Main Metabolic Reactions Research Articles

Detection and Characterization of the Metabolites of Ciwujianoside B in Rats Based on UPLC-Fusion Lumos Orbitrap Mass Spectrometry.

We previously conducted a systematic study on the metabolic process and products of hederasaponin B in rats. We hypothesized that the sugar chain structures play a key role in the metabolism of triterpenoid saponins. To verify this hypothesis, we conducted metabolic research on ciwujianoside B ascribed to the same sugar chains and a distinct aglycone and compared it with hederasaponin B. Specifically, we collected feces, urine, and plasma of rats after gavage with ciwujianoside B and identified 42 metabolites by UPLC-Fusion Lumos Orbitrap mass spectrometry. Finally, ciwujianoside B metabolism and hederasaponin B metabolism were compared, reaching the following conclusions: (i) more than 40 metabolites were identified in both, with the majority of metabolites identified in feces; (ii) the corresponding metabolic pathways in vivo were basically similar, including deglycosylation, acetylation, hydroxylation, glucuronidation, oxidation, and glycosylation; and (iii) deglycosylation was considered the main metabolic reaction, and its metabolites accounted for approximately 50% of all metabolites. Overall, this study provides a foundation for further research on the metabolism of triterpenoid saponins.

Existence forms of Tiantian Capsules and its raw material Aloe in rats

This study explored the existence forms(original constituents and metabolites) of Tiantian Capsules, Aloe, and Tiantian Capsules without Aloe in rats for the first time, aiming to clarify the contribution of Aloe to the existence form of Tiantian Capsules. Rats were administrated with corresponding drugs by gavage once a day for seven consecutive days. All urine and feces samples were collected during the seven days of administration, and blood samples were collected 0.5, 1, and 1.5 h after the last administration. UHPLC-Q-TOF-MS was employed to detect and identify the original constituents and metabolites in the samples. A total of 34, 28, and 2 original constituents and 64, 94, and 0 metabolites were identified in the samples of rats administrated with Aloe, Tiantian Capsules, and Tiantian Capsules without Aloe, respectively. The main metabolic reactions were methylation, hydrogenation, hydroxylation, dehydroxylation, glucuronidation, and sulfation. This study clarified for the first time the existence forms and partial metabolic pathways of Aloe, Tiantian Capsules, and Tiantian Capsules without Aloe in rats, laying a foundation for revealing their effective forms. The findings are of great significance to the research on the functioning mechanism and quality control of Aloe and Tiantian Capsules.

The Metabolism Study of Oleraisoquinoline in Rats Using Ultrahigh- performance Liquid Chromatography-electrospray Coupled with Quadrupole Time-of-flight Mass Spectrometry and its Bioactivities

Objective: This study aimed to investigate the main metabolites and metabolic pathways of oleraisoquinoline in rats, a new alkaloid isolated from Portulaca oleracea L., and test its antioxidation and anticholinesterase effects. Methods: Ultra-high-performance liquid chromatography-electrospray coupled with quadrupole time-of-flight mass spectrometry (UHPLC-ESI-Q-TOF/MS) was applied to study the metabolism of oleraisoquinoline. Furthermore, 1,1‑diphenyl‑2‑picrylhydrazyl assay and modified Ellman’s method were used to test the antioxidation and anticholinesterase effects of oleraisoquinoline, respectively. Results: The metabolism results of oleraisoquinoline showed, after its administration through the tail vein of rats, 4 metabolites in the plasma samples, 17 metabolites in the urine sample, and 2 metabolites in the feces sample. The main metabolic pathways were hydrolyzation, oxidation, hydroxylation, sulfonation, glucuronidation, acetylation, and methylation. Additionally, IC50 values of antioxidant and anticholinesterase activities were 13.819 ± 0.005 μM and 10.551 ± 0.069 μM, respectively. Conclusion: 21 metabolites were found in the rat’s plasma, urine, and feces samples, and the metabolic pathways included hydrolyzation, oxidation, hydroxylation, sulfonation, glucuronidation, acetylation, and methylation; among them, sulfonation was the main metabolic reaction. Meanwhile, oleraisoquinoline also showed extremely good antioxidant and anticholinesterase activities.

