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Elmar Richter - One of the best experts on this subject based on the ideXlab platform.
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Determination of caffeine, Myosmine, and nicotine in chocolate by headspace solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry.
Journal of food science, 2014Co-Authors: Christoph Müller, Elmar Richter, F. Vetter, Franz BracherAbstract:The occurrence of the bioactive components caffeine (xanthine alkaloid), Myosmine and nicotine (pyridine alkaloids) in different edibles and plants is well known, but the content of Myosmine and nicotine is still ambiguous in milk/dark chocolate. Therefore, a sensitive method for determination of these components was established, a simple separation of the dissolved analytes from the matrix, followed by headspace solid-phase microextraction coupled with gas chromatography-tandem mass spectrometry (HS-SPME-GC-MS/MS). This is the first approach for simultaneous determination of caffeine, Myosmine, and nicotine with a convenient SPME technique. Calibration curves were linear for the xanthine alkaloid (250 to 3000 mg/kg) and the pyridine alkaloids (0.000125 to 0.003000 mg/kg). Residuals of the calibration curves were lower than 15%, hence the limits of detection were set as the lowest points of the calibration curves. The limits of detection calculated from linearity data were for caffeine 216 mg/kg, for Myosmine 0.000110 mg/kg, and for nicotine 0.000120 mg/kg. Thirty samples of 5 chocolate brands with varying cocoa contents (30% to 99%) were analyzed in triplicate. Caffeine and nicotine were detected in all samples of chocolate, whereas Myosmine was not present in any sample. The caffeine content ranged from 420 to 2780 mg/kg (relative standard deviation 0.1 to 11.5%) and nicotine from 0.000230 to 0.001590 mg/kg (RSD 2.0 to 22.1%).
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analysis of Myosmine cotinine and nicotine in human toenail plasma and saliva
Biomarkers, 2009Co-Authors: Katharina Schutteborkovec, Anne-kathrin Heling, Christopher Heppel, Elmar RichterAbstract:Myosmine is a minor tobacco alkaloid with widespread occurrence in the human diet. Myosmine is genotoxic in human cells and is readily nitrosated and peroxidated yielding reactive intermediates with carcinogenic potential. For biomonitoring of short-term and long-term exposure, analytical methods were established for determination of Myosmine together with nicotine and cotinine in plasma, saliva and toenail by gas chromatography–mass spectrometry (GC/MS). Validation of the method with samples of 14 smokers and 10 non-smokers showed smoking-dependent differences of Myosmine in toenails (66 ± 56 vs 21 ± 15 ng g−1, p <0.01) as well as saliva (2.54 ± 2.68 vs 0.73 ± 0.65 ng ml−1, p <0.01). However, these differences were much smaller than those with nicotine (1971 ± 818 vs 132 ± 82 ng g−1, p <0.0001) and cotinine (1237 ± 818 vs <35 ng g−1) in toenail and those of cotinine (97.43 ± 84.54 vs 1.85 ± 4.50 ng ml−1, p <0.0001) in saliva. These results were confirmed in plasma samples from 84 patients undergoing gast...
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Inhibition of human aromatase by Myosmine.
Drug metabolism letters, 2009Co-Authors: Irene L Doering, Elmar RichterAbstract:Myosmine, a minor tobacco alkaloid widely occurring in food products of plant and animal origin, inhibits the conversion of testosterone to estradiol by human aromatase (IC(50): 33+/-2 microM) sevenfold more potent than nicotine (IC(50): 223+/-10 microM) and may have implications for sexual hormone homoeostasis.
