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Glatt H, Weißenberg SY, Ehlers A, Lampen A, Seidel A, Schumacher F, Engst W, Meinl W. Formation of DNA Adducts by 1-Methoxy-3-indolylmethylalcohol, a Breakdown Product of a Glucosinolate, in the Mouse: Impact of the SULT1A1 Status-Wild-Type, Knockout or Humanised. Int J Mol Sci 2024; 25:3824. [PMID: 38612635 PMCID: PMC11012018 DOI: 10.3390/ijms25073824] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 03/20/2024] [Accepted: 03/22/2024] [Indexed: 04/14/2024] Open
Abstract
We previously found that feeding rats with broccoli or cauliflower leads to the formation of characteristic DNA adducts in the liver, intestine and various other tissues. We identified the critical substances in the plants as 1-methoxy-3-indolylmethyl (1-MIM) glucosinolate and its degradation product 1-MIM-OH. DNA adduct formation and the mutagenicity of 1-MIM-OH in cell models were drastically enhanced when human sulfotransferase (SULT) 1A1 was expressed. The aim of this study was to clarify the role of SULT1A1 in DNA adduct formation by 1-MIM-OH in mouse tissues in vivo. Furthermore, we compared the endogenous mouse Sult1a1 and transgenic human SULT1A1 in the activation of 1-MIM-OH using genetically modified mouse strains. We orally treated male wild-type (wt) and Sult1a1-knockout (ko) mice, as well as corresponding lines carrying the human SULT1A1-SULT1A2 gene cluster (tg and ko-tg), with 1-MIM-OH. N2-(1-MIM)-dG and N6-(1-MIM)-dA adducts in DNA were analysed using isotope-dilution UPLC-MS/MS. In the liver, caecum and colon adducts were abundant in mice expressing mouse and/or human SULT1A1, but were drastically reduced in ko mice (1.2-10.6% of wt). In the kidney and small intestine, adduct levels were high in mice carrying human SULT1A1-SULT1A2 genes, but low in wt and ko mice (1.8-6.3% of tg-ko). In bone marrow, adduct levels were very low, independently of the SULT1A1 status. In the stomach, they were high in all four lines. Thus, adduct formation was primarily controlled by SULT1A1 in five out of seven tissues studied, with a strong impact of differences in the tissue distribution of mouse and human SULT1A1. The behaviour of 1-MIM-OH in these models (levels and tissue distribution of DNA adducts; impact of SULTs) was similar to that of methyleugenol, classified as "probably carcinogenic to humans". Thus, there is a need to test 1-MIM-OH for carcinogenicity in animal models and to study its adduct formation in humans consuming brassicaceous foodstuff.
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Affiliation(s)
- Hansruedi Glatt
- Department Food Safety, Federal Institute of Risk Assessment (BfR), Max-Dohrn-Strasse 8–10, 10589 Berlin, Germany; (S.Y.W.); (A.E.); (A.L.)
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114–116, 14558 Nuthetal, Germany; (F.S.); (W.E.); (W.M.)
| | - Sarah Yasmin Weißenberg
- Department Food Safety, Federal Institute of Risk Assessment (BfR), Max-Dohrn-Strasse 8–10, 10589 Berlin, Germany; (S.Y.W.); (A.E.); (A.L.)
| | - Anke Ehlers
- Department Food Safety, Federal Institute of Risk Assessment (BfR), Max-Dohrn-Strasse 8–10, 10589 Berlin, Germany; (S.Y.W.); (A.E.); (A.L.)
| | - Alfonso Lampen
- Department Food Safety, Federal Institute of Risk Assessment (BfR), Max-Dohrn-Strasse 8–10, 10589 Berlin, Germany; (S.Y.W.); (A.E.); (A.L.)
| | - Albrecht Seidel
- Biochemical Institute for Environmental Carcinogens (BIU), Prof. Dr. Gernot Grimmer-Foundation, Lurup 4, 22927 Grosshansdorf, Germany;
| | - Fabian Schumacher
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114–116, 14558 Nuthetal, Germany; (F.S.); (W.E.); (W.M.)
- Institute of Pharmacy, Freie Universität Berlin, Königin-Luise-Strasse 2–4, 14195 Berlin, Germany
| | - Wolfram Engst
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114–116, 14558 Nuthetal, Germany; (F.S.); (W.E.); (W.M.)
| | - Walter Meinl
- Department of Nutritional Toxicology, German Institute of Human Nutrition (DIfE), Potsdam-Rehbrücke, Arthur-Scheunert-Allee 114–116, 14558 Nuthetal, Germany; (F.S.); (W.E.); (W.M.)