Comprehensive Study of In vivo and In vitro Metabolites of Cycloastragenol Based on UHPLC-Q-Exactive Orbitrap Mass Spectrometer.

Cycloastragenol (CAG) is a sapogenin derived from the main bioactive constituents of Astragali Radix (AR). However, the current research on CAG metabolism in vivo and in vitro is still inadequate, and the metabolite cluster is incomplete due to incomplete analysis strategy. The objective of this study was to screen and identify the metabolic behavior of CAG in vivo and in vitro. A simple and rapid analysis strategy based on UHPLC-Q-Exactive Orbitrap mass spectrometry combined with data-mining processing technology was developed and used to screen and identify CAG metabolites in rat body fluids and tissues after oral administration. As a result, a total of 82 metabolites were fully or partially characterized based on their accurate mass, characteristic fragment ions, retention times, corresponding Clog P values, and so on. Among the metabolites, 61 were not been reported in previous reports. These metabolites (6 metabolites in vitro and 91 in vivo) were generated through reactions of hydroxylation, glucuronidation, sulfation, hydrogenation, hydroxylation, demethylation, deisopropylation, dehydroxylation, ring cleavage, and carboxyl substitution and their composite reactions, and the hydroxylation might be the main metabolic reaction of CAG. In addition, the characteristic fragmentation pathways of CAG were summarized for the subsequent metabolite identification. The current study not only clarifies the metabolite cluster-based and metabolic regularity of CAG in vivo and in vitro, but also provides ideas for metabolism of other saponin compounds.

The dynamic metabolic profile of Qi-Yu-San-Long decoction in rat urine using UPLC-QTOF-MSE coupled with a post-targeted screening strategy

Qi-Yu-San-Long decoction (QYSLD) is a traditional Chinese medicine that has been clinically used in the treatment of non-small-cell lung cancer (NSCLC) for more than 20 years. However, to date, metabolic-related studies on QYSLD have not been performed. In this study, a post-targeted screening strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight full information tandem mass spectrometry (UPLC-QTOF-MSE) was developed to identify QYSLD-related xenobiotics in rat urine. The chemical compound database of QYSLD constituents was established from previous research, and metabolites related to these compounds were predicted in combination with their possible metabolic pathways. The metabolites were identified by extracted ion chromatograms using predicted m/z values as well as retention time, excimer ions, and fragmentation behavior. Overall, 85 QYSLD-related xenobiotics (20 prototype compounds and 65 metabolites) were characterized from rat urine. The main metabolic reactions and elimination features of QYSLD included oxidation, reduction, decarboxylation, hydrolysis, demethylation, glucuronidation, sulfation, methylation, deglycosylation, acetylation, and associated combination reactions. Of the identified molecules, 14 prototype compounds and 58 metabolites were slowly eliminated, thus accumulating in vivo over an extended period, while five prototypes and two metabolites were present in vivo for a short duration. Furthermore, one prototype and five metabolites underwent the process of “appearing-disappearing-reappearing” in vivo. Overall, the metabolic profile and characteristics of QYSLD in rat urine were determined, which is useful in elucidating the active components of the decoction in vivo, thus providing the basis for studying its mechanism of action.

Research Progress on Metabolite Identification of Synthetic Cannabinoid New Psychoactive Substances

Synthetic cannabinoids are currently a class of new psychoactive substances with the largest variety and most abused. Metabolite identification research can provide basic data for monitoring synthetic cannabinoids abuse, which is the current research hotspot. The main trend of structural modification of synthetic cannabinoid is to replace the fluorine atom on pentyl indole or indazole cyclopentyl with hydrogen atom, which greatly improves the biological activity of the compound. The main metabolic reactions include hydroxylation, fluoropentyl oxidative, ester hydrolyze, amide hydrolysis. Liquid chromatography-high resolution mass spectrometry has become the preferred choice for the structural identification of metabolites. This review mainly summarizes research on metabolism software prediction and human hepatocyte model, human liver microsomes model, rat in vivo model, zebrafish model and fungus C. elegans model in metabolite identification based on the structure and classification of synthetic cannabinoids.

