Pharmacokinetics,tissue distribution,and excretion studies of l‐isocorypalmine using ultra high performance liquid chromatography with tandem mass spectrometry

l ‐Isocorypalmine is a newly identified metabolite of l ‐tetrahydropalmatine with a unique dual pharmacological profile as a partial dopamine receptor 1 agonist and dopamine receptor 2 antagonist properties for treating cocaine use disorder. The purpose of this study was to explore the pharmacokinetic profiles, tissue distribution, and excretion of l ‐isocorypalmine in Sprague–Dawley rats. A sensitive and reliable ultra high performance liquid chromatography with tandem mass spectrometry method was developed and validated for determination of l ‐isocorypalmine in biological samples. The biological samples were extracted by liquid–liquid extraction and separated on a Bonshell ASB C₁₈ column (2.1 × 100 mm, 2.7 μm, Agela) with gradient mobile phase at the flow rate of 0.2 mL/min. The detection was performed by positive electrospray ionization with multiple reaction monitoring mode. Satisfactory linearity, precision, accuracy, extraction recovery, and acceptable matrix effect were achieved. The quantitative method was successfully applied to the pharmacokinetics, tissue distribution, and excretion study of l ‐isocorypalmine. The results showed that l ‐isocorypalmine was rapidly distributed, and eliminated from rat plasma and manifested linear dynamics in a dose range of 7.5–15 mg/kg. In addition, the results would be helpful for further clinical reference of l ‐isocorypalmine as a potential candidate drug for the treatment of cocaine addiction.     

Simultaneous determination of l‐tetrahydropalmatine and its active metabolites in rat plasma by a sensitive ultra‐high‐performance liquid chromatography with tandem mass spectrometry method and its application in a pharmacokinetic study

A sensitive and reliable ultra‐high‐performance liquid chromatography with tandem mass spectrometry (UHPLC–MS/MS) method was developed and validated for simultaneous determination of l ‐tetrahydropalmatine (l ‐THP) and its active metabolites l ‐isocorypalmine (l ‐ICP) and L ‐corydalmine (l ‐CD) in rat plasma. The analytes were extracted by liquid–liquid extraction and separated on a Bonshell ASB C₁₈ column (2.1 × 100 mm; 2.7 μm; Agela) using acetonitrile–formic acid aqueous as mobile phase at a flow rate of 0.2 mL/min in gradient mode. The method was validated over the concentration range of 4.00–2500 ng/mL for l ‐THP, 0.400–250 ng/mL for l ‐ICP and 1.00–625 ng/mL for l ‐CD. Intra‐ and inter‐day accuracy and precision were within the acceptable limits of <15% at all concentrations. Correlation coefficients (r ) for the calibration curves were >0.99 for all analytes. The quantitative method was successfully applied for simultaneous determination of l ‐THP and its active metabolites in a pharmacokinetic study after oral administration with l ‐THP at a dose of 15 mg/kg to rats.     

Integrated strategy based on high‐resolution mass spectrometry coupled with multiple data mining techniques for the metabolic profiling of Xanthoceras sorbifolia Bunge husks in rat plasma,urine, and feces

An integrated strategy based on high‐resolution mass spectrometry coupled with multiple data mining techniques was developed to screen the metabolites in rat biological fluids after the oral administration of Xanthoceras sorbifolia Bunge husks. Mass defect filtering, product ion filtering, and neutral loss filtering were applied to detect metabolites from the complex matrix. As a result, 55 metabolites were tentatively identified, among which 45 barrigenol‐type triterpenoid metabolites were detected in the feces, and six flavonoids and four coumarins metabolites were in the urine. Moreover, eight prototype constituents in plasma, 36 in urine and 23 in feces were also discovered. Due to the poor bioavailability of barrigenol type triterpenoids, most of them were metabolized by intestinal flora. Phase I metabolic reactions such as deglycosylation, oxidation, demethylation, dehydrogenation, and internal hydrolysis were supposed to be their principal metabolic pathways. Coumarins were found in all the biosamples, whereas flavonoids were mainly in the urine. Unlike the saponins, they were mainly metabolized through phase II metabolic reactions like glucuronidation and sulfonation, which made them eliminated more easily by urine. This work suggested the metabolic profile of X. sorbifolia husks for the first time, which will be very valuable for its further development.     

