacetin. The metabolites and metabolic pathways of diosmetin-7-O-glucoside by human intestinal bacterium Escherichia sp. 4 were first investigated.

Characterization of metabolites of sweroside in rat urine using ultra-high-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry and NMR spectroscopy

Sweroside, a major active iridoid in Swertia pseudochinensis Hara, is recognized as an effective agent in the treatment of liver injury. Based on previous reports, the relatively short half-life (64 min) and poor bioavailability (approximately 0.31%) in rats suggested that not only sweroside itself but also its metabolites could be responsible for the observed hepato-protective effect. However, few studies have been carried out on the metabolism of sweroside. Therefore, the present study aimed at identifying the metabolites of sweroside in rat urine after a single oral dose (100 mg/kg). With ultra-high-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), the metabolic profile revealed 11 metabolites in rat urine, including phase I, phase II and aglycone-related products. The chemical structures of metabolites were proposed based on accurate mass measurements of protonated or deprotonated molecules and their fragmentation patterns. Our findings showed that the aglycone of sweroside (M05) and its glucuronide conjugate (M06) were principal circulating metabolites in rats. While several other metabolic transformations, occurring via reduction, N-heterocyclization and N-acetylation after deglycosylation, were also observed. Two metabolites (M05 and M06) were isolated from the rat urine for structural elucidation and identifcation of reaction sites. Both M05 and M06 were characterized by (1)H, (13)C and two-dimensional nuclear magnetic resonance (NMR) spectroscopy. UHPLC/Q-TOF-MS analysis has provided an important analytical platform to gather metabolic profile of sweroside.

Identification of the metabolites of gigantol in rat urine by ultra-performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight tandem mass spectrometry

Gigantol is a typical bibenzyl compound isolated from Dendrobii Caulis that has been widely used as a medicinal herb in China for the treatment of diabetic cataract, cancer and arteriosclerosis obliterans and as a tonic for stomach nourishment, saliva secretion promotion and fever reduction. However, few studies have been carried out on its in vivo metabolism. In the present study, a rapid and sensitive method based on ultra-performance liquid chromatography/electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UPLC-Q/TOF-MS) in positive ion mode was developed and applied to identify the metabolites of gigantol in rat urine after a single oral dose (100 mg/kg). Chromatographic separation was performed on an Acquity UPLC HSS T3 column (100 × 2.1 mm i. d., 1.8 µm) using acetonitrile and 0.1% aqueous formic acid as mobile phases. A total of 11 metabolites were detected and identified as all phase II metabolites. The structures of the metabolites were identified based on the characteristics of their MS, MS(2) data and chromatographic retention times. The results showed that glucuronidation is the principal metabolic pathway of gigantol in rats. The newly identified metabolites are useful to understand the mechanism of elimination of gigantol and, in turn, its effectiveness and toxicity. As far as we know, this is the first attempt to investigate the metabolic fate of gigantol in vivo.

Identification of the metabolites of myricitrin produced by human intestinal bacteria in vitro using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry

OBJECTIVE

To investigate the metabolic routes and metabolites of myricitrin, an important active ingredient of traditional herbal medicine, yielded by the isolated human intestinal bacteria, which have not been reported previously.

METHODS

Fresh human fecal samples were collected from a healthy female volunteer and about 100 different bacterial colonies were isolated. Ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry technique combined with Metabolynx™ software was used for analysis of the metabolic profile of myricitrin by the isolated human intestinal bacteria.

RESULTS

One hundred different bacterial colonies, which developed on plates, were picked up, and four of them were further identified by using the technique of 16S rRNA gene sequencing due to their relatively strong metabolic capacity toward myricitrin. Most of them belong to Escherichia. Parent compound and three metabolites (quercetin-3-O-rhamnoside, myricetin and quercetin) were detected in the isolated bacterial samples compared with blank samples. The metabolic pathways of myricitrin included deglycosylation and dehydroxylation.

CONCLUSIONS

These metabolites suggested that myricitrin was first dehydroxylated to quercetin-3-O-rhamnoside and subsequently deglycosylated to quercetin. Additionally, myricitrin could also be deglycosylated to the aglycon myricetin. Moreover, those metabolites might influence the biological effect of myricitrin in vivo, which led to affect the clinical effects of the medicinal plants and traditional herb medicines.

Analysis of the metabolites of isorhamnetin 3-O-glucoside produced by human intestinal flora in vitro by applying ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry

Isorhamnetin 3-O-glucoside, which is widely contained in many vegetables and rice, is expected to be metabolized by intestinal microbiota after digestion, which brings about the profile of its pharmacological effect. However, little is known about the interactions between this active ingredient and the intestinal flora. In this study, the preculture bacteria and GAM (general anaerobic medium) broth with isorhamnetin 3-O-glucoside were mixed for 48 h of incubation. Ultraperformance liquid chromatography/quadrupole time-of-flight mass spectrometry was used for analysis of the metabolites of isorhamnetin 3-O-glucoside in the corresponding supernatants of fermentation. The parent and five metabolites were found and preliminarily identified on the basis of the chromatograms and characteristics of their protonated ions. Four main metabolic pathways, including deglycosylation, demethoxylation, dehydroxylation, and acetylation, were summarized to explain how the metabolites were converted. Acetylated isorhamnetin 3-O-glucoside and kaempferol 3-O-glucoside were detected only in the sample of Escherichia sp. 12, and quercetin existed only in the sample of Escherichia sp. 4. However, the majority of bacteria could metabolize isorhamnetin 3-O-glucoside to its aglycon isorhamnetin, and then isorhamnetin was degraded to kaempferol. The metabolic pathway and the metabolites of isorhamnetin 3-O-glucoside yielded by different isolated human intestinal bacteria were investigated for the first time. The results probably provided useful information for further in vivo metabolism and active mechanism research on isorhamnetin 3-O-glucoside.