Characterization of Phase I Hepatic Metabolites of Anti-Premature Ejaculation Drug Dapoxetine by UHPLC-ESI-Q-TOF.

Determination of the metabolism pathway of xenobiotics undergoing the hepatic pass is a crucial aspect in drug development since the presence of toxic biotransformation products may result in significant side effects during the therapy. In this study, the complete hepatic metabolism pathway of dapoxetine established according to the human liver microsome assay with the use of a high-resolution LC–MS system was described. Eleven biotransformation products of dapoxetine, including eight metabolites not reported in the literature so far, were detected and identified. N-dealkylation, hydroxylation, N-oxidation and dearylation were found to be the main metabolic reactions for the investigated xenobiotic. In silico analysis of toxicity revealed that the reaction of didesmethylation may contribute to the increased carcinogenic potential of dapoxetine metabolites. On the other hand, N-oxidation and aromatic hydroxylation biotransformation reactions possibly lead to the formation of mutagenic compounds.

Characterization of metabolism feature and potential pharmacological changes of morusin-a promising anti-tumor drug-by ultra-high-performance liquid chromatography coupled time-of-flight mass spectrometry and network pharmacology

Morusin, a prenylated flavone isolated from Morus species, was treated as a potential anti-tumor drug since it inhibited effects on numerous types of human cancer cells. In some sense, drugs-related metabolites always contribute to pharmacological changes, inducing therapy improvement, reduced efficacy, or side-effects. Thus, the characterization of metabolites and the potential functions exerted great importance in clinical applications. Till now, the metabolism feature of morusin was still unclear, and its pharmacological changes were still unconducted, too. In this work, an integrated strategy based on metabolites profiling and network pharmacological was applied to characterize the metabolism feature and reveal pharmacological changes of morusin in vivo. As a result, a total of 31 metabolites (19 in plasma, 8 in urine, 30 in feces, 6 in heart, 17 in liver, 4 in spleen, 6 in lung, 6 in kidney, and 3 in brain) were screened out in rats, and 11 of them were characterized for the first time. Among them, metabolites M6, M18, M19, M20, and M28, were the main metabolites. Phase I metabolic reactions of hydroxylation, dehydrogenation (cyclization), isomerization and phase II reactions of glucuronidation occurred, and glucuronidation and hydroxylation were the two main metabolic reactions. Moreover, the pharmacological difference between morusin and five main metabolites was predicted by an network pharmacological method, and these 6 candidates targeted 177 targets. Meanwhile, in addition to common pathways (PI3K-Akt signaling pathway, proteoglycans in cancer, hepatitis B, cAMP signaling pathway, and viral carcinogenesis) of morusin in cancer, six metabolites’ targets were involved in prostate cancer, chemokine signaling pathway, ras signaling pathway and neuroactive ligand-receptor interaction, indicating that these functional changes might result in novel pharmacological mechanism and new indications. Our work provided the metabolism feature and functional modifications of morusin in vivo for the first time, and meaningful information for further pharmacological validations or potential indications in clinic were supplied.

Dissection of the potential anti-influenza materials and mechanism of Lonicerae japonicae flos based on in vivo substances profiling and network pharmacology