Urinary metabolomics analysis reveals the effect of volatile oil from Angelica sinensis on LPS‐induced inflammation rats

Lipopolysaccharide (LPS)‐induced inflammation occurs commonly and volatile oil from Angelica sinensis (VOAS) can be used as an anti‐inflammatory agent. The molecular mechanisms that allow the anti‐inflammatory factors to be expressed are still unknown. In this paper, we applied gas chromatography–mass spectrometry (GC–MS) and high‐performance liquid chromatography–time‐of‐flight mass spectrometry (LC‐Q/TOF–MS) based on a metabolomics platform coupled with a network approach to analyze urine samples in three groups of rats: one with LPS‐induced inflammation (MI); one with intervention with VOAS; and normal controls (NC). Our study found definite metabolic footprints of inflammation and showed that all three groups of rats, MI, intervention with VOAS and NC have distinct metabolic profiles in urine. The concentrations of 48 metabolites differed significantly among the three groups. The metabolites in urine were screened by the GC–MS and LC‐Q/TOF–MS methods. The significantly changed metabolites (p < 0.05, variable importance in projection > 1.5) between MI, NC and VOAS were included in the metabolic networks. Finally, hub metabolites were screened, including glycine, arachidonic acid, l ‐glutamate, pyruvate and succinate, which have high values of degree (k). the Results suggest that disorders of glycine, arachidonic acid, l ‐glutamate, pyruvate and succinate metabolism might play an important part in the predisposition and development of LPS‐induced inflammation. By applying metabolomics with network methods, the mechanisms of diseases are clearly elucidated.     

Systematic characterization of the metabolites of echinacoside and acteoside from Cistanche tubulosa in rat plasma,bile, urine and feces based on UPLC‐ESI‐Q‐TOF‐MS

Echinacoside (ECH) and acteoside (ACT), as the most and major active components of Cistanche tubulosa, were reported to possess cardioactive, neuroprotective and hepatocyte protective effects, as well as antibacterial, antioxidative effects. Recently, more studies have focused on their pharmacological activities. However, their metabolic profiles in vivo have not been sufficiently investigated. This study proposes an approach for rapidly identifying the complicated and unpredictable metabolites of ECH and ACT in rat plasma, bile, urine and feces, and systematically and comprehensively revealing their major metabolic pathways, based on powerful ultra‐high performance liquid chromatography coupled with quadrupole time‐of‐flight tandem mass spectrometry. Plasma, bile, urine and feces were collected from rats after a single 200 mg/kg oral dose. A total of 49 metabolites were detected in rat biological samples. Through analyzing metabolites in bile samples, it was found that ECH and ACT were subjected to a marked hepatic first‐pass effect in liver. Copyright © 2016 John Wiley & Sons, Ltd.     

Characterization and identification of the metabolites of Menthae Haplocalycis Herba water extracts in rat plasma,urine, and feces by ultra‐high performance liquid chromatography with linear ion trap‐Orbitrap mass spectrometry