Combination of UHPLC/Q-TOF-MS, NMR spectroscopy, and ECD calculation for screening and identification of reactive metabolites of gentiopicroside in humans

The metabolic investigation of natural products is a great challenge because of unpredictable metabolic pathways, little knowledge on metabolic effects, and lack of recommended analytical methodology. Herein, a combined strategy based on ultrahigh-performance liquid chromatography coupled with electrospray ionization quadrupole time-of-flight tandem mass spectrometry (UHPLC/Q-TOF-MS), nuclear magnetic resonance (NMR) spectroscopy, and electronic circular dichroism (ECD) calculation was developed and employed for the human metabolism study of gentiopicroside (GPS), a naturally hepato-protective iridoid glycoside. The whole metabolic study consisted of three major procedures. First, an improved UHPLC/Q-TOF-MS method was used to separate and detect a total of 15 GPS metabolites that were obtained from urine samples (0 to 72 h) of 12 healthy male participants after a single 50-mg oral dose of GPS. Second, a developed "MS-NMR-MS" method was applied to accurately identify molecular structures of the observed metabolites. Finally, given that the associated stereochemistry may be a crucial factor of the metabolic activation, the absolute configuration of the reactive metabolites was revealed through chemical calculations. Based on the combined use, a pair of diastereoisomers (G05 and G06) were experimentally addressed as the bioreactive metabolites of GPS, and the stereochemical determination was completed. Whereas several novel metabolic transformations, occurring via oxidation, N-heterocyclization and glucuronidation after deglycosylation, were also observed. The results indicated that GPS has to undergo in vivo metabolism-based activation to generate reactive molecules capable of processing its hepato-protective activity.

A computational drug-target network for yuanhu zhitong prescription

Yuanhu Zhitong prescription (YZP) is a typical and relatively simple traditional Chinese medicine (TCM), widely used in the clinical treatment of headache, gastralgia, and dysmenorrhea. However, the underlying molecular mechanism of action of YZP is not clear. In this study, based on the previous chemical and metabolite analysis, a complex approach including the prediction of the structure of metabolite, high-throughput in silico screening, and network reconstruction and analysis was developed to obtain a computational drug-target network for YZP. This was followed by a functional and pathway analysis by ClueGO to determine some of the pharmacologic activities. Further, two new pharmacologic actions, antidepressant and antianxiety, of YZP were validated by animal experiments using zebrafish and mice models. The forced swimming test and the tail suspension test demonstrated that YZP at the doses of 4 mg/kg and 8 mg/kg had better antidepressive activity when compared with the control group. The anxiolytic activity experiment showed that YZP at the doses of 100 mg/L, 150 mg/L, and 200 mg/L had significant decrease in diving compared to controls. These results not only shed light on the better understanding of the molecular mechanisms of YZP for curing diseases, but also provide some evidence for exploring the classic TCM formulas for new clinical application.

Identification of the major metabolites of hyperoside produced by the human intestinal bacteria using the ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine (TCM), used in clinical practice for thousands of years, has been taken as a new way to tackle chronic diseases. In Chinese medicine, many ingredients which are known to have biological effects just pass through the gut, they do not get into the bloodstream. Study on interactions of these active ingredients with the intestinal bacteria is very helpful to unravel how TCM works.

AIM OF THE STUDY

Hyperoside is a major active constituent in many medicinal plants which are traditionally used in Chinese medicines for their neuroprotective, anti-inflammatory and anti-oxidative effects. It would be metabolized by intestinal bacteria after oral administration which leads to the variation of ethnopharmacological profile of these traditional medicines. Thus, it is necessary to investigate the metabolic routes and metabolites of hyperoside produced by human intestinal bacteria.

MATERIALS AND METHODS

Ultra performance liquid chromatography/quadrupole-time-of-flight mass spectrometry (UPLC/QTOF-MS) technique combined with Metabolynx(™) software was used for analysis of the metabolic profile of hyperoside by the isolated human intestinal bacteria from the human feces.

RESULTS

Parent compound and 6 metabolites (M1-M7) were detected in the isolated bacterial samples compared with blank samples. Quercetin, 3, 4-dihydroxyphenylacetic acid and 3, 4-dihydroxyphenylbenzoic acid (M2-M4) were only found in the sample of Bacteroides sp. 45. Dehydroxylation of hyperoside and the conjugates: acetylation and hydroxylation of hyperoside (M5-M7) were identified in the majority of isolated intestinal bacterial samples.

CONCLUSIONS

Only Bacteroides sp. 45 could metabolize hyperoside to form its aglycone quercetin, thereafter, quercetin was further metabolized to 3,4-dihydroxyphenylacetic acid and 3,4-dihydroxyphenylacetic acid. Furthermore, the majority of bacteria could metabolize hyperoside to dehydroxylation of hyperoside and the conjugates: hydroxylation and acetylation of hyperoside. In this study, the metabolic routes and metabolites of hyperoside produced by the different intestinal bacteria were investigated for the first time. Furthermore, the production of metabolites of hyperoside might influence the effects of traditional medicines. Thus, the study on the metabolism of hyperoside by human intestinal bacteria is of great importance to an understanding of the effects of traditional medicines.