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Nguyen HD, Vu GH, Hoang LT, Kim MS. Elucidation of toxic effects of 1,2-diacetylbenzene: an in silico study. Forensic Toxicol 2024:10.1007/s11419-024-00702-3. [PMID: 39298088 DOI: 10.1007/s11419-024-00702-3] [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: 01/04/2024] [Accepted: 05/30/2024] [Indexed: 09/21/2024]
Abstract
PURPOSE We aimed to explore the metabolite products of 1,2-diacetylbenzene (DAB) and investigate their harmful effects, physicochemical properties, and biological activities, along with those of DAB itself. METHODS Key approaches included MetaTox, PASS online, ADMESWISS, ADMETlab 2.0, molecular docking, and molecular dynamic simulation to identify metabolites, toxic effects, Lipinski's rule criteria, absorption, distribution, metabolism, and excretion properties, interactions with cytochrome (CYP) 450 isoforms, and the stability of the DAB-cytochrome complex. RESULTS A total of 13 metabolite products from DAB were identified, involving Phase I reactions (aliphatic hydroxylation, epoxidation, oxidative dehydrogenation, and hydrogenation) and Phase II reactions (oxidative sulfation and methylation). Molecular dynamics and modeling revealed a stable interaction between CYP1A2 and DAB, suggesting the involvement of CYP1A2 in DAB metabolism. All studied compounds adhered to Lipinski's rule, indicating their potential as inducers or activators of toxic mechanisms. The physicochemical parameters and pharmacokinetics of the investigated compounds were consistent with their harmful effects, which included neurotoxic, nephrotoxic, endocrine disruptor, and hepatotoxic consequences due to their high gastrointestinal absorption and ability to cross the blood-brain barrier. Various CYP450 isoforms exhibited different functions, and the compounds were found to act as superoxide dismutase inhibitors, neuropeptide Y2 antagonists, glutaminase inhibitors, and activators of caspases 3 and 8. DAB and its metabolites were also associated with apoptosis, oxidative stress, and neuroendocrine disruption. CONCLUSION The toxic effects of DAB and its metabolites were predicted in this study. Further research is warranted to explore their effects on other organs, such as the liver and kidneys, and to validate our findings.
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Affiliation(s)
- Hai Duc Nguyen
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 57922, Republic of Korea.
- Division of Microbiology, Tulane National Primate Research Center, Tulane University, Covington, LA, 70433, USA.
| | - Giang Huong Vu
- Department of Public Heath, Hong Bang Health Center, Hai Phong, Vietnam
| | - Linh Thuy Hoang
- College of Pharmacy, California Northstate University College of Pharmacy, Elk Grove, CA, USA
| | - Min-Sun Kim
- Department of Pharmacy, College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, 57922, Republic of Korea.
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2
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Gao Y, Hu X, Deng C, Wang M, Niu X, Luo N, Ji Y, Li G, An T. New insight into molecular mechanism of P450-Catalyzed metabolism of emerging contaminants and its consequence for human health: A case study of preservative methylparaben. ENVIRONMENT INTERNATIONAL 2023; 174:107890. [PMID: 37001212 DOI: 10.1016/j.envint.2023.107890] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Revised: 03/13/2023] [Accepted: 03/15/2023] [Indexed: 06/19/2023]
Abstract
Hydroxylated metabolites in the living body are considered as a potential biomarker of exposure to emerging contaminations (ECs) and breast cancer, but their formation mechanism has not received enough attention. Besides, the adverse impacts of metabolites during the metabolic transformation of ECs largely remain unknown. In this study, we employed a density functional calculation combing with in-vitro incubation of human liver microsomes to explore the bio-transformation of preservative methylparaben (MPB) in human bodies. Our results showed that hydroxylated metabolites of MPB (OH-MPB) were observed experimentally, while a formation mechanism was revealed at the molecular level. That is, hydroxylated metabolite was exclusively formed via the hydrogen abstraction from the phenolic hydroxyl group of MPB followed by the OH-rebound pathway, rather than the direct hydroxylation on the benzene ring. The increasing of hydroxyl groups on ECs could improve the metabolisms. This was confirmed in the metabolism of ECs without hydroxyl group and with multiple-hydroxyl groups, respectively. Furthermore, toxicity assessments show that compared to parent MPB, the hydroxylated metabolites have increased negative impacts on the gastrointestinal system and liver. A semiquinone product exhibits potential damage in the cardiovascular system and epoxides are toxic to the blood and gastrointestinal system. The findings deepen our insight into the biotransformation of parabens in human health, especially by providing health warnings about the potential impacts caused by semiquinone and epoxides.
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Affiliation(s)
- Yanpeng Gao
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xinyi Hu
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Chuyue Deng
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Mei Wang
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Xiaolin Niu
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Na Luo
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Yuemeng Ji
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China.
| | - Guiying Li
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
| | - Taicheng An
- Guangdong-Hong Kong-Macao Joint Laboratory for Contaminants Exposure and Health, Guangdong Key Laboratory of Environmental Catalysis and Health Risk Control, Institute of Environmental Health and Pollution Control, Guangdong University of Technology, Guangzhou 510006, China; Guangzhou Key Laboratory of Environmental Catalysis and Pollution Control, Key Laboratory of City Cluster Environmental Safety and Green Development of the Ministry of Education, School of Environmental Science and Engineering, Guangdong University of Technology, Guangzhou 510006, China
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3
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Chen H, Zhou A, Sun D, Zhao Y, Wang Y. Theoretical Investigation on the Elusive Reaction Mechanism of Spirooxindole Formation Mediated by Cytochrome P450s: A Nascent Feasible Charge-Shift