Menthae Haplocalycis Herba has been utilized for food and medicinal purposes in China for thousands of years. It has various efficacies, including dispelling wind and heat and relieving sore throat. M. Haplocalycis Herba has been also widely used in food, cosmetics, spices, and other fields. Exploring the constituents and detecting the metabolites of M. Haplocalycis are of great significance to clarify the effective substances. However, the in vivo metabolites of M. Haplocalycis Herba water extract are still unclear. Herein, a sensitive and specific method, ultra‐high performance liquid chromatography with linear ion trap‐Orbitrap mass spectrometry, established in this assay was used to study the metabolism of M. Haplocalycis Herba water extract in rat plasma, urine, and feces. We characterized and identified 9, 50, and 34 metabolites in plasma, urine, and feces, respectively. Seven metabolic pathways, including phase Ⅰ (isomerization, demethylation, hydroxylation, and dehydration) and phase Ⅱ (sulfation and glucuronidation) were mainly involved in the metabolism. It is the first systematic study on the metabolism of M. Haplocalycis Herba water extract in vivo, which enrich current understanding of the metabolic behavior of M. Haplocalycis Herba water extract and provide a metabolic rationale for further in‐depth in vivo biotransformation and pharmacokinetic analysis.     

Identification and structural characterization of in vivo metabolites of ketorolac using liquid chromatography electrospray ionization tandem mass spectrometry (LC/ESI‐MS/MS)

In vivo metabolites of ketorolac (KTC) have been identified and characterized by using liquid chromatography positive ion electrospray ionization high resolution tandem mass spectrometry (LC/ESI‐HR‐MS/MS) in combination with online hydrogen/deuterium exchange (HDX) experiments. To identify in vivo metabolites, blood urine and feces samples were collected after oral administration of KTC to Sprague–Dawley rats. The samples were prepared using an optimized sample preparation approach involving protein precipitation and freeze liquid separation followed by solid‐phase extraction and then subjected to LC/HR‐MS/MS analysis. A total of 12 metabolites have been identified in urine samples including hydroxy and glucuronide metabolites, which are also observed in plasma samples. In feces, only O‐sulfate metabolite and unchanged KTC are observed. The structures of metabolites were elucidated using LC‐MS/MS and MSⁿ experiments combined with accurate mass measurements. Online HDX experiments have been used to support the structural characterization of drug metabolites. The main phase I metabolites of KTC are hydroxylated and decarbonylated metabolites, which undergo subsequent phase II glucuronidation pathways. Copyright © 2012 John Wiley & Sons, Ltd.     

Metabolic effects of Hedyotis diffusa on rats bearing Walker 256 tumor revealed by NMR‐based metabolomics

Hedyotis diffusa, a traditional Chinese herbal medicine, is widely used for oncotherapy and shows a positive effect in the clinical treatment. But its mechanism of anticancer activities is complicated and unclear. This study was undertaken to assess the therapeutic effects and reveal detailed mechanisms of H. diffusa for oncotherapy. A Walker 256 tumor‐bearing rat model was established, and metabolomic profiles of plasma and urine were obtained from ¹H NMR technique. Multivariate statistical analysis methods were used to characterize the discriminating metabolites between control (C), Walker 256 tumor‐bearing rats model (M), and H. diffusa treatment (H) groups. Finally, 13 and 10 metabolomic biomarkers in urine and plasma samples were further identified as characteristic metabolites in M group, whereas H group showed a partial metabolic balance recovered, such as ornithine, N‐acetyl‐l ‐aspartate, l ‐aspartate, and creatinine in urine samples, and acetate, lactate, choline, l ‐glutamine, and 3‐hydroxybutyrate in plasma samples. On the basis of the methods above, we hypothesized H. diffusa treatment reduced the injury caused by Walker 256 tumor and maintained a metabolic balance. Our study demonstrated that this method provided new insights into metabolic alterations in tumor‐bearing biosystems and researching on the effects of H. diffusa on the endogenous metabolism in tumor‐bearing rats.     

