Liquid Chromatography-electron Spray Ionization-mass Spectrometry Research Articles

Antifungal metabolites produced by Pseudomonas hunanensis SPT26 effective in biocontrol of fusarium wilt of Lycopersicum esculentum under saline conditions.

In past few years, salinity has become one of the important abiotic stresses in the agricultural fields due to anthropogenic activities. Salinity is leading towards yield losses due to soil infertility and increasing vulnerability of crops to diseases. Fluorescent pseudomonads are a diverse group of soil microorganisms known for promoting plant growth by involving various traits including protecting crops from infection by the phytopathogens. In this investigation, salt tolerant plant growth promoting bacterium Pseudomonas hunanensis SPT26 was selected as an antagonist against Fusarium oxysporum, causal organism of fusarium wilt in tomato. P. hunanensis SPT26 was found capable to produce various antifungal metabolites. Characterization of purified metabolites using Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography-electron spray ionization-mass spectrometry(LC-ESI/MS) showed the production of various antifungal compounds viz., pyrolnitrin, pyochelin and hyroxyphenazine by P. hunanensis SPT26. In the preliminary examination, biocontrol activity of purified antifungal metabolites was checked by dual culture method and results showed 68%, 52% and 65% growth inhibition by pyrolnitrin, 1- hydroxyphenazine and the bacterium (P. hunanensis SPT26) respectively. Images from scanning electron microscopy (SEM) revealed the damage to the mycelia of fungal phytopathogen due to production of antifungal compounds secreted by P. hunanensis SPT26. Application of bioinoculant of P. hunanensis SPT26 and purified metabolites significantly decreased the disease incidence in tomato and increased the plant growth parameters (root and shoot length, antioxidant activity, number of fruits per plant, etc.) under saline conditions. The study reports a novel bioinoculant formulation with the ability to promote plant growth parameters in tomato in presence of phytopathogens even under saline conditions.

Oriental melon roots metabolites changing response to the pathogen of Fusarium oxysporum f. sp. melonis mediated by Trichoderma harzianum

IntroductionTrichoderma spp. is a recognized bio-control agent that promotes plant growth and enhances resistance against soil-borne diseases, especially Fusarium wilt. It is frequently suggested that there is a relationship between resistance to melon wilt and changes in soil microbiome structures in the rhizosphere with plant metabolites. However, the exact mechanism remains unclear.MethodThis study aims to investigate the effects of Trichoderma application on the metabolic pathway of oriental melon roots in response to Fusarium oxysporum f. sp. melonis in a pot experiment. The experiment consisted of three treatments, namely water-treated (CK), FOM-inoculated (KW), and Trichoderma-applied (MM) treatments, that lasted for 25 days. Ultra-performance liquid chromatography-electron spray ionization-mass spectrometry (UPLC-ESI-MS) was used to analyze the compounds in melon roots.ResultsThe results show that Trichoderma harzianum application resulted in a reduction in the severity of oriental melon Fusarium wilt. A total of 416 distinct metabolites, categorized into four groups, were detected among the 886 metabolites analyzed. Additionally, seven differential metabolites were identified as key compounds being accumulated after inoculation with Fusarium oxysporum f. sp. melonis (FOM) and Trichoderma. The mechanism by which Trichoderma enhanced melon's resistance to Fusarium wilt was primarily associated with glycolysis/gluconeogenesis, phenylpropanoid biosynthesis, flavone and flavonol biosynthesis, and the biosynthesis of cofactors pathway. In comparison with the treatments of CK and MM, the KW treatment increased the metabolites of flavone and flavonol biosynthesis, suggesting that oriental melon defended against pathogen infection by increasing flavonol biosynthesis in the KW treatment, whereas the application of Trichoderma harzianum decreased pathogen infection while also increasing the biosynthesis of glycolysis/gluconeogenesis and biosynthesis of cofactors pathway, which were related to growth. This study also aims to enhance our understanding of how melon responds to FOM infection and the mechanisms by which Trichoderma harzianum treatment improves melon resistance at the metabolic level.

Determination of 14 Isoflavone Isomers in Natto by UPLC-ESI-MS/MS and Antioxidation and Antiglycation Profiles.

Natto is a famous traditional fermented food, but the influence of the fermentation process on the content and composition of soybean isoflavones and nutritional value is still unclear. In the present study, the variation in soybean isoflavones during fermentation by Bacillus subtilis natto was revealed by UPLC-ESI-MS/MS (Ultra high performance liquid chromatography-electron spray ionization-mass spectrometry) analysis. After 24 h of fermentation, the total isoflavone content in natto increased by 1.62 times compared with fresh soybean, and the content of aglycones was 3.07 times that of raw beans. More importantly, among 14 isoflavone isomers identified in natto, the isomers of daidzin, genistin, and succinyl genistin were detected for the first time, which might be due to the result of isomerase and succinylase and other corresponding enzymes’ action in Bacillus subtilis. In addition, natto isoflavones performed great antioxidant activity than its monomer components (glycosides daidzin and genistin, aglycones genistein and daidzein), except for genistein. Moreover, natto isoflavone and its aglycones (especially genistein) performed great inhibitory activity against AGEs (Advanced Glycation End Products) in three in vitro models. The mechanism test showed that genistein could form adducts (UPLC-Q-TOF-ESI-MS/MS analysis) with methylglyoxal. These findings demonstrated that soybean fermented with Bacillus subtilis natto had a significant influence on the isoflavone profiles and its bioactivity.

Development and validation of HPLC-DAD and LC-(ESI)/MS methods for the determination of sulfasalazine, mesalazine and hydrocortisone 21-acetate in tablets and rectal suppositories: In vitro and ex vivo permeability studies

Controlled-release tablets and rectal suppositories of sulfasalazine (SLF) and hydrocortisone 21-acetate (HA) were prepared as recommended dosage forms for the treatment of acute episodes of ulcerative colitis, in patients who do not respond to monotherapy.A High-Performance Liquid Chromatography (HPLC) Diode-array method with a gradient elution mobile phase was developed to evaluate the production quality of both formulations (assay and dissolution profiles in gastric and intestinal fluids). Method's validation was carried out providing good linearity (r ≥ 0.9995), precision (RSD < 1.53%), recovery (96.9% − 103.7%) and limits of detection (LODSLF = 12 ng/mL, LODHA = 15 ng/mL). Experimental design and Plackett-Burman methodology was constructed to study the robustness of the analysis. In all composite substrates, a freezing lipid precipitation approach was used as purification step. The method was optimized by applying Central Composite design mode.The in-vitro/ex-vivo permeability studies of both formulations were evaluated by a Liquid Chromatography-Electron Spray Ionization Mass Spectrometry (LC-ESI/MS) +/- mode. The analysis of sulfamethazine (internal standard, SLM, m/z 279), HA (m/z 449, [M + HCOO]-), SLF (m/z 399) and its active metabolite mesalazine (MSL, m/z 154) was performed using a C18 column and gradient elution. The validation of the method met the requirements of the International Council for Harmonization (ICH) (r ≥ 0.9997, RSD ≤ 4.62%, Recovery > 95%, LODSLF = 1.28 ng/mL, LODHA = 1.07 ng/mL, LODMSL = 3.16 ng/mL). Based on the results, important conclusions were drawn concerning the role of excipients and SLF metabolism.

Widely targeted metabolomics analysis reveals the effect of fermentation on the chemical composition of bee pollen

Microbial fermentation can break the bee pollen wall. However, the global profiling of bee pollen metabolites under fermentation remains unclear. This study aims to comprehensively elucidate the changes in the composition of bee pollen after microbial fermentation. Ultra-performance liquid chromatography-electron spray ionization-mass spectrometry (UPLC-ESI-MS) based on widely targeted metabolomics analysis was used to compare the chemical composition of unfermented bee pollen (UBP) and fermented bee pollen (FBP). Among the 890 metabolites detected, a total of 668 differential metabolites (classified into 17 categories) were identified between UBP and FBP. Fermentation significantly increased the contents of primary metabolites such as 74 amino acids and derivatives, 42 polyunsaturated fatty acids and 66 organic acids, as well as some secondary metabolites such as 38 phenolic acids, 80 flavone aglycones and 22 phenolamides. The results indicate that fermentation is a promising strategy to improve the nutritional value of bee pollen.

Bioactive Molecules for Discriminating Robinia and Helianthus Honey: High-Performance Liquid Chromatography-Electron Spray Ionization-Mass Spectrometry Polyphenolic Profile and Physicochemical Determinations.

Bioactive molecules from the class of polyphenols are secondary metabolites from plants. They are present in honey from nectar and pollen of flowers from where honeybees collect the “raw material” to produce honey. Robinia pseudoacacia and Helianthus annuus are important sources of nectar for production of two monofloral honeys with specific characteristics and important biological activity. A high-performance liquid chromatography–electro spray ionization–mass spectrometry (HPLC–ESI–MS) separation method was used to determine polyphenolic profile from the two types of Romanian unifloral honeys. Robinia and Helianthus honey showed a common flavonoid profile, where pinobanksin (1.61 and 1.94 mg/kg), pinocembrin (0.97 and 1.78 mg/kg) and chrysin (0.96 and 1.08 mg/kg) were identified in both honey types; a characteristic flavonoid profile in which acacetin (1.20 mg/kg), specific only for Robinia honey, was shown; and quercetin (1.85 mg/kg), luteolin (21.03 mg/kg), kaempferol (0.96 mg/kg) and galangin (1.89 mg/kg), specific for Helianthus honey, were shown. In addition, different phenolic acids were found in Robinia and Helianthus honey, while abscisic acid was found only in Robinia honey. Abscisic acid was correlated with geographical location; the samples collected from the south part of Romania had higher amounts, due to climatic conditions. Acacetin was proposed as a biochemical marker for Romanian Robinia honey and quercetin for Helianthus honey.

Product enhancement of triterpenoid saponins in cell suspension cultures of Leucas aspera Spreng

The present investigation reports the influence of signaling molecules methyl jasmonate (MeJA) and salicylic acid (SA) on enhanced production of triterpenoid saponins ursolic acid and oleanolic acid in cell suspension cultures of Leucas aspera Spreng. Callus was initiated in leaf explants of L. aspera on MS (Murashige and Skoog) medium supplemented with 2 mg L-1 2,4-D (2,4-dichlorophenoxyacetic acid) and 0.2 mg L-1 picloram. Callus was transferred to MS liquid medium supplemented with 2 mg L-1 2,4-D and 0.2 mg L-1 picloram for the initiation of cell suspension culture. Influence of elicitors MeJA and SA on the biosynthesis of triterpenoids was investigated to assess whether elicitor-mediated production would serve as an alternative strategy for the over production of Leucas aspera triterpenoids. Elicitors were supplemented at different concentrations (50, 100 and 200 μM) in the suspension cultures for 24 days with 6 days intervals. Loss of cell viability was observed at high concentrations of elicitors. MeJA exhibited a maximum level of total saponin content (18.2 ± 1.21 mg g-1 DCW) at 100 μM concentration over a period of 18 days and is 4 folds higher than the respective non-elicited control. While SA at 50 μM concentration showed highest production of total saponins (15 ± 1.21 mg g-1 DCW) after 24 days of exposure and is 1.68 fold higher than the respective non-elicited control. There is an inverse relationship observed between saponins production to the biomass accumulation. Results of TLC (Thin layer chromatography), HPLC (High performance liquid chromatography), LC-ESI-MS (Liquid chromatography-Electron spray ionization-Mass spectrometry) and FT-IR (Fourier Transform Infrared spectroscopy) analyses confirmed the presence of triterpenoid saponins with the dominance of oleanane and ursane classes. Cell suspension cultures elicited with MeJA (100 μM) could serve as an alternate means for the enhanced production of oleanane and ursane classes of triterpenoids which bear pharmaceutical importance.

Investigation of gilding materials and techniques in wall paintings of Kizil Grottoes

The present work reports the new characterization results of the gilding materials used in Cave 171 of Kizil Grottoes, China, which is dated between 5th and 7th Century, A.D. Tiny samples collected from four different gilding decorations were analyzed by scanning electron microscopy with element energy dispersive X-ray spectroscopy (SEM-EDS) to identify the gilding structure and inorganic materials. It was discovered that both tin and gold leaves were used as the gilding foils. Interestingly, different organic mordants were used under different foils. The pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) results show that drying oil was applied as the mordant for the adhesion of tin foils while lac resin was used for gold foils. The presence of lac resin has been further confirmed by liquid chromatography-electron spray ionization-mass spectrometry (LC-ESI-MS). Although lac dye has been detected as the red colorant in wall paintings of Buddhist grottoes, its use as gilding mordant is a new finding. These gilding materials found in the wall paintings of Kizil Grottoes may provide some evidence of painting materials and techniques exchange along the Silk Road.

Variability of Bioactive Glucosinolates, Isothiocyanates and Enzyme Patterns in Horseradish Hairy Root Cultures Initiated from Different Organs.

Horseradish hairy root cultures are suitable plant tissue organs to study the glucosinolate–myrosinase–isothiocyanate system and also to produce the biologically active isothiocyanates and horseradish peroxidase, widely used in molecular biology. Fifty hairy root clones were isolated after Agrobacterium rhizogenes infection of surface sterilized Armoracia rusticana petioles and leaf blades, from which 21 were viable after antibiotic treatment. Biomass properties (e.g., dry weight %, daily growth index), glucosinolate content (analyzed by liquid chromatography-electronspray ionization-mass spectrometry (LC-ESI-MS/MS)), isothiocyanate and nitrile content (analyzed by gas chromatography-mass spectrometry (GC-MS)), myrosinase (on-gel detection) and horseradish peroxidase enzyme patterns (on-gel detection and spectrophotometry), and morphological features were examined with multi-variable statistical analysis. In addition to the several positive and negative correlations, the most outstanding phenomenon was many parameters of the hairy root clones showed dependence on the organ of origin. Among others, the daily growth index, sinigrin, glucobrassicin, 3-phenylpropionitrile, indole-3-acetonitrile and horseradish peroxidase values showed significantly higher levels in horseradish hairy root cultures initiated from leaf blades.

Fluconazole Inhibits Cytochrome P450 1B1 and its Associated Arachidonic Acid Metabolites in the Heart and Protects against Angiotensin II‐induced Cardiac Hypertrophy

Cytochrome P450 1B1 (CYP1B1) has been reported to have a major role in metabolizing arachidonic acid (AA) into cardiotoxic metabolites, mid‐chain hydroxyeicosatetraenoic acid (HETEs). Of particular interest, several studies have demonstrated the role of mid‐chain HETEs in the development of cardiac hypertrophy. Recently, we have shown that fluconazole inhibits the formation of mid‐chain HETEs metabolite, however, whether fluconazole would be able to modulate CYP1B1‐mediated AA metabolism in an Ang II‐induced cellular hypertrophy model and in rats' heart has never been investigated before. Therefore, the objectives of this study were; 1) to investigate the effect of fluconazole on CYP1B1 mediated AA metabolites and to explore the potential protective effect against Ang II‐induced cellular hypertrophy, and 2) to study the effect of fluconazole on CYP1B1 and its associated AA metabolites in vivo in Sprague Dawley rats. For this purpose, both H9c2 and RL‐14 cells were treated with 10 μM Ang II in the absence and presence of 50 μM fluconazole for 24 hours. Also, Sprague Dawley rats (n=6) were injected intraperitoneally with a single dose of fluconazole (20 mg/kg) or saline and the heart tissues were harvested 24 hours post‐treatment. Thereafter, the formation of AA metabolites was measured using liquid chromatography‐electron spray ionization‐mass spectrometry (LC‐ESI‐MS). Whereas, the expression of cardiac hypertrophic markers and CYP1B1 were determined by real time‐polymerase chain reaction and Western blot analysis, respectively. Moreover, enzymatic activity and determination of CYP1B1 inhibition kinetics by fluconazole were assessed using 7‐ethoxyresorufin O‐deethylase (EROD) and recombinant human CYP1B1 assays. Our results demonstrated that fluconazole was able to attenuate Ang‐II‐induced cellular hypertrophy as evidenced by a significant inhibition of hypertrophic markers, β‐myosin heavy chain (MHC)/ α‐MHC, BNP as well as cell surface area. The protective effect of fluconazole was associated with a significant decrease in the level of CYP1B1 gene, protein, activity levels and its associated mid‐chain HETEs metabolite induced by Ang II. Furthermore, treatment of rats with fluconazole significantly decreased the expression of CYP1B1 enzyme and the formation level of cardiotoxic mid‐chain HETEs metabolites in the heart. In conclusion, our results showed that fluconazole protects against Ang II‐induced cellular hypertrophy by inhibiting CYP1B1 and its associated mid‐chain HETEs metabolites. Also, fluconazole may be repurposed as a mid‐chain HETEs formation inhibitor for the treatment of cardiac hypertrophy and heart failure.Support or Funding InformationThis work was supported by a grant from the Canadian Institutes of Health Research [Grant 106665] to A.O.S.E. A.H.A is the recipient of Saudi Arabian government scholarship provided by Qassim University.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

CYP1B1 inhibition attenuates doxorubicin-induced cardiotoxicity through a mid-chain HETEs-dependent mechanism

Doxorubicin (DOX) has been reported to be a very potent and effective anticancer agent. However, clinical treatment with DOX has been greatly limited due to its cardiotoxicity. Furthermore, several studies have suggested a role for cytochrome P450 1B1 (CYP1B1) and mid-chain hydroxyeicosatetraenoic acids (mid-chain HETEs) in DOX-induced cardiac toxicity. Therefore, we hypothesized that DOX induced cardiotoxicity is mediated through the induction of CYP1B1 and its associated mid-chain HETEs metabolite. To test our hypothesis, Sprague-Dawley rats and RL-14 cells were treated with DOX in the presence and absence of 2,3′,4,5′-tetramethoxystilbene (TMS), a selective CYP1B1 inhibitor. Thereafter, cardiotoxicity parameters were determined using echocardiography, histopathology, and gene expression. Further, the level of mid-chain HETEs was quantified using liquid chromatography-electron spray ionization-mass spectrometry. Our results showed that DOX induced cardiotoxicity in vivo and in vitro as evidenced by deleterious changes in echocardiography, histopathology, and hypertrophic markers. Importantly, the TMS significantly reversed these changes. Moreover, the DOX-induced cardiotoxicity was associated with a proportional increase in the formation of cardiac mid-chain HETEs both in vivo and in our cell culture model. Interestingly, the inhibition of cardiotoxicity by TMS was associated with a dramatic decrease in the formation of cardiac mid-chain HETEs suggesting a mid-chain HETEs-dependent mechanism. Mechanistically, the protective effect of TMS against DOX-induced cardiotoxicity was mediated through the inhibition of mitogen activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB). In conclusion, our study provides the first evidence that the inhibition of CYP1B1 and mid-chain HETE formation attenuate DOX-induced cardiotoxicty.

A novel high-performance liquid chromatography-electron spray ionization-mass spectrometry method for simultaneous determination of guggulsterones, piperine and gallic acid in Triphala guggulu.

“Triphalaguggulu” is an important Ayurvedic formulation comprising of Guggulu, that is, Commiphora wightii (Arn.) Bhandari as a base wherein powdered fruits of triphala, that is, Phyllanthus emblica L., Terminalia bellirica (Gaertn.) Roxb and Terminalia chebula Retz, along with powdered fruit of Piper longum L. are compounded. This polyherbal preparation has been strongly recommended in chronic inflammation, piles, and fistula. However, due to the complexity of compound formulation standardization of commercial products is challenging. In the present communication marker-based standardization of “Triphalaguggulu” preparation using gallic acid (for triphala), piperine (for P. longum L.) and guggulsterones (for guggulu) is reported. These compounds of diverse chemistry were successfully separated on a Waters HR-C18 column by isocratic elution with methanol and water (80:20 v/v) as mobile phase at the flow rate of 1.0 mL/min coupled with photodiode array detector. These optimal chromatographic conditions were used for simultaneous quantification of gallic acid, guggulsterones (E and Z) and piperine in commercial samples by high-performance liquid chromatography-electron spray ionization-mass spectrometry and method was validated as per ICH guidelines.

Human fetal ventricular cardiomyocyte, RL-14 cell line, is a promising model to study drug metabolizing enzymes and their associated arachidonic acid metabolites.

RL-14 cells, human fetal ventricular cardiomyocytes, are a commercially available cell line that has been established from non-proliferating primary cultures derived from human fetal heart tissue. However, the expression of different drug metabolizing enzymes (DMEs) in RL-14 cells has not been elucidated yet. Therefore, the main objectives of the current work were to investigate the capacity of RL-14 cells to express different cytochrome P450 (CYP) isoenzymes and correlate this expression to primary cardiomyocytes. The expression of CYP isoenzymes was determined at mRNA, protein and catalytic activity levels using real time-PCR, Western blot analysis and liquid chromatography-electron spray ionization-mass spectrometry (LC-ESI-MS), respectively. Our results showed that RL-14 cells constitutively express CYP ω-hydroxylases, CYP1A, 1B, 4A and 4F; CYP epoxygenases, CYP2B, 2C and 2J; in addition to soluble epoxide hydrolayse (EPHX2) at mRNA and protein levels. The basal expression of CYP ω-hydroxylases, epoxygenases and EPHX2 was supported by the ability of RL-14 cells to convert arachidonic acid to its biologically active metabolites, 20-hydroxyeicosatetraenoic acids (20-HETEs), 14,15-epoxyeicosatrienoic acids (14,15-EET), 11,12-EET, 8,9-EET, 5,6-EET, 14,15-dihydroxyeicosatrienoic acid (14,15-DHET), 11,12-DHET, 8,9-DHET and 5,6-DHET. Furthermore, RL-14 cells express CYP epoxygenases and ω-hydroxylase at comparable levels to those expressed in adult and fetal human primary cardiomyocytes cells implying the importance of RL-14 cells as a model for studying DMEs in vitro. Lastly, different CYP families were induced in RL-14 cells using 2,3,7,8-tetrachlorodibenzo-p-dioxin and fenofibrate at mRNA and protein levels. The current study provides the first evidence that RL-14 cells express CYP isoenzymes at comparable levels to those expressed in the primary cells and thus offers a unique in vitro model to study DMEs in the heart.

Boronic acid-functionalized detonation nanodiamond for specific enrichment of glycopeptides in glycoproteome analysis

Here we present the novel functionalization of detonation nanodiamond (dND) with amino-phenyl boronic acid (APBA) assisted by poly-L-lysine (PL) and PEG-diglycolic acid (PEG) (dND-p-APBA). With the assistance of biocompatible poly-L-lysine and PEG, dND-p-APBA particles show good dispersibility in aqueous solution and plentiful boronic acid functional groups on the surface, which make it a novel material promising for glycoproteome. The dND-p-APBA particles demonstrate highly specific and efficient capture of glycopeptides from complex samples. In comparison with direct (or traditional) analysis, the novel method shows better specificity for glycopeptides even when non-glycopeptides are 40 times more than glycopeptides. Besides that, the detection sensitivity of glycopeptides could be increased 50 times by the novel strategy. Additionally, the recovery of glycopeptides is up to 72.2% and the glycopeptides even can be sensitively specifically enriched and detected in the presence of 1 M sodium chloride or 0.1% sodium dodecyl sulfate. Furthermore, in combination with liquid chromatography electronspray ionization mass spectrometry (LC-ESI-MS), the novel approach was successfully applied to characterize one fraction of mouse liver, in which 40 different N-glycosylation peptides within 34 unique glycoproteins have been identified. Accordingly, the usefulness of the functionalized dND might be a promising efficient and specific analytical platform in glycoproteome analysis.

Quantitative Determination of Ticlopidine Hydrochloride in Human Plasma by High-performance Liquid Chromatography-Electronspray Ionization Mass Spectrometry

A sensitive, selective and simple high performance liquid chromatographyelectrospray ionization-mass spectrometry (HPLC-ESI-MS) was developed and validated for the quantification of ticlopidine hydrochloride (CAS 53885-35-1) in human plasma using loratadine (CAS 79794-75-5) as internal standard (IS). Following liquid-liquid extraction, the analyte and the IS were extracted from plasma samples by n-hexane:isopropanol (95:5, v/v), separated by HPLC on a commercially available column (150 mm x 2.0 mm ID, 5 microm) with a mobile phase of acetonitrile: 10 mmol/L ammonium acetate buffer solution (85:15, v/v) and analyzed on a quadrupole mass spectrometer with ESI interface operating in the positive-ion mode. The correlation coefficient of the calibration curve was linear (r2 > 0.99) over the concentration range of 1-1000 ng/mL for ticlopidine hydrochloride. The intra- and inter-batch precisions were less than 15% of the relative standard deviation and the accuracy ranged from 85 to 115% in terms of percent accuracy. The limit of detection (LOD) of ticlopidine hydrochloride was 0.5 ng/mL. The extraction recovery of ticlopidine hydrochloride was more than 80%. The proposed method enables the unambiguous identification and quantification of ticlopidine hydrochloride for pharmacokinetic, bioavailability or bioequivalence studies.

Acute Doxorubicin Toxicity Differentially Alters Cytochrome P450 Expression and Arachidonic Acid Metabolism in Rat Kidney and Liver

The use of doxorubicin (DOX) is limited by significant cardiotoxicity, nephrotoxicity, and hepatotoxicity. We have previously shown that DOX cardiotoxicity induces several cardiac cytochrome P450 (P450) enzymes with subsequent alteration in P450-mediated arachidonic acid metabolism. Therefore, in the current study, we investigated the effect of acute DOX toxicity on P450 expression and arachidonic acid metabolism in the kidney and liver of male Sprague-Dawley rats. Acute DOX toxicity was induced by a single intraperitoneal injection (15 mg/kg) of the drug. After 6 and 24 h, the kidneys and livers were harvested, and several P450 gene and protein expressions were determined by real-time polymerase chain reaction and Western blot analyses, respectively. Kidney and liver microsomal protein from control or DOX-treated rats was incubated with arachidonic acid, and its metabolites were determined by liquid chromatography-electron spray ionization-mass spectrometry. Our results showed that acute DOX toxicity caused an induction of CYP1B1 and CYP4A enzymes and an inhibition of CYP2B1 and CYP2C11 in both the kidney and liver. CYP2E1 was induced and soluble epoxide hydrolase (sEH) was inhibited in the kidney only. In addition, DOX toxicity caused a significant increase in epoxyeicosatrienoic acids formation in the kidney and a significant increase in 20-hydroxyeicosatetraenoic acid formation in both the kidney and the liver. In conclusion, acute DOX toxicity alters the expression of several P450 and sEH enzymes in an organ-specific manner. These changes can be attributed to DOX-induced inflammation and resulted in altered P450-mediated arachidonic acid metabolism.

Alteration of cardiac cytochrome P450-mediated arachidonic acid metabolism in response to lipopolysaccharide-induced acute systemic inflammation

Cytochrome P450 (CYP) generated cardioprotective metabolites, epoxyeicosatrienoic acids (EETs), and cardiotoxic metabolites, hydroxyeicosatetraenoic acids (HETEs) levels are determined by many factors, including the induction or repression of the CYP enzymes, responsible for their formation. Therefore, we examined the effect of acute inflammation on the expression of CYP epoxygenases and CYP omega-hydroxylases in the heart, kidney, and liver and the cardiac CYP-mediated arachidonic acid metabolism. For this purpose, male Sprague-Dawley rats were injected intraperitoneally with LPS (1mg/kg). After 6, 12, or 24h, the tissues were harvested and the expression of CYP genes and protein levels were determined using real time-PCR, and Western blot analyses, respectively. Arachidonic acid metabolites formations were determined by liquid chromatography-electron spray ionization-mass spectrometry LC-ESI-MS. Our results showed that inflammation significantly decreased the CYP epoxygenases expression in the heart, kidney and liver with a concomitant decrease in the EETs produced by these enzymes. In contrast to CYP expoxygenses, inflammation differentially altered CYP omega-hydroxylases expression with a significant increase in 20-HETE formation. The present study demonstrates for the first time that acute inflammation decreases CYP epoxygenases and their associated cardioprotective metabolites, EETs while on the other hand increases CYP omega-hydroxylases and their associated cardiotoxic metabolites, 20-HETE. These changes may be involved in the development and/or progression of cardiovascular diseases by inflammation.

3‐Methylcholanthrene and benzo(a)pyrene modulate cardiac cytochrome P450 gene expression and arachidonic acid metabolism in male Sprague Dawley rats

There is a strong correlation between cytochrome P450 (P450)-dependent arachidonic acid metabolism and the pathogenesis of cardiac hypertrophy. Several aryl hydrocarbon receptor (AhR) ligands were found to alter P450-dependent arachidonic acid metabolism. Here, we have investigated the effect of 3-methylcholanthrene (3-MC) and benzo(a)pyrene (BaP), two AhR ligands, on the development of cardiac hypertrophy. Male Sprague Dawley rats were injected (i.p.) daily with either 3-MC (10 mg kg(-1)) or BaP (20 mg kg(-1)) for 7 days. Then hearts were removed, and the heart to body weight ratio and the gene expression of the hypertrophic markers and P450 genes were determined. Levels of arachidonic acid metabolites were determined by liquid chromatography-electron spray ionization-mass spectrometry. Both 3-MC and BaP increased the heart to body weight ratio as well as the hypertrophic markers, atrial natriuretic peptide and brain natriuretic peptide. 3-MC and BaP treatment increased the gene expression of CYP1A1, CYP1B1, CYP2E1, CYP4F4, CYP4F5 and soluble epoxide hydrolase. Both 3-MC and BaP treatments increased the dihydroxyeicosatrienoic acids (DHETs) : epoxyeicosatrienoic acids (EETs) ratio and the 20-hydroxyeicosatetraenoic acid (20-HETE) : total EETs ratio. Treatment with benzo(e)pyrene, an isomer of BaP that is a poor ligand for the AhR, did not induce cardiac hypertrophy in rats, confirming the role of AhR in the development of cardiac hypertrophy. Treatment with the omega-hydroxylase inhibitor, HET0016, significantly reversed BaP-induced cardiac hypertrophy. 3-MC and BaP induce cardiac hypertrophy by increasing the ratio of DHETs : EETs and/or the ratio of 20-HETE : total EETs, through increasing soluble epoxide hydrolase activity.

Modulation of Cytochrome P450 Gene Expression and Arachidonic Acid Metabolism during Isoproterenol-Induced Cardiac Hypertrophy in Rats

Several cytochrome P450 (P450) enzymes have been identified in the heart, and their levels have been reported to be altered during cardiac hypertrophy. Moreover, there is a strong correlation between P450-mediated arachidonic acid metabolites and the pathogenesis of cardiac hypertrophy. Therefore, we investigated the effect of isoproterenol-induced cardiac hypertrophy on the expression of several P450 genes and their associated P450-derived metabolites of arachidonic acid. Cardiac hypertrophy was induced by seven daily i.p. injections of 5 mg/kg isoproterenol. Thereafter, the heart, lung, liver, and kidney were harvested, and the expression of different genes was determined by real-time polymerase chain reaction. Heart microsomal protein from control or isoproterenol treated rats was incubated with 50 microM arachidonic acid, and arachidonic acid metabolites were determined by liquid chromatography-electron spray ionization-mass spectrometry. Our results show that isoproterenol treatment significantly increased the heart/body weight ratio and the hypertrophic markers. In addition, there was a significant induction of CYP1A1, CYP1B1, CYP4A3, and soluble epoxide hydrolase and a significant inhibition of CYP2C11 and CYP2E1 in the hypertrophied hearts as compared with the control. CYP1A1, CYP2E1, and CYP4A3 gene expression was induced in the kidney, and CYP4A3 was induced in the liver of isoproterenol-treated rats. Isoproterenol treatment significantly reduced 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acid formation and significantly increased their corresponding 8,9-, and 14,15-dihydroxyeicosatrienoic acid and the 20-hydroxyeicosatetraenoic acid metabolite. In conclusion, isoproterenol-induced cardiac hypertrophy alters arachidonic acid metabolism and its associated P450 enzymes, suggesting their role in the development and/or progression of cardiac hypertrophy.