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Nieschalke K, Bergau N, Jessel S, Seidel A, Baldermann S, Schreiner M, Abraham K, Lampen A, Monien BH, Kleuser B, Glatt H, Schumacher F. Urinary Excretion of Mercapturic Acids of the Rodent Carcinogen Methyleugenol after a Single Meal of Basil Pesto: A Controlled Exposure Study in Humans. Chem Res Toxicol 2023; 36:1753-1767. [PMID: 37875262 PMCID: PMC10664145 DOI: 10.1021/acs.chemrestox.3c00212] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2023] [Indexed: 10/26/2023]
Abstract
Methyleugenol (ME), found in numerous plants and spices, is a rodent carcinogen and is classified as "possibly carcinogenic to humans". The hypothesis of a carcinogenic risk for humans is supported by the observation of ME-derived DNA adducts in almost all human liver and lung samples examined. Therefore, a risk assessment of ME is needed. Unfortunately, biomarkers of exposure for epidemiological studies are not yet available. We hereby present the first detection of N-acetyl-l-cysteine conjugates (mercapturic acids) of ME in human urine samples after consumption of a popular ME-containing meal, pasta with basil pesto. We synthesized mercapturic acid conjugates of ME, identified the major product as N-acetyl-S-[3'-(3,4-dimethoxyphenyl)allyl]-l-cysteine (E-3'-MEMA), and developed methods for its extraction and LC-MS/MS quantification in human urine. For conducting an exposure study in humans, a basil cultivar with a suitable ME content was grown for the preparation of basil pesto. A defined meal containing 100 g of basil pesto, corresponding to 1.7 mg ME, was served to 12 participants, who collected the complete urine at defined time intervals for 48 h. Using d6-E-3'-MEMA as an internal standard for LC-MS/MS quantification, we were able to detect E-3'-MEMA in urine samples of all participants collected after the ME-containing meal. Excretion was maximal between 2 and 6 h after the meal and was completed within about 12 h (concentrations below the limit of detection). Excreted amounts were only between 1 and 85 ppm of the ME intake, indicating that the ultimate genotoxicant, 1'-sulfooxy-ME, is formed to a subordinate extent or is not efficiently detoxified by glutathione conjugation and subsequent conversion to mercapturic acids. Both explanations may apply cumulatively, with the ubiquitous detection of ME DNA adducts in human lung and liver specimens arguing against an extremely low formation of 1'-sulfooxy-ME. Taken together, we hereby present the first noninvasive human biomarker reflecting an internal exposure toward reactive ME species.
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Affiliation(s)
- Kai Nieschalke
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Nick Bergau
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Sönke Jessel
- Biochemical
Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation, 22927 Grosshansdorf, Germany
| | - Albrecht Seidel
- Biochemical
Institute for Environmental Carcinogens, Prof. Dr. Gernot Grimmer-Foundation, 22927 Grosshansdorf, Germany
| | - Susanne Baldermann
- Department
Plant Quality and Food Security, Leibniz
Institute of Vegetable and Ornamental Crops (IGZ), 14979 Grossbeeren, Germany
- Faculty of
Life Sciences: Food, Nutrition & Health, University of Bayreuth, 95326 Kulmbach, Germany
| | - Monika Schreiner
- Department
Plant Quality and Food Security, Leibniz
Institute of Vegetable and Ornamental Crops (IGZ), 14979 Grossbeeren, Germany
| | - Klaus Abraham
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Alfonso Lampen
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Bernhard H. Monien
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Burkhard Kleuser
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
| | - Hansruedi Glatt
- Department
of Food Safety, German Federal Institute
for Risk Assessment (BfR), 10589 Berlin, Germany
| | - Fabian Schumacher
- Department
of Nutritional Toxicology, Institute of Nutritional Science, University of Potsdam, 14558 Nuthetal, Germany
- Department
of Pharmacology and Toxicology, Institute of Pharmacy, Freie Universität Berlin, 14195 Berlin, Germany
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Davidsen JM, Cohen SM, Eisenbrand G, Fukushima S, Gooderham NJ, Guengerich FP, Hecht SS, Rietjens IMCM, Rosol TJ, Harman CL, Taylor SV. FEMA GRAS assessment of derivatives of basil, nutmeg, parsley, tarragon and related allylalkoxybenzene-containing natural flavor complexes. Food Chem Toxicol 2023; 175:113646. [PMID: 36804339 DOI: 10.1016/j.fct.2023.113646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/26/2023] [Accepted: 01/30/2023] [Indexed: 02/18/2023]
Abstract
In 2015, the Expert Panel of the Flavor and Extract Manufacturers Association (FEMA) initiated a program for the re-evaluation of the safety of over 250 natural flavor complexes (NFCs) used as flavoring ingredients in food. In this publication, tenth in the series, NFCs containing a high percentage of at least one naturally occurring allylalkoxybenzene constituent with a suspected concern for genotoxicity and/or carcinogenicity are evaluated. In a related paper, ninth in the series, NFCs containing anethole and/or eugenol and relatively low percentages of these allylalkoxybenzenes are evaluated. The Panel applies the threshold of toxicological concern (TTC) concept and evaluates relevant toxicology data on the NFCs and their respective constituent congeneric groups. For NFCs containing allylalkoxybenzene constituent(s), the estimated intake of the constituent is compared to the TTC for compounds with structural alerts for genotoxicity and when exceeded, a margin of exposure (MOE) is calculated. BMDL10 values are derived from benchmark dose analyses using Bayesian model averaging for safrole, estragole and methyl eugenol using EPA's BMDS software version 3.2. BMDL10 values for myristicin, elemicin and parsley apiole were estimated by read-across using relative potency factors. Margins of safety for each constituent congeneric group and MOEs for each allylalkoxybenzene constituent for each NFC were determined that indicate no safety concern. The scope of the safety evaluation contained herein does not include added use in dietary supplements or any products other than food. Ten NFCs, derived from basil, estragon (tarragon), mace, nutmeg, parsley and Canadian snakeroot were determined or affirmed as generally recognized as safe (GRAS) under their conditions of intended use as flavor ingredients based on an evaluation of each NFC and the constituents and congeneric groups therein.
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Affiliation(s)
- Jeanne M Davidsen
- Flavor and Extract Manufacturers Association, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA
| | - Samuel M Cohen
- Havlik-Wall Professor of Oncology, Dept. of Pathology and Microbiology, University of Nebraska Medical Center, 983135 Nebraska Medical Center, Omaha, NE, 68198-3135, USA
| | - Gerhard Eisenbrand
- University of Kaiserslautern, Germany (Retired), Kühler Grund 48/1, 69126, Heidelberg, Germany
| | - Shoji Fukushima
- Japan Bioassay Research Center, 2445 Hirasawa, Hadano, Kanagawa, 257-0015, Japan
| | - Nigel J Gooderham
- Dept. of Metabolism, Digestion, Reproduction, Imperial College London, Sir Alexander Fleming Building, London, SW7 2AZ, United Kingdom
| | - F Peter Guengerich
- Dept. of Biochemistry, Vanderbilt University School of Medicine, Nashville, TN, 37232-0146, USA
| | - Stephen S Hecht
- Masonic Cancer Center and Dept. of Laboratory Medicine and Pathology, Cancer and Cardiovascular Research Building, 2231 6th St, S.E, Minneapolis, MN, 55455, USA
| | - Ivonne M C M Rietjens
- Division of Toxicology, Wageningen University, Stippeneng 6708 WE, Wageningen, the Netherlands
| | - Thomas J Rosol
- Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, 1 Ohio University, Athens, OH, 45701, USA
| | - Christie L Harman
- Flavor and Extract Manufacturers Association, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA
| | - Sean V Taylor
- Scientific Secretary to the FEMA Expert Panel, 1101 17th Street, N.W., Suite 700, Washington, D.C, 20036, USA.
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Götz ME, Sachse B, Schäfer B, Eisenreich A. Myristicin and Elemicin: Potentially Toxic Alkenylbenzenes in Food. Foods 2022; 11:1988. [PMID: 35804802 PMCID: PMC9265716 DOI: 10.3390/foods11131988] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/22/2022] [Accepted: 07/01/2022] [Indexed: 11/17/2022] Open
Abstract
Alkenylbenzenes represent a group of naturally occurring substances that are synthesized as secondary metabolites in various plants, including nutmeg and basil. Many of the alkenylbenzene-containing plants are common spice plants and preparations thereof are used for flavoring purposes. However, many alkenylbenzenes are known toxicants. For example, safrole and methyleugenol were classified as genotoxic carcinogens based on extensive toxicological evidence. In contrast, reliable toxicological data, in particular regarding genotoxicity, carcinogenicity, and reproductive toxicity is missing for several other structurally closely related alkenylbenzenes, such as myristicin and elemicin. Moreover, existing data on the occurrence of these substances in various foods suffer from several limitations. Together, the existing data gaps regarding exposure and toxicity cause difficulty in evaluating health risks for humans. This review gives an overview on available occurrence data of myristicin, elemicin, and other selected alkenylbenzenes in certain foods. Moreover, the current knowledge on the toxicity of myristicin and elemicin in comparison to their structurally related and well-characterized derivatives safrole and methyleugenol, especially with respect to their genotoxic and carcinogenic potential, is discussed. Finally, this article focuses on existing data gaps regarding exposure and toxicity currently impeding the evaluation of adverse health effects potentially caused by myristicin and elemicin.
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Affiliation(s)
| | | | | | - Andreas Eisenreich
- Department of Food Safety, German Federal Institute for Risk Assessment (BfR), Max-Dohrn-Str. 8-10, 10589 Berlin, Germany; (M.E.G.); (B.S.); (B.S.)
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Ahsan T, Shoily SS, Fatema K, Sajib AA. Impacts of 119 missense variants at functionally important sites of drug-metabolizing human cytosolic sulfotransferase SULT1A1: An in silico study. INFORMATICS IN MEDICINE UNLOCKED 2022. [DOI: 10.1016/j.imu.2021.100836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Alkenylbenzenes in Foods: Aspects Impeding the Evaluation of Adverse Health Effects. Foods 2021; 10:foods10092139. [PMID: 34574258 PMCID: PMC8469824 DOI: 10.3390/foods10092139] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Revised: 09/03/2021] [Accepted: 09/07/2021] [Indexed: 12/15/2022] Open
Abstract
Alkenylbenzenes are naturally occurring secondary plant metabolites, primarily present in different herbs and spices, such as basil or fennel seeds. Thus, alkenylbenzenes, such as safrole, methyleugenol, and estragole, can be found in different foods, whenever these herbs and spices (or extracts thereof) are used for food production. In particular, essential oils or other food products derived from the aforementioned herbs and spices, such as basil-containing pesto or plant food supplements, are often characterized by a high content of alkenylbenzenes. While safrole or methyleugenol are known to be genotoxic and carcinogenic, the toxicological relevance of other alkenylbenzenes (e.g., apiol) regarding human health remains widely unclear. In this review, we will briefly summarize and discuss the current knowledge and the uncertainties impeding a conclusive evaluation of adverse effects to human health possibly resulting from consumption of foods containing alkenylbenzenes, especially focusing on the genotoxic compounds, safrole, methyleugenol, and estragole.
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Yang X, Feng Y, Zhang Z, Wang H, Li W, Wang DO, Peng Y, Zheng J. In Vitro and In Vivo Evidence for RNA Adduction Resulting from Metabolic Activation of Methyleugenol. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:15134-15141. [PMID: 33296206 DOI: 10.1021/acs.jafc.0c04880] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Methyleugenol (ME) is a ubiquitous component in spices and other culinary herbal products. A prevailing theory in ME toxicity is its ability to be metabolically activated by P450 enzymes and sulfotransferases, which initiates sequential reactions of the resulting metabolites with functional biomolecules. The present study aimed at a potential interaction between the reactive metabolites of ME and RNA. Cultured mouse primary hepatocytes were incubated with ME followed by RNA extraction and NaOH and alkaline phosphatase-based RNA hydrolysis. Three adenosine adducts were detected in the hydrolytic mixture by LC-MS/MS. The same adenosine adducts were also detected in hepatic tissues harvested from ME-treated mice. These three adducts were chemically synthesized and structurally characterized by 1H NMR. Additionally, two guanosine adducts and one cytidine adduct were detected in the in vivo samples. These results provided solid evidence that the reactive metabolites of ME attacked RNA, resulting in RNA adduction.
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Affiliation(s)
- Xiaojing Yang
- State Key Laboratory of Functions and Applications of Medicinal Plants, Key Laboratory of Pharmaceutics of Guizhou Province, Guizhou Medical University, Guiyang, Guizhou 550004, P. R. China
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Yukun Feng
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
- Institute of Shandong Xinhua Pharmaceutical Co., Ltd., Zibo 255000, China
| | - Zhengyu Zhang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Hui Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Weiwei Li
- State Key Laboratory of Functions and Applications of Medicinal Plants, Key Laboratory of Pharmaceutics of Guizhou Province, Guizhou Medical University, Guiyang, Guizhou 550004, P. R. China
| | - Dan Ohtan Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
- Institute for Integrated Cell-Material Sciences (iCeMS), Kyoto University, Kyoto 606-8501, Japan
| | - Ying Peng
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
| | - Jiang Zheng
- State Key Laboratory of Functions and Applications of Medicinal Plants, Key Laboratory of Pharmaceutics of Guizhou Province, Guizhou Medical University, Guiyang, Guizhou 550004, P. R. China
- Key Laboratory of Environmental Pollution Monitoring and Disease Control, Ministry of Education, Guizhou Medical University, Guiyang 550025, P. R. China
- Wuya College of Innovation, Shenyang Pharmaceutical University, Shenyang 110016, China
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Feng Y, Wang S, Wang H, Peng Y, Zheng J. Urinary Methyleugenol-deoxyadenosine Adduct as a Potential Biomarker of Methyleugenol Exposure in Rats. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:1258-1263. [PMID: 29328669 DOI: 10.1021/acs.jafc.7b05186] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Methyleugenol (ME), a natural ingredient of several herbs and spices used in the human diet, is hepatocarcinogenic in rodents. Following metabolic activation to the reactive carbocation intermediate, ME can bind covalently to DNA, which is directly associated with its carcinogenicity. In this work, a non-invasive approach to determine ME exposure was established by monitoring the urinary N6-(methylisoeugenol-3'-yl)-2'-deoxyadenosine (ME-dA) adduct. The developed method entails liquid-liquid extraction enrichment of urinary ME-dA, incorporation of deuterated ME-dA as an internal standard, and analysis by liquid chromatography coupled tandem mass spectrometry. Male rats (10-12 weeks, 180-200 g) were treated (p.o.) with ME, and ME-dA was excreted in urine in a dose- and time-dependent manner. The non-invasive approach enabled us to successfully determine exposure to ME-containing herbs and spices. These results suggest that ME-dA can potentially serve as an effective biomarker of ME exposure in rats. It is expected that the developed approach of detecting urinary ME-dA will facilitate the investigation of ME carcinogenesis.
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Affiliation(s)
- Yukun Feng
- Wuya College of Innovation, Shenyang Pharmaceutical University , Shenyang, Liaoning 110016, People's Republic of China
| | - Saide Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University , Shenyang, Liaoning 110016, People's Republic of China
| | - Hui Wang
- Wuya College of Innovation, Shenyang Pharmaceutical University , Shenyang, Liaoning 110016, People's Republic of China
| | - Ying Peng
- Wuya College of Innovation, Shenyang Pharmaceutical University , Shenyang, Liaoning 110016, People's Republic of China
| | - Jiang Zheng
- Wuya College of Innovation, Shenyang Pharmaceutical University , Shenyang, Liaoning 110016, People's Republic of China
- State Key Laboratory of Functions and Applications of Medicinal Plants, Key Laboratory of Pharmaceutics of Guizhou Province and Guizhou Medical University , Guiyang, Guizhou 550004, People's Republic of China
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Methyleugenol DNA adducts in human liver are associated with SULT1A1 copy number variations and expression levels. Arch Toxicol 2017; 91:3329-3339. [PMID: 28326452 DOI: 10.1007/s00204-017-1955-4] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 03/09/2017] [Indexed: 10/19/2022]
Abstract
Methyleugenol is a rodent hepatocarcinogen occurring in many herbs and spices as well as essential oils used for flavoring. Following metabolic activation by cytochromes P450 (CYPs) and sulfotransferases (SULTs), methyleugenol can form DNA adducts. Previously, we showed that DNA adduct formation by methyleugenol in mouse liver is dependent on SULT1A1 expression and that methyleugenol DNA adducts are abundant in human liver specimens. In humans, SULT1A1 activity is affected by genetic polymorphisms, including single-nucleotide polymorphisms (SNPs) and copy number variations (CNVs). Here we investigated the relationship between individual methyleugenol DNA adduct levels and SULT1A1 in human liver samples. Using isotope-dilution ultraperformance liquid chromatography coupled with tandem mass spectrometry, we quantified methyleugenol DNA adducts in 121 human surgical liver samples. Frequent CNVs, including deletions (f = 3.3%) and duplications (f = 36.4%) of SULT1A1, were identified using qPCR and TaqMan assays in the donors' genomic DNA. SULT1A1 mRNA and protein levels were quantified using microarray data and Western blot analysis, respectively. Methyleugenol DNA adducts were detected in all 121 liver samples studied. Their levels varied 122-fold between individuals and were significantly correlated to both mRNA and protein levels of SULT1A1 (r s = 0.43, and r s = 0.44, respectively). Univariate and multivariate statistical analysis identified significant associations of SULT1A1 CNVs with mRNA (p = 1.7 × 10-06) and protein (p = 4.4 × 10- 10) levels as well as methyleugenol DNA adduct levels (p = 0.003). These data establish the importance of SULT1A1 genotype for hepatic methyleugenol DNA adducts in humans, and they confirm a strong impact of SULT1A1 CNVs on SULT1A1 hepatic phenotype.
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