Identification of circulatory and excretory metabolites of meisoindigo in rat plasma,urine and feces by high‐performance liquid chromatography coupled with positive electrospray ionization tandem mass spectrometry

Meisoindigo has been a routine therapeutic agent in the clinical treatment of chronic myelogenous leukemia in China since the 1980s. However, information relevant to in vivo metabolism of meisoindigo is absent so far. In this study, in vivo circulatory metabolites of meisoindigo in rat plasma, as well as excretory metabolites in rat urine and feces, were identified by liquid chromatography/tandem mass spectrometry (LC/MS/MS). Integration of multiple reaction monitoring with conventional metabolic profiling methodology was adopted to enable a more sensitive detection of in vivo metabolites. By comparing with the MS/MS spectra and retention times of the in vitro reduced metabolites, the major metabolites in rat plasma were proposed to form from 3,3′ double bond reduction, whereas the minor metabolites were formed from reduction followed by N‐demethylation, and reduction followed by phenyl mono‐oxidation. The major metabolites in the rat urine were proposed to form from reduction followed by phenyl mono‐oxidation, and its glucuronide conjugation and sulfate conjugation, whereas the minor metabolites were formed from 3,3′ double bond reduction, N‐demethylation, reduction followed by N‐demethylation, phenyl di‐oxidation, phenyl mono‐oxidation and its glucuronide conjugation and sulfate conjugation. The major metabolites in the rat feces were proposed to form from reduction followed by phenyl mono‐oxidation, whereas the minor metabolites were formed from reduction followed by N‐demethylation, and reduction followed by phenyl di‐oxidation. The phase I metabolic pathways showed a significant in vitro–in vivo correlation in rat. Copyright © 2010 John Wiley & Sons, Ltd.     

Determination of a novel nonfluorinated quinolone,nemonoxacin, in human feces and its glucuronide conjugate in human urine and feces by high‐performance liquid chromatography–triple quadrupole mass spectrometry

Three methods were developed and validated for determination of nemonoxacin in human feces and its major metabolite, nemonoxacin acyl‐β‐ d ‐glucuronide, in human urine and feces. Nemonoxacin was extracted by liquid–liquid extraction in feces homogenate samples and nemonoxacin acyl‐β‐ d ‐glucuronide by a solid‐phase extraction procedure for pretreatment of both urine and feces homogenate sample. Separation was performed on a C₁₈ reversed‐phase column under isocratic elution with the mobile phase consisting of acetonitrile and 0.1% formic acid. Both analytes were determined by liquid chromatography–tandem mass spectrometry with positive electrospray ionization in selected reaction monitoring mode and gatifloxacin as the internal standard. The lower limit of quantitation (LLOQ) of nemonoxacin in feces was 0.12 µg/g and the calibration curve was linear in the concentration range of 0.12–48.00 µg/g. The LLOQ of the metabolite was 0.0010 µg/mL and 0.03 µg/g in urine and feces matrices, while the linear range was 0.0010–0.2000 µg/mL and 0.03–3.00 µg/g, respectively. Validation included selectivity, accuracy, precision, linearity, recovery, matrix effect, carryover, dilution integrity and stability, indicating that the methods can quantify the corresponding analytes with excellent reliability. The validated methods were successfully applied to an absolute bioavailability clinical study of nemonoxacin malate capsule. Copyright © 2014 John Wiley & Sons, Ltd.     

Characterization of In Vivo Metabolites of a Potential Anti-obesity Compound,the 3-Methyl-1H-Purine-2,6-Dione Derivative C-11, Employing Ultra-High Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry

C-11 (2-((7-Ethyl-3-methyl-8-(4-(2-(methyl(pyridin-2-yl)-amino)-ethoxy)phenyl)-2,6-dioxo-2,3,6,7-tetrahydro-1H-purin-1-yl)methyl)benzonitrile-one hydrochloride), which is based on the structure of rosiglitazone, was first synthesized in our laboratory and shown to be a promising anti-obesity drug candidate in our previous pharmacological study. Considering the importance of metabolic fate in vivo in the further development of drug candidates during early drug discovery, it is essential to characterize the metabolism of C-11 in vivo. In this work, a method based on ultra-high performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF-MS) was successfully developed to investigate the in vivo metabolic profile of C-11 in rats. Rat urine, feces, and plasma samples were collected from male Sprague–Dawley rats after intravenous administration of C-11 in a single dose of 30 mg kg⁻¹ body weight. Besides the parent drug, a total of 25 metabolites (including 18 phase I and 7 phase II metabolites) were detected and tentatively identified by comparing their mass spectrometry profiles with those of C-11. This enabled the metabolic pathways of C-11 to be proposed for the first time. Our results revealed that N-depyridinylation, N-demethylation, hydroxylation, glucuronidation, and sulfate conjugation are the predominant metabolic pathways of C-11 in rats. The present study provides systematic information on the metabolism of C-11 in vivo, which should lead to a better understanding of its safety and mechanism of action.

     

Rapid structural characterization of in vivo and in vitro metabolites of tinoridine using UHPLC–QTOF–MS/MS and in silico toxicological screening of its metabolites

Tinoridine is a nonsteroidal anti‐inflammatory drug and also has potent radical scavenger and antiperoxidative activity. However, metabolism of tinoridine has not been thoroughly investigated. To identify in vivo metabolites, the drug was administered to Sprague–Dawley rats (n = 5) at a dose of 20 mg kg^?1, and blood, urine and feces were collected at different time points up to 24 h. In vitro metabolism was delved by incubating the drug with rat liver microsomes and human liver microsomes. The metabolites were enriched by optimized sample preparation involving protein precipitation using acetonitrile, followed by solid‐phase extraction. Data processes were carried out using multiple mass defects filters to eliminate false‐positive ions. A total of 11 metabolites have been identified in urine samples including hydroxyl, dealkylated, acetylated and glucuronide metabolites; among them, some were also observed in plasma and feces samples. Only two major metabolites were formed using liver microsomal incubations. These metabolites were also observed in vivo. All the 11 metabolites, which are hitherto unknown and novel, were characterized by using ultrahigh‐performance liquid chromatography–quadrupole time‐of‐flight tandem mass spectrometry in combination with accurate mass measurements. Finally, in silico toxicological screening of all metabolites was evaluated, and two metabolites were proposed to show a certain degree of lung or liver toxicity. Copyright © 2015 John Wiley & Sons, Ltd.     

Liquid chromatography/mass spectrometric analysis of rat samples for in vivo metabolism and pharmacokinetic studies of ginsenoside Rh2

In vivo metabolism and pharmacokinetic studies on rat were conducted for ginsenoside Rh2, one of the components from ginseng that shows promise of anticancer activity. Liquid chromatography/mass spectrometry (LC/MS) and tandem mass spectrometry (MS/MS) with electrospray ionization were used to determine Rh2 and its metabolites in rat plasma, urine and feces. An average half-life of 16 min in plasma was obtained after intravenous administration to male Sprague-Dawley rats at 5 mg/kg. No Rh2 was detected in plasma samples collected from 0 to 24 h following oral administration at 100 mg/kg, and only 0.12-0.25% of the dosed amount was found in the feces samples collected from 0 to 48 h after oral administration at 100 mg/kg. Three metabolites of Rh2 were detected in the feces samples. Oxygenation and deglycosylation were found to be the major metabolic pathways of Rh2. Intense metabolism, rather than excretion, appears to be the reason for the fast clearance of this ginsenoside.     