Lonicerae japonicae flos.(LJF) was widely used as a drug to treat upper respiratory tract infection or a tea to clear heat in Asian countries for thousands of years. Despite of its curative effects confirmed by modern pharmacological methods, its functional materials and mechanism against influenza were still unclear and needed further investigation. In this study, an integrated strategy based on in vivo substances profiling and network pharmacology was proposed and applied to screen out the potential anti-influenza substances and mechanism of LJF. An UHPLC/Q-TOF MS method was utilized to profile the chemical components in LJF and their metabolites in rats. The targets of absorbed prototypes were predicted by Swiss Target Prediction, and they were further analyzed by String and Kyoto Encyclopedia of Genes and Genomes (KEGG). As a result, a total of 126 chemical components mainly featuring three chemical structure types were characterized, including 70 iridoid glycosides, 17 caffeoylquinic acids, 24 flavonoids, and 15 other types compounds. Among them, ten N-contained iridoid glycosides were characterized as potential novel compounds. Moreover, 141 xenobiotics (74 prototypes and 67 metabolites) were clearly screened out in rat plasma and urine after ingestion of LJF. Phase II reactions (sulfation, glucuronidation, methylation) and phase I reactions (dehydroxylation, hydrogenation, hydrolysis, N-heterocyclization) were the main metabolic reactions of LJF in rats. Further, a total of 338 targets were predicted and TNF, PTGS2 and EGFR were the three main targets involved in the pathology of influenza. In addition to normal NF-κB pathway, T cell signal pathway and mTOR signal pathway were the other patterns for LJF to achieve its anti-flu effects. Our work provided the meaningful data for further pharmacological validation of LJF against influenza, and a new strategy was also proposed for minimizing the process to reveal the mechanism and functional basis of TCMs.

Toxicokinetic Studies and Analytical Toxicology of the New Synthetic Opioids Cyclopentanoyl-Fentanyl and Tetrahydrofuranoyl-Fentanyl.

The growing number of new synthetic opioids (NSO) on the new psychoactive substances (NPS) market bears new challenges in toxicology. As their toxicodynamics and particularly their toxicokinetics are usually unknown, impact on human health is not yet fully understood. Detection of the 2 NSO cyclopentanoyl-fentanyl (CP-F) and tetrahydrofuranoyl-fentanyl (THF-F) was first reported in 2016. Both were involved in several fatal intoxication cases, but no detailed information about their toxicological characteristics is available so far. The main purpose of this study was therefore to investigate the in vitro toxicokinetics and in vivo analytical toxicology of CP-F and THF-F by means of liquid chromatography high-resolution tandem mass spectrometry (LC-HRMS/MS). These studies included metabolic stability, phase I and II metabolism, isozyme mapping, plasma protein binding and detectability in LC-HRMS/MS standard urine screening approaches (SUSA) using rat urine samples. In total, 12 phase I metabolites of CP-F and 13 of THF-F were identified, among them 9 metabolites described for the first time. Overall, N-dealkylations, hydroxylations and dihydroxylations were the main metabolic reactions. The cytochrome P450 (CYP) isozymes mainly involved were CYP2D6 and CYP3A4, leading to elevated drug levels and intoxications in CYP2D6 poor metabolizers. CP-F showed a high plasma protein binding of 99%, which may increase the risk of toxicity by simultaneous intake of other highly bound drugs. Detectability studies showed that neither the parent compounds nor their metabolites were detectable in rat urine using LC-HRMS/MS SUSA. However, a more sophisticated analytical strategy was successfully applied and should be used for analytical confirmation of an intake of CP-F and/or THF-F.

Method validation and preliminary pharmacokinetic studies on the new designer stimulant 3-fluorophenmetrazine (3-FPM).

Pharmaceutical research not only provides the basis for the development of new medicinal products but also for the synthesis of new drugs of abuse. 3-Fluorophenmetrazine (3-FPM), a fluorinated derivative of the anorectic phenmetrazine, was first patented in 2011 and appeared on the drug market in 2014. Though invented for potential medical purposes, pharmacokinetic data on this compound, crucial for interpreting forensic as well as clinical cases, are not available. Therefore, a liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) method for the detection of 3-FPM in serum, urine, and oral fluid was developed, validated for urine and serum, and used to quantify 3-FPM in samples obtained during a controlled self-experiment. The method proved to be linear, selective and sufficiently sensitive. The limits of detection (LODs) were 0.1ng/mL, 0.2ng/mL, and 0.05ng/mL in serum, urine, and oral fluid. Inter-day precision and intra-day precision (RSD) in serum samples were below 6.3% and below 8.5%, respectively. The highest serum concentration (cmax ) of 210ng/mL was reached 2.5hours (tmax ) after ingestion. The elimination half-life and the volume of distribution were calculated to be approx. 8.8hours and 400L (5.3L/kg). 3-FPM could be detected in serum and urine up to 82hours and 116hours, respectively. It was still detected in the last oral fluid sample taken 55hours after ingestion. 3-FPM was mainly excreted unchanged. Main metabolic reactions were aryl-hydroxylation and N-hydroxylation. Interestingly, the product of oxidative ring opening (2-amino-1-(3-fluorophenyl)propan-1-ol) showed the largest window of detection in the self-experiment.