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evaluation of the mutagenic effects of Myosmine in human lymphocytes using the hprt gene mutation assay
Food and Chemical Toxicology, 2009Co-Authors: Joachim Havla, Courtney E. Hill, Sherif Z Abdelrahman, Elmar RichterAbstract:The minor tobacco alkaloid Myosmine is implicated in DNA damage through pyridyloxobutylation similar to the tobacco-specific nitrosamines (TSNA). In contrast to TSNA, occurrence of Myosmine is not restricted to tobacco. Myosmine is genotoxic to human cells in the comet assay. In this study, the mutagenic effect of Myosmine was evaluated using the cloning hypoxanthine-guanine phosphoribosyltransferase (HPRT) gene mutation assay. Four hour exposure of isolated peripheral blood lymphocytes from 14 subjects homozygous for the Leu84 wild-type of the O6-methylguanine-DNA-methyltransferase (MGMT) gene to 1mM of Myosmine increased mutant frequency from 0.73+/-0.58 x 10(-6) in control to 1.14+/-0.89 x 10(-6) lymphocytes (P<0.05). These new data further confirm the mutagenic effects of Myosmine.
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Evaluation of the mutagenic effects of Myosmine using the HPRT gene mutation assay
Cancer Research, 2008Co-Authors: Joachim Havla, Stefan Tyroller, Wolfgang Zwickenpflug, Elmar Richter, Courtney E. Hill, Sherif Z. Abdel-rahmanAbstract:AACR Annual Meeting-- Apr 12-16, 2008; San Diego, CA 4315 Alkylating mutagens found in tobacco such as tobacco-specific nitrosamines (TSNA) are able to form DNA adducts by methylation and/or pyridyloxobutylation. The tobacco alkaloid Myosmine, which is wide spread in human diets, also gives rise to pyridyloxobutyl DNA adducts. In contrast to TSNA requiring metabolic activation, Myosmine can be easily activated by nitrosation and peroxidation. The resulting adducts can induce DNA damage if not repaired by DNA repair machinery as shown in human lymphocytes, nasal mucosa and human cell lines using the comet assay. The direct reversal DNA repair protein, encoded by the polymorphic O6-Methylguanine-DNA-methyltransferase (MGMT) gene removes these adducts from the DNA. Three coding single nucleotide polymorphisms (cSNPs) in the MGMT gene are believed to affect MGMT function, and these, in turn, could alter the repair of such adducts. Using a modified cloning HPRT gene mutation assay, one of the most widely used somatic cell mutation assays, we determined the mutant frequency in human lymphocytes treated in vitro with Myosmine. These lymphocytes were all MGMT wild-type lymphocytes with none of the three known variants. Dose-response experiments demonstrated a strong antiproliferative effect of 1 and 5 mM Myosmine after 24 h of incubation. After incubation with 1 mM for 4 hours, viability slightly decreased by 3% (p < 0.05) but proliferation and cloning efficiency were not affected. Analysis of 14 samples after exposure to Myosmine (1 mM for 4 hours) resulted in a 56% increase in mutant frequency from 0.73±0.58 x 10-6 in control to 1.14±0.89 x 10-6 in Myosmine-treated lymphocytes (p < 0.05). These preliminary data confirm the mutagenicity of Myosmine to human lymphocytes under the tested experimental conditions. Further studies with MGMT polymorphic lymphocytes conferring impaired repair capacity, and taking into account the dependence of Myosmine activation on pH and nitrosative stress, are warranted.
Wolfgang Zwickenpflug - One of the best experts on this subject based on the ideXlab platform.
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Isolation of Nicotinic Acid (Vitamin B3) and N-Propylamine after Myosmine Peroxidation
Journal of agricultural and food chemistry, 2015Co-Authors: Wolfgang Zwickenpflug, Christof Högg, Johannes Feierfeil, Manuel Dachs, Thomas GudermannAbstract:The alkaloid Myosmine (3-(1-pyrroline-2-yl)pyridine) is widespread in biological matrixes including foodstuffs and tobacco products. Some in vitro tests in cellular systems showed mutagenic activity for Myosmine. Myosmine activation including peroxidation mechanism employs unstable oxazirane intermediates. The formation of minor metabolite 3-hydroxymethyl-pyridine in rat metabolism experiments as well as in in vitro peroxidation assays suggests its further oxidation to nicotinic acid and possible concomitant formation of n-propylamine. A sensitive high-performance liquid chromatography-ultraviolet (HPLC-UV) method was developed for the direct analysis of n-propylamine in the peroxidation assay solution of Myosmine employing derivatization with 3,5-dinitrobenzoyl chloride. Additionally, during peroxidation procedures, formation of 3-pyridylmethanol to nicotinic acid, the essential vitamin B3, was observed and characterized using HPLC-UV and gas chromatography/mass spectrometry. This new reaction pathway may present further contribution to our knowledge of Myosmine's significance in human food including its activation in human organism, foodstuffs, and biological systems.
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Abstract 1603: Relevance of Myosmine in cigarette filter butt
Prevention Research, 2012Co-Authors: Wolfgang Zwickenpflug, Christof HöggAbstract:Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Risk assessment of tobacco involves the evaluation of toxicological ingredients and their pathway of uptake in human body. Some relevant and significant aspects regarding the conversion of tobacco constituents to cancer suspect and toxicological important substances during tobacco pyrolysis are known. Albeit some mechanisms as shown in the case of tobacco specific N-nitrosamine (TSNA) formation could have been recovered, the majority of these procedures remain obscure and rare knowledge is available concerning the conversion of tobacco constituents to activated reactive intermediates due to tobacco pyrolysis. The concentrations of nicotine and TSNA are balanced using their metabolic profile or biomarkers in urine, blood and saliva to correlate their realistic uptake. Recently the conversion of nicotine to Myosmine during peroxidation reaction was demonstrated which could be similar to processes during tobacco pyrolysis. In the case of both tobacco alkaloids nicotine and Myosmine problems may arise from classification of their origin. The amount of Myosmine which is formed from nicotine would add to the natural given concentration in tobacco, on the other hand nicotine concentration would be diminished by this conversion. This effect would cause uncertainty of validation and biomarkers of these substances and their derived TSNA in urine, blood and saliva. As reported in the literature the filter analyses of cigarette promises a practicable methodology which would lead to preliminary insights not only in constituents of mainstream smoke (MS), in relation to environmental smoke (ETS), but also about possible candidates up taken in human organism. At the moment the effect under the concern of toxicology is not clear, but the conversion of nicotine to Myosmine may be demonstrated by the analysis of cigarette filter butts from smoked cigarettes. For this reason cigarette butts were collected and the filters separated. The filters were shredded and subjected to the specific extraction procedure. The resulting extract was further cleaned up, enriched by solid-phase-extraction (SPE) procedure and analysed by high performance liquid chromatography - diode array detection (HPLC-DAD), whereupon Myosmine was detected. These preliminary results clearly demonstrate that the investigation of effects from tobacco smoke in biological model systems and human being demands an accurate quantification of its most toxic relevant ingredients including the profile from conversion of nicotine to Myosmine via pyrolysis. Considering the discussion of carcinogenic and toxicological risk assessment of tobacco use, the problems correlating nicotine, Myosmine and TSNA from cigarette smoke requires further declaration. Acknowledgement: This work was supported by DFG grant Zwi59/2-2, and TY 81/1-2 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1603. doi:1538-7445.AM2012-1603
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Abstract 5549: Formation of propylamine during peroxidation of the tobacco alkaloid Myosmine
Carcinogenesis, 2011Co-Authors: Wolfgang Zwickenpflug, Christof HöggAbstract:The alkaloid Myosmine is widespread in the biosphere including food materials and tobacco. Its activation in vitro and in vivo, especially in biological systems, is documented by per-oxidation, CYP 450 systems and N-nitrosation procedure. As reported, activation of tobacco specific N-nitrosamines (TSNA) N’-nitroso-nornicotine (NNN) and 4-(methylnitros-amino)-1-(3-pyridyl)-1-butanone (NNK), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanole (NNAL) leads to hydroxypyridylbutanone (HPB) which is also generated in case of Myosmine by N-nitrosation, peroxidation and in rat experiments. The precursor of HPB is the highly reactive intermediate species POB which is assumed to be responsible for DNA-adducts causing tumorigenesis and cancer. Additionally, during peroxidation procedure from Myosmine and in metabolic studies with rats compound 3-carbinol was detected. Activation via peroxidation of the alkaloid is performed at the C=N pyrrolidine-ring position preferentially leading to unstable oxirane formation. Subsequently decay between 2’-and 3’position takes place yielding 3-carbinol. Further degradation products of the pyrrolidine-oxirane decay were not known till now, but could be high-reactive intermediates. In our investigations we detected the amino propyl-moiety as additional fragment from pyrrolidine oxirane ring decay. Therefore, during Myosmine peroxidation generation of two high-reactive species appear to be plausible. Either 3-picolyl derivative could lead to 3-carbinol and subsequently to nicotinic acid, or other fragment, the propylamino-intermediate reacts to the corresponding amine. Existence of 3-carbinol was reported by Myosmine-peroxidation, but elucidating the postulated new propyl-amino pathway is in focus of our current interest. Myosmine was peroxidated by hydro-genperoxide as reported earlier and the formed propylamine amount could be directly de-rivatized by dansylchloride. The derivatised amine (dansylated propylamine) was analysed with high pressure liquid chromatography (HPLC) instrumentation using fluorescence detection with excitation at 320 nm and emission at 500 nm. Retention times were compared by analysis of reference substances. Possibility of Myosmine activation to high-reactive amine derivatives with peroxides allows conversion of the substance under influence of ROS (reactive oxygen species). This new activation pathway may result in interaction of the propylamino-mojety with proteins, cell-receptors or DNA. A possible carcinogenic risk of Myosmine uptake by humans could not be excluded. Further experiments are demanded to elucidate the new pathway in view of a possible carcinogenic risk of Myosmine. Acknowledgement: This work was supported by DFG grant Zwi59/2-2, and TY 81/1-2 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 5549. doi:10.1158/1538-7445.AM2011-5549
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Abstract 3474: Formation of Myosmine under oxidation of nicotine
Carcinogenesis, 2010Co-Authors: Wolfgang Zwickenpflug, Christof HoeggAbstract:Proceedings: AACR 101st Annual Meeting 2010‐‐ Apr 17‐21, 2010; Washington, DC Nicotine and Myosmine are alkaloids in tobacco products at which nicotine occurs in 200fold higher concentrations than Myosmine. Nicotine is restricted on tobacco mainly, but Myosmine is widespread in the biosphere and food materials additionally. Activation of nicotine showed amongst others N-nitrosation conversion to a compound class, the tobacco specific N-nitrosamines (TSNA). N’-nitrosonornicotine (NNN), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) represent nicotine derived substances. These are assumed to be responsible for tumorigenesis and cancer disease, especially from the lung after activation to highly reactive intermediate species pyridyloxobutanone (POB). POB is known in the context of CYP 450 dependent activation of TSNA and was detected in DNA of tissues from laboratory animals, after TSNA application. The POB-DNA adducts release under hydrolysis 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) which was observed also during Myosmine metabolism in rats, under N-nitrosation and under peroxidation procedures of this compound. Partially, nicotine and Myosmine seem to be metabolized on similar way and support assumption from employment of identical CYP450 isozymes. Oxidation processes of nicotine and Myosmine employing non CYP450 dependent systems undergoe different pathways involving N or N’ ring positions of their pyridine and pyrrole structures. Peroxidation of nicotine is reported under formation of nicotine N-oxides mainly. First results of finding higher Myosmine contents in cigarette filter tips from smoked in relation to unburned cigarettes gave rise to deliberation of possible conversion of nicotine to Myosmine. Following, (−)-nicotine in concentrations equivalent to amount in cigarettes 4.9-5.5µmol was incubated with hydrogen peroxide at 37°C and analyzed. To simulate the assumed reaction on biological systems, (−)-nicotine was incubated with horse radish peroxidase (HRP) and occurence of the relevant compounds analyzed. The assays were directly measured with high pressure liquid chromatography (HPLC) instrumentation and confirmed by cochromatography with respective standard compounds. Our results showed formation of Myosmine under peroxidation from (−)-nicotine. This would mean conversion of nicotine to Myosmine releases activated methyl-species, which could undergo protein or DNA methylation. This possible effect would indicate ability of nicotine to become activated not only as nitrosated but also as peroxidated species. Additional experiments are demanded to elucidate possible carcinogenic risk of nicotine conversion to Myosmine. Acknowledgement: This work was supported by DFG grant 59/2-2 Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3474.
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Evaluation of the mutagenic effects of Myosmine using the HPRT gene mutation assay
Cancer Research, 2008Co-Authors: Joachim Havla, Stefan Tyroller, Wolfgang Zwickenpflug, Elmar Richter, Courtney E. Hill, Sherif Z. Abdel-rahmanAbstract:AACR Annual Meeting-- Apr 12-16, 2008; San Diego, CA 4315 Alkylating mutagens found in tobacco such as tobacco-specific nitrosamines (TSNA) are able to form DNA adducts by methylation and/or pyridyloxobutylation. The tobacco alkaloid Myosmine, which is wide spread in human diets, also gives rise to pyridyloxobutyl DNA adducts. In contrast to TSNA requiring metabolic activation, Myosmine can be easily activated by nitrosation and peroxidation. The resulting adducts can induce DNA damage if not repaired by DNA repair machinery as shown in human lymphocytes, nasal mucosa and human cell lines using the comet assay. The direct reversal DNA repair protein, encoded by the polymorphic O6-Methylguanine-DNA-methyltransferase (MGMT) gene removes these adducts from the DNA. Three coding single nucleotide polymorphisms (cSNPs) in the MGMT gene are believed to affect MGMT function, and these, in turn, could alter the repair of such adducts. Using a modified cloning HPRT gene mutation assay, one of the most widely used somatic cell mutation assays, we determined the mutant frequency in human lymphocytes treated in vitro with Myosmine. These lymphocytes were all MGMT wild-type lymphocytes with none of the three known variants. Dose-response experiments demonstrated a strong antiproliferative effect of 1 and 5 mM Myosmine after 24 h of incubation. After incubation with 1 mM for 4 hours, viability slightly decreased by 3% (p < 0.05) but proliferation and cloning efficiency were not affected. Analysis of 14 samples after exposure to Myosmine (1 mM for 4 hours) resulted in a 56% increase in mutant frequency from 0.73±0.58 x 10-6 in control to 1.14±0.89 x 10-6 in Myosmine-treated lymphocytes (p < 0.05). These preliminary data confirm the mutagenicity of Myosmine to human lymphocytes under the tested experimental conditions. Further studies with MGMT polymorphic lymphocytes conferring impaired repair capacity, and taking into account the dependence of Myosmine activation on pH and nitrosative stress, are warranted.
Rosa Draisci - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography with tandem mass spectrometry method for the determination of nicotine and minor tobacco alkaloids in electronic cigarette refill liquids and second hand generated aerosol
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Marco Famele, Jolanda Palmisani, Carolina Ferranti, Carmelo Abenavoli, L Palleschi, Rosanna Mancinelli, Rosanna Maria Fidente, Gianluigi De Gennaro, Rosa DraisciAbstract:A liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of nicotine and seven minor tobacco alkaloids in both refill liquids for electronic cigarettes and their generated aerosol was developed and validated. The limit of detection and limit of quantification values were 0.3–20.0 and 1.0–31.8 ng/mL, respectively. Within-laboratory reproducibility was 8.2–14.2% at limit of quantification values and 4.8–12.7 % at other concentration levels. Inter-day recovery was 75.8–116.4%. The method was applied to evaluate the compliance of commercial liquids (n = 95) with their labels and to assess levels of minor alkaloids. Levels of nicotine and its correlated compounds were also evaluated in generated aerosol. About 47% of samples showed differences above ± 10 % of the stated nicotine concentration. About 78% of the “zero nicotine” liquids showed traces in the range of 1.3 ± 0.1–254.0 ± 14.6 μg/mL. Nicotine-N'-oxides, Myosmine, and anatabine were the most common minor alkaloids in liquids containing nicotine. Nicotine and N'-oxides were detected in all air samples when aerosol was generated from liquids containing nicotine. Nicotine average emissions from electronic cigarette (2.7 ± 0.9 μg/m3) were significantly lower (p < 0.01, t-Test) respect to conventional cigarette (30.2 ± 1.5 μg/m3). This article is protected by copyright. All rights reserved
Stefan Tyroller - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of the mutagenic effects of Myosmine using the HPRT gene mutation assay
Cancer Research, 2008Co-Authors: Joachim Havla, Stefan Tyroller, Wolfgang Zwickenpflug, Elmar Richter, Courtney E. Hill, Sherif Z. Abdel-rahmanAbstract:AACR Annual Meeting-- Apr 12-16, 2008; San Diego, CA 4315 Alkylating mutagens found in tobacco such as tobacco-specific nitrosamines (TSNA) are able to form DNA adducts by methylation and/or pyridyloxobutylation. The tobacco alkaloid Myosmine, which is wide spread in human diets, also gives rise to pyridyloxobutyl DNA adducts. In contrast to TSNA requiring metabolic activation, Myosmine can be easily activated by nitrosation and peroxidation. The resulting adducts can induce DNA damage if not repaired by DNA repair machinery as shown in human lymphocytes, nasal mucosa and human cell lines using the comet assay. The direct reversal DNA repair protein, encoded by the polymorphic O6-Methylguanine-DNA-methyltransferase (MGMT) gene removes these adducts from the DNA. Three coding single nucleotide polymorphisms (cSNPs) in the MGMT gene are believed to affect MGMT function, and these, in turn, could alter the repair of such adducts. Using a modified cloning HPRT gene mutation assay, one of the most widely used somatic cell mutation assays, we determined the mutant frequency in human lymphocytes treated in vitro with Myosmine. These lymphocytes were all MGMT wild-type lymphocytes with none of the three known variants. Dose-response experiments demonstrated a strong antiproliferative effect of 1 and 5 mM Myosmine after 24 h of incubation. After incubation with 1 mM for 4 hours, viability slightly decreased by 3% (p < 0.05) but proliferation and cloning efficiency were not affected. Analysis of 14 samples after exposure to Myosmine (1 mM for 4 hours) resulted in a 56% increase in mutant frequency from 0.73±0.58 x 10-6 in control to 1.14±0.89 x 10-6 in Myosmine-treated lymphocytes (p < 0.05). These preliminary data confirm the mutagenicity of Myosmine to human lymphocytes under the tested experimental conditions. Further studies with MGMT polymorphic lymphocytes conferring impaired repair capacity, and taking into account the dependence of Myosmine activation on pH and nitrosative stress, are warranted.
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tissue distribution and excretion of Myosmine after i v administration to long evans rats using quantitative whole body autoradiography
Archives of Toxicology, 2007Co-Authors: Susanna Glas, Stefan Tyroller, Wolfgang Zwickenpflug, Kurt Steiner, Gudrun Kiefer, Elmar RichterAbstract:Occurrence of the tobacco alkaloid Myosmine has been proven in various staple foods, vegetables and fruits. Myosmine can be easily activated by nitrosation yielding 4-hydroxy-1-(3-pyridyl)-butanone (HPB) and the esophageal carcinogen N′-nitrosonornicotine. Most of the reaction products after Myosmine peroxidation were also identified as urinary metabolites after oral administration to rats. Whole-body autoradiography with freeze dried or multiple solvent extracted tissue sections was used to trace [2′-14C]Myosmine (0.1 mCi/kg bw) 0.1, 0.25, 1, 4 and 24 h after i.v. injection in Long–Evans rats. In addition, in vitro binding of radioactivity to esophageal and eye tissue was determined and excretion of radioactivity via urine and feces was quantified. Radioactivity is rapidly eliminated by renal excretion. Approximately 30% of the administered radioactivity was recovered in urine within the first 4 h and excretion with urine (72%) and feces (15%) was nearly complete after 24 h. A rapid concentration of radioactivity can be seen in the stomach and in the salivary and lachrymal glands. Rats killed 1 and 4 h after treatment showed by far the highest labeling in the accessory genital gland. High levels of nonextractable radioactivity were present in esophageal tissue and melanin. The half lives for the disappearance of radioactivity from various tissues are in the order of about 1 h. Eye and esophagus sections both showed nonextractable labeling after in vitro incubation with 14C-Myosmine. In conclusion, the toxicological significance of Myosmine accumulation in esophagus and accessory genital gland requires further investigations. Hair analysis might be applicable for Myosmine biomonitoring, because of possible enrichment in melanin containing tissues.
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3 hydroxyMyosmine as specific urinary biomarker for Myosmine exposure development of a method for quantitation
Cancer Research, 2006Co-Authors: Stefan Tyroller, Wolfgang Zwickenpflug, Elmar RichterAbstract:Proc Amer Assoc Cancer Res, Volume 47, 2006 463 Since the widespread occurrence of Myosmine in different foods and in tobacco products has been shown, investigations on possible in vitro or in vivo activation pathways have pointed out that Myosmine can rapidly and completely be converted under nitrosative or under peroxidative conditions. In this context, reactive intermediates are likely formed which may interact with biological material. This is in accordance with DNA damage by Myosmine in cellular systems. Because of its ubiquitous occurrence and its genotoxicity, specific biomarkers of Myosmine uptake are needed. In the course of studies on its in vivo metabolism, 3′-hydroxyMyosmine has been identified as urinary metabolite after oral administration to rats besides 3-pyridylacetic acid, 4-oxo-4-(3-pyridyl)butanoic acid, 3-pyridylmethanol and 4-hydroxy-1-(3-pyridyl)-1-butanone. 3′-HydroxyMyosmine can be assumed to be exclusively formed from Myosmine and might therefore be a promising candidate as urinary biomarker for Myosmine exposure. First, a HPLC-UV/DAD method was developed which turned out to be not specific and sensitive enough. Due to the low amount of 3′-hydroxyMyosmine in rat urine, the limit of detection is very important for an applicable method and therefore GC/MS has been turned out as the most promising alternative. Measurements were executed in the 70 eV electron impact mode without derivatization of the 3′-hydroxyMyosmine. A dilution series of 3′-hydroxyMyosmine dissolved in n-butylacetate ranging from 4.5 ng to 4.5 pg on column was measured monitoring the ions m/z 105 and 162. The limit of detection was 20 pg on column with a signal to noise ratio of at least 5. The response of the mass spectrometer was linear and the obtained areas fitted with r2 0.9952. For quantification of 3′-hydroxyMyosmine an internal standard had to be established. Due to its known behaviour during GC-MS and its proven applicability from studies on Myosmine in foods, D4-Myosmine was used. The ions m/z 122 and 150 were monitored with a linear response between 0.77 ng and 7.7 pg on column. The response factor for D4-Myosmine versus 3′-hydroxyMyosmine was ∼4.5. For extraction of the analyte and the internal standard from urine samples, n-butylacetate and saturated K2CO3 solution were added. An aliquot of the n-butylacetate layer was directly used for GC/MS without further purification. High reproducibility (<5% deviation on consecutive days) and high recoveries for D4-Myosmine (92%) and 3′-hydroxyMyosmine (80%) were obtained. A feasible method for detection and quantification of 3′-hydroxyMyosmine in urine has been developed. Further investigations are needed including animal experiments feeding Myosmine. Finally, occurrence of 3′-hydroxyMyosmine in human urine has to be proven. Supported by a grant from the Institute for Science and Health.
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Reaction of the tobacco alkaloid Myosmine with hydrogen peroxide.
Chemical research in toxicology, 2006Co-Authors: Wolfgang Zwickenpflug, Stefan TyrollerAbstract:Myosmine is not only one of the minor tobacco alkaloids but is also present in various foods. Therefore, research on Myosmine metabolism and activation has been intensified. 3-Pyridylacetic acid, 4-oxo-4-(3-pyridyl)butanoic acid (keto acid), 3-pyridylmethanol, 3‘-hydroxyMyosmine, and 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) have been identified as urinary metabolites after oral administration to female Wistar rats. Although N-nitrosation of Myosmine, yielding N‘-nitrosonornicotine (NNN) and HPB, was considered as a possible in vivo activation route, the formation pathways of most metabolites could not be explained until now. Therefore, under consideration of its high reactivity due to its imine structure, peroxidation of Myosmine seemed to be a promising additional activation pathway. In vitro peroxidation using Myosmine (8.9 μmol in 200 μL methanol) with a mixture of hydrogen peroxide (57.6 μmol, 5 μL of a 35% solution) and acetic acid anhydride (106 μmol, 10 μL) already showed high yields of reaction pr...
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Metabolism of Myosmine in Wistar rats.
Drug metabolism and disposition: the biological fate of chemicals, 2005Co-Authors: Wolfgang Zwickenpflug, Stefan Tyroller, Elmar RichterAbstract:The alkaloid Myosmine is present not only in tobacco products but also in various foods. Myosmine is easily nitrosated, yielding 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB) and the esophageal tobacco carcinogen N'-nitrosonornicotine. Due to its widespread occurrence, investigations on the metabolism and activation of Myosmine are needed for risk assessment. Therefore, the metabolism of Myosmine has been studied in Wistar rats treated with single oral doses of [pyridine-5-3H]Myosmine at 0.001, 0.005, 0.5, and 50 micromol/kg body weight. Oral administration was achieved by feeding a labeled apple bite. Radioactivity was completely recovered in urine and feces within 48 h. At the two lower doses, 0.001 and 0.005 micromol/kg, a higher percentage of the radioactivity was excreted in urine (86.2 +/- 4.9% and 88.9 +/- 1.7%) as compared with the higher doses, 0.5 and 50 micromol/kg, where only 77.8 +/- 7.3% and 75.4 +/- 6.6% of the dose was found in urine. Within 24 h, urinary excretion of radioactivity was nearly complete with less than 4% of the total urinary output appearing between 24 and 48 h. The two major metabolites accounting for >70% of total radioactivity in urine were identified as 3-pyridylacetic acid (20-26%) and 4-oxo-4-(3-pyridyl)butyric acid (keto acid, 50-63%) using UV-diode array detection and gas chromatography-mass spectrometry measurements. 3-Pyridylmethanol (3-5%), 3'-hydroxyMyosmine (2%) and HPB (1-3%) were detected as minor metabolites. 3'-HydroxyMyosmine is exclusively formed from Myosmine and therefore might be used as a urinary biomarker for Myosmine exposure in the future.
Marco Famele - One of the best experts on this subject based on the ideXlab platform.
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liquid chromatography with tandem mass spectrometry method for the determination of nicotine and minor tobacco alkaloids in electronic cigarette refill liquids and second hand generated aerosol
IEEE Journal of Solid-state Circuits, 2017Co-Authors: Marco Famele, Jolanda Palmisani, Carolina Ferranti, Carmelo Abenavoli, L Palleschi, Rosanna Mancinelli, Rosanna Maria Fidente, Gianluigi De Gennaro, Rosa DraisciAbstract:A liquid chromatography with tandem mass spectrometry method for the simultaneous quantification of nicotine and seven minor tobacco alkaloids in both refill liquids for electronic cigarettes and their generated aerosol was developed and validated. The limit of detection and limit of quantification values were 0.3–20.0 and 1.0–31.8 ng/mL, respectively. Within-laboratory reproducibility was 8.2–14.2% at limit of quantification values and 4.8–12.7 % at other concentration levels. Inter-day recovery was 75.8–116.4%. The method was applied to evaluate the compliance of commercial liquids (n = 95) with their labels and to assess levels of minor alkaloids. Levels of nicotine and its correlated compounds were also evaluated in generated aerosol. About 47% of samples showed differences above ± 10 % of the stated nicotine concentration. About 78% of the “zero nicotine” liquids showed traces in the range of 1.3 ± 0.1–254.0 ± 14.6 μg/mL. Nicotine-N'-oxides, Myosmine, and anatabine were the most common minor alkaloids in liquids containing nicotine. Nicotine and N'-oxides were detected in all air samples when aerosol was generated from liquids containing nicotine. Nicotine average emissions from electronic cigarette (2.7 ± 0.9 μg/m3) were significantly lower (p < 0.01, t-Test) respect to conventional cigarette (30.2 ± 1.5 μg/m3). This article is protected by copyright. All rights reserved