Metabolism of TM‐2, a potential antitumor drug,in rats by using LC–MS

TM‐2 (13‐(N‐Boc‐3‐i‐butylisoserinoyl‐4,10‐β‐diacetoxy‐2‐α‐benzoyloxy‐5‐β‐20‐epoxy‐1,13‐α‐dihydroxy‐9‐oxo‐19‐norcyclopropa[g]tax‐11‐ene) is a novel semisynthetic taxane derivative. Our previous study suggested that TM‐2 is a promising antitumor analogue. In this paper, the metabolism of TM‐2 was investigated in rats following intravenous administration. Two different types of mass spectrometry—hybrid linear trap quadrupole orbitrap (LTQ‐Orbitrap) mass spectrometry and triple‐quadrupole tandem (QQQ) mass spectrometry—were employed to acquire structural information of TM‐2 metabolites. A total of 17 components were identified as the metabolites of TM‐2 in bile, feces, and urine samples. Accurate mass measurement using LC–LTQ‐Orbitrap‐MS was used to determine the accurate mass data and elemental composition of metabolites thereby confirming the proposed structures of the metabolites. The metabolites proposed were mainly oxidates of TM‐2, including methoxy, hydroxyl, dihydroxy, and trihydroxyl analogues. The major metabolic pathway of TM‐2 was the hydroxylation of the taxane ring or the lateral chain. These important metabolic data serve as a useful resource to support further research of TM‐2.     

Metabolic profile of Kudiezi injection in rats by UHPLC coupled with Fourier transform ion cyclotron resonance mass spectrometry

In this study, a reliable and sensitive ultra‐high performance liquid chromatography coupled with fourier transform ion cyclotron resonance mass spectrometry method was developed for the systematic study of the metabolic profile of Kudiezi injection in rat plasma, bile, urine, and feces after intravenous administration of a single dose. The chromatographic separation was performed on an Agilent Eclipse Plus C₁₈ column (4.6 mm × 50 mm, 1.8 μm) and the identification of prototype components and metabolites was achieved on a Bruker Solarix 7.0 T ultra‐high resolution spectrometer in negative ion mode. Results indicated that a total of 76 constituents including 29 prototype compounds and 47 metabolites (10 phase I metabolites and 37 phase II metabolites) were tentatively identified. And the metabolic pathways of these prototype compounds including hydroxylation, dehydrogenation, glucuronidation, and sulfate conjugation. In conclusion, the developed method with high resolution and sensitivity was effective for screening and identification of prototypes and metabolites of Kudiezi injection in vivo. Moreover, these results would provide significant information for further pharmacokinetic and pharmacological research of Kudiezi injection in vivo.     

Identification of metabolites of isopropyl 3‐(3,4‐dihydroxyphenyl)‐2‐hydroxypropanoate in rats by high‐performance liquid chromatography combined with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry

Isopropyl 3‐(3,4‐dihydroxyphenyl)‐2‐hydroxypropanoate (IDHP) is an investigational new drug having the capacity for treating ailments in the cardiovascular and cerebrovascular system. In this work, a rapid and sensitive method using high‐performance liquid chromatography coupled with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry (HPLC‐ESI‐Q‐TOF‐MS) was developed to reveal the metabolic profile of IDHP in rats after oral administration. The method involved pretreatment of the samples by formic acid–methanol solution (v/v, 5:95), chromatographic separation by an Agilent Eclipse XDB‐C₁₈ column (150 × 4.6 mm i.dx., 5 μm) and online identification of the metabolites by Q‐TOF‐MS equipped with electrospray ionizer. A total of 16 metabolites from IDHP, including four phase I metabolites and 12 phase II metabolites, were detected and tentatively identified from rat plasma, urine and feces. Among these metabolites, Danshensu (DSS), a hydrolysis product of IDHP, could be further transformed to 11 metabolites. These results indicated that DSS was the main metabolite of IDHP in rats and the major metabolic pathways of IDHP in vivo were hydrolysis, O‐methylation, sulfation, glucuronidation and reduction. The results also demonstrated that renal route was the main pathway of IDHP clearance in rat. The present study provided valuable information for better understanding the efficacy and safety of IDHP. Copyright © 2015 John Wiley & Sons, Ltd.     

Metabolic profiling of quercetin in rats using ultra‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry

Quercetin, a kind of major flavonoid found in many traditional chinese medicines, is an effective substance for treatments such as lowering blood lipids. However, the studies on quercetin have been mainly focused on its pharmacological effect; the treatment of diseases on a material basis, particularly the metabolites derived from quercetin in vivo , has not been evaluated. In this study, we determined the levels, distributions and types of quercetin's metabolites in plasma, urine, feces and bile of rats after a single oral administration of quercetin at a dose of 80 mg/kg, using ultra‐performance liquid chromatography/quadrupole‐time‐of‐flight mass spectrometry (UPLC‐Q‐TOF/MS). A total of 36 metabolites of quercetin were identified, including 11 metabolites in plasma, 34 metabolites in urine, 12 metabolites in feces and 21 metabolites in bile. The results showed that phase I metabolites were reduction metabolites and phase II metabolites mainly included glucuronidation, sulfation and methylation metabolites. These results provide important information on the metabolism of quercetin, which will be helpful for its further development and utilization.     

Identification and quantitative analysis of physalin D and its metabolites in rat urine and feces by liquid chromatography with triple quadrupole time‐of‐flight mass spectrometry

Physalin D is known to show extensive bioactivities. However, no excretion study has elucidated the excretion of physalin D and its metabolites. This study investigates the excretion of physalin D and its metabolites in rats. Metabolites in rat urine and feces were separated and identified by liquid chromatography with triple quadrupole time‐of‐flight mass spectrometry. Furthermore, a validated high‐performance liquid chromatography with tandem mass spectrometry method was developed to quantify physalin D, physalin D glucuronide, and physalin D sulfate in rat feces and urine after the intragastric administration of physalin D. The analyte showed good linearity over a wide concentration range (r  > 0.995), and the lower limit of quantification was 0.0532 μg/mL and 0.226 μg/g for urine and feces, respectively. Nine metabolites, including five phase I and four phase II metabolites, were identified and clarified after dosing in vivo. Only 4.0% of the gavaged dose, including physalin D and its phase II metabolites, was excreted in urine, whereas 10.8% was found in feces in the unchanged form. The results indicate that the extensive and rapid metabolism may be the main factors leading to the short half‐life of physalin D. These results can provide a basis for further studies on the structural modification and pharmacology of physalin D.     

Characterization of ginsenoside compound K metabolites in rat urine and feces by ultra‐performance liquid chromatography with electrospray ionization quadrupole time‐of‐flight tandem mass spectrometry

Ginsenoside compound K (CK) is an active metabolite of ginsenoside and has been shown to have ameliorative property in various diseases. However, the detailed in vivo metabolism of this compound has rarely been reported. In the present study, a method using liquid chromatography quadrupole time‐of‐flight tandem mass spectrometry together with multiple data processing techniques, including extracted ion chromatogram, multiple mass defect filter and MS/MS scanning, was developed to detect and characterize the metabolites of CK in rat urine and feces. After oral administration of CK at a dose of 50 mg/kg, urine and feces were collected for a period of time and subjected to a series of pretreatment. A total of 12 metabolites were tentatively or conclusively identified, comprising 11 phase I metabolites and a phase II metabolite. Metabolic pathways of CK has been proposed, including oxidation, deglycosylation, deglycosylation with sequential oxidation and dehydrogenation and deglycosylation with sequential glucuronidation. Relative quantitative analyses suggested that deglycosylation was the main metabolic pathway. The result could offer insights for better understanding of the mechanism of its pharmacological activities.     

Structural Elucidation of in vivo and in vitro Metabolites of Epiberberine in Rat and Its Liver and Intestines by Liquid Chromatography-Tandem Mass Spectrometry

The in vivo and in vitro metabolism of epiberberine was investigated using a highly specific and sensitive liquid chromatography–mass spectrometry (LC–MS/MS) method. In vivo samples including rat urine, feces, and plasma samples were collected individually after ingestion of 35 mg/kg epiberberine to healthy rats. In vitro samples were prepared by incubating epiberberine with homogenized liver and intestinal flora of rats, respectively. As a result, at least 17, 3 and 5 metabolites were found in rat urine, feces, and plasma, respectively. Additionally, 1 and 3 metabolites were found in the rat intestinal flora and homogenized liver incubation mixtures, respectively.