Relationship of heme c, nitrogen loading capacity and temperature in anammox reactor

The characteristic carmine red color due to heme proteins is always observed in enriched anammox biomass. Heme c is a very important co-factor participating the main metabolic reactions with catalytic and electron-transfer potential in the anammox bacteria, and is possible for use as an indicator to evaluate anammox performance. Knowledge of the relationship between the heme c concentration and the anammox reactor performance is, however, very limited available information is constrained at an operation temperature of 35 °C. In this study, we report the heme c concentration change along with nitrogen removal rate (NRR) in three anammox expanded granular sludge bed reactors operated at different temperatures (15, 25, 35 °C). The response of specific anammox activity (SAA) to temperature was revealed for biomass originating from three reactors. The results indicate a strong relationship between heme c concentration and NRR at different culture temperatures. The possibility of evaluating the anammox performance by combining heme c quantification and the temperature is revealed.

Investigation of the In Vivo Metabolism of Sibirioside A and Angoroside C in Rats by HPLC-ESI-IT-TOF-MSn.

Sibirioside A and angoroside C are two important phenylpropanoid glycosides of the traditional Chinese medicine Scrophulariae Radix. High performance liquid chromatography, coupled with an ion trap time-of-flight multistage mass spectrometry equipped with electrospray ionization source (HPLC-ESI-IT-TOF-MSn), was applied to the profile and we identified the metabolites of sibirioside A and angoroside C in vivo in rats. A total of four metabolites of sibirioside A were identified: SM1, SM2 and SM3 which were known as new compounds. A total of 25 metabolites were detected for angoroside C: AM4, AM5, AM6, AM7, AM16, AM17, AM20, AM21, AM22, AM23 and AM25 which were identified to be new compounds. The main metabolic reactions were hydrolysis, reduction, hydroxylation, methylation, sulfation, and gluconylation. The prototype of sibirioside A was widely distributed in tissues found in the heart, liver, spleen, lung, kidney, stomach and small intestine of rats, and mainly distributed in the stomach, small intestine, kidney and liver. But for angoroside C, nothing was found in the viscera except the stomach and small intestine. The metabolites of sibirioside A were mainly eliminated from feces, while it was urine for the metabolites of angoroside C. Furthermore, 19 metabolites were likely to have bioactivities based on the ‘PharmMapper’ analysis, which roughly matched the known pharmacological activities of Scrophulariae Radix (SR) and the prototypes. One of the main pharmacological activities of SR in traditional Chinese medicine is anti-diabetes, and the predicted results showed that SM1, SM2, SM3, AM2, AM4, AM5, AM6, AM9, AM10, AM11, AM12, AM13, AM15, AM18, AM19, AM24, and AM25 might be used to cure diabetes. These findings provide a reference for studying the metabolism, distribution and pharmacological actions of phenylpropanoid glycosides in vivo.

Systematic screening and characterization of Qi-Li-Qiang-Xin capsule-related xenobiotics in rats by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry

Qi-Li-Qiang-Xin capsule (QLQX), a well-known traditional Chinese medicine prescription (TCMP), is consisted of eleven commonly used herbal medicines, has been widely used for the treatment of chronic heart failure (CHF). However, the absorbed components and related metabolites after oral administration of QLQX are still remaining unknown. In the present work, a reliable and effective method using ultra performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) was established to identify QLQX-related xenobiotics in rats. Based on a representative structure based homologous xenobiotics identification (RSBHXI) strategy, a total of eleven compounds (salvianolic acid B, formononetin, benzoylmesaconine, alisol A, sinapine thiocyanate, naringin, tanshinone IIA, ginsenoside Rg1, ginsenoside Rb1, astragaloside IV and periplocin), bearing different chemical core structures, were selected and investigated for their metabolism in vivo. And then, comprehensive metabolic profiles of the holistic multi-ingredients in QLQX were achieved. As a result, a total of 121 QLQX-related xenobiotics (47 prototypes and 74 metabolites) were identified or tentatively characterized, among them eight prototypes (mesaconine, hypaconine, songorine, fuziline, neoline, talatizamine formononetin, neocryptotanshinone) and two metabolites (calycosin-gluA, formononetin-guA) were relatively the main existing xenobiotics exposed in blood. All absorbed prototype constituents were mainly from six composed herbal medicines (Aconiti lateralis radix, Astragali radix, Ginseng radix, Alismatis rhizoma, Salvia miltiorrhiza radix, Periploca cortex). The main metabolic reactions were methylation, hydrogenation, hydroxylation, oxidization, sulfation and glucuronidation. This is the first study on in vivo metabolism of QLQX. These results enabled us to focus on several high exposure ingredients in the discovery of effective substances of QLQX, however further pharmacokinetic study on these QLQX-related xenobiotics are needed to be carried out.

Metabolites profile of Gualou Xiebai Baijiu decoction (a classical traditional Chinese medicine prescription) in rats by ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry

Gualou Xiebai Baijiu decoction (GLXB), a well-known classic traditional Chinese medicine prescription, has been widely used to treat coronary heart diseases for thousands of years in Eastern Asian countries due to its remarkable clinical effect. However, due to lack of in vivo metabolism research, the chemical components responsible for the therapeutic effects still remain unclear. In this work, a reliable “representative structure based homologous xenobiotics identification” (RSBHXI) strategy based on ultra-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (UPLC/Q-TOF-MS) were applied to investigate the chemical components in GLXB extracts. As a result, 133 chemical components were characterized based on summarized fragmentation patterns, of which 41 components were confirmed unambiguously with authentic standards. Furthermore, a total of 138 GLXB-related xenobiotics were identified or tentatively characterized after oral administration of GLXB extracts. Moreover, to better understand the metabolic pathways of characteristic components in GLXB, metabolites profiles of five steroidal saponins and two flavonoids were performed, respectively. Since the metabolic pathways of five representative saponins had been finished in our previous study, we focused on the in vivo metabolism of two flavonoids. A total of 36 and 20 metabolites were detected in rat biological samples after oral administration of luteolin-7-O-β-D-glucopyranoside and rutin, respectively. The results indicated that dehydration, hydrolysis, hydroxylation, methylation, glucuronidation and sulfation were the main metabolic reactions, following the metabolic soft spots of GLXB-related flavonoids. Taken altogether, this study would be helpful for the further pharmacokinetics, pharmacological evaluation and quality control of GLXB.

Biotransformation of (+)-Carvone and (-)-Carvone by the Common Cutworm Spodoptera litura Larvae.

Biotransformation of (+)- and (-)-carvone (1 and 2) by the larvae of common cutworm (Spodoptera litura) has been investigated. (+)-Carvone was transformed to (+)-(4S)-10-hydroxycarvone (1-1), (+)-(4S)-7- hydroxycarvone (1-2), and (-)-(4S)-8,9-dihydroxy-8,9-dihydrocarvone (1-3). (-)-Carvone (2) was transformed to (-)-(4R)-10-hydroxycarvone (2-1), (-)-(4R)-7-hydroxycarvone (2-2), (+)-(4R)-8,9-dihydroxy-8,9- dihydrocarvone (2-3), and (-)-(2R,4R)-10-hydroxycarveol (2-4). The results indicate that the main metabolic reaction of carvones by S. litura larvae is oxidation at vinyl group (C-8 and C-9).

LC-high resolution-MS/MS for identification of 69 metabolites of the new psychoactive substance 1-(4-ethylphenyl-)-N-[(2-methoxyphenyl)methyl] propane-2-amine (4-EA-NBOMe) in rat urine and human liver S9 incubates and comparison of its screening power with further MS techniques.

4-EA-NBOMe (N-(2-methoxybenzyl)-4-ethylamphetamine, 1-(4-ethylphenyl-)-N-[(2-methoxyphenyl)methyl]propane-2-amine) is an amphetamine-derived new psychoactive substance (NPS) of the N-methoxybenzyl (NBOMe) group first seized by German custom authorities. In contrast to the phenethylamine NBOMes, studies on the pharmacological, toxicological, or metabolic properties are not yet published. The aims of the presented work were the use of LC-HR-MS/MS for identification of the phase I and II metabolites of 4-EA-NBOMe in rat urine and pooled human S9 fraction (pS9) incubations, to compare metabolite formation in both models, to identify involved monooxygenases, and to elucidate its detectability in standard urine screening approaches (SUSAs) using GC-MS, LC-MSn, and LC-HR-MS/MS. 4-EA-NBOMe was mainly metabolized by oxidation of the ethyl group to phenyl acetaldehyde, to benzoic acid, or to phenylacetic acid, by hydroxylation, and all combined with O-demethylation as well as by glucuronidation and sulfation of the main phase I metabolites in rats. With the exception of the oxidation to benzoic acid, all main metabolic reactions could be confirmed in the incubations with pS9. In total, 36 phase I and 33 phase II metabolites could be identified. Monooxygenase activity screenings revealed the general involvement of cytochrome-P450 (CYP) 1A2, CYP2B6, and CYP3A4. An intake of 4-EA-NBOMe was detectable only via its metabolites by all SUSAs after low-dose administration. The main targets for both LC-MS screenings should be the phenylacetic acid derivative, the mandelic acid derivative both with and without additional O-demethylation, and, for GC-MS, the hydroxy metabolite after conjugate cleavage.

Metabolite profiling of carbamazepine and ibuprofen in Solea senegalensis bile using high-resolution mass spectrometry

The widespread occurrence of pharmaceuticals in the aquatic environment has raised concerns about potential adverse effects on exposed wildlife. Very little is currently known on exposure levels and clearance mechanisms of drugs in marine fish. Within this context, our research was focused on the identification of main metabolic reactions, generated metabolites, and caused effects after exposure of fish to carbamazepine (CBZ) and ibuprofen (IBU). To this end, juveniles of Solea senegalensis acclimated to two temperature regimes of 15 and 20 °C for 60 days received a single intraperitoneal dose of these drugs. A control group was administered the vehicle (sunflower oil). Bile samples were analyzed by ultra-high-performance liquid chromatography–high-resolution mass spectrometry on a Q Exactive (Orbitrap) system, allowing to propose plausible identities for 11 metabolites of CBZ and 13 metabolites of IBU in fish bile. In case of CBZ metabolites originated from aromatic and benzylic hydroxylation, epoxidation, and ensuing O-glucuronidation, O-methylation of a catechol-like metabolite was also postulated. Ibuprofen, in turn, formed multiple hydroxyl metabolites, O-glucuronides, and (hydroxyl)-acyl glucuronides, in addition to several taurine conjugates. Enzymatic responses after drug exposures revealed a water temperature-dependent induction of microsomal carboxylesterases. The metabolite profiling in fish bile provides an important tool for pharmaceutical exposure assessment.Graphical abstractStudies of metabolism of carbamazepine and ibuprofen in fish

Metabolism of the tryptamine-derived new psychoactive substances 5-MeO-2-Me-DALT, 5-MeO-2-Me-ALCHT, and 5-MeO-2-Me-DIPT and their detectability in urine studied by GC-MS, LC-MSn , and LC-HR-MS/MS.

Many N,N-dialkylated tryptamines show psychoactive properties and were encountered as new psychoactive substances. The aims of the presented work were to study the phase I and II metabolism and the detectability in standard urine screening approaches (SUSA) of 5-methoxy-2-methyl-N,N-diallyltryptamine (5-MeO-2-Me-DALT), 5-methoxy-2-methyl-N-allyl-N-cyclohexyltryptamine (5-MeO-2-Me-ALCHT), and 5-methoxy-2-methyl-N,N-diisopropyltryptamine (5-MeO-2-Me-DIPT) using gas chromatography-mass spectrometry (GC-MS), liquid chromatography coupled with multistage accurate mass spectrometry (LC-MSn ), and liquid chromatography-high-resolution tandem mass spectrometry (LC-HR-MS/MS). For metabolism studies, urine was collected over a 24h period after administration of the compounds to male Wistar rats at 20mg/kg body weight (BW). Phase I and II metabolites were identified after urine precipitation with acetonitrile by LC-HR-MS/MS. 5-MeO-2-Me-DALT (24 phase I and 12 phase II metabolites), 5-MeO-2-Me-ALCHT (24 phase I and 14 phase II metabolites), and 5-MeO-2-Me-DIPT (20 phase I and 11 phase II metabolites) were mainly metabolized by O-demethylation, hydroxylation, N-dealkylation, and combinations of them as well as by glucuronidation and sulfation of phase I metabolites. Incubations with mixtures of pooled human liver microsomes and cytosols (pHLM and pHLC) confirmed that the main metabolic reactions in humans and rats might be identical. Furthermore, initial CYP activity screenings revealed that CYP1A2, CYP2C19, CYP2D6, and CYP3A4 were involved in hydroxylation, CYP2C19 and CYP2D6 in O-demethylation, and CYP2C19, CYP2D6, and CYP3A4 in N-dealkylation. For SUSAs, GC-MS, LC-MSn , and LC-HR-MS/MS were applied to rat urine samples after 1 or 0.1mg/kg BW doses, respectively. In contrast to the GC-MS SUSA, both LC-MS SUSAs were able to detect an intake of 5-MeO-2-Me-ALCHT and 5-MeO-2-Me-DIPT via their metabolites following 1mg/kg BW administrations and 5-MeO-2-Me-DALT following 0.1mg/kg BW dosage. Copyright © 2017 John Wiley & Sons, Ltd.

Identification of in vitro and in vivo metabolites of alantolactone by UPLC-TOF-MS/MS.

Alantolactone (AL), an active sesquiterpene originating from Inula helenium, is a potential anticancer and anti-inflammatory agent. However so far, studies on AL metabolism have not been reported. In the present study, we have investigated for the first time the in vivo and in vitro metabolites of AL using ultra performance liquid chromatography combined with time of flight mass spectrometry (UPLC-TOF-MS/MS). A unique on-line information-dependent acquisition (IDA) method multiple mass defect filter (MMDF) combined with dynamic background subtraction (DBS) was applied to trace all of the probable metabolites of AL. Five MMDF templates were set according to the core structure of AL and the general metabolite biotransformation patterns, and other five sulfur-containing dimer filter templates were first established on the basis of structural elucidation of AL metabolites obtained from rat intestinal bacteria biotransformation. As a result, 44 metabolites were characterized: 41 metabolites from rat urine, bile and feces after oral administration of AL, and 13 metabolites from AL biotransformation by rat intestinal bacteria. Particularly, 26 metabolites were identified as novel sulfur-containing products. The results indicated that addition of double bond at Δ((11,13)) and oxidization were the main metabolic reactions of AL. A new metabolism pathway to produce addition products of H2S to AL and further generate a series of sulfur-containing dimers of AL was revealed. This study significantly enriched our knowledge about AL metabolism, which will lead to a better understanding of the safety and efficacy of AL. At the same time, the established methodology can be widely applied for the structural determination of the metabolites of other sesquiterpene containing α-methylene-γ-lactone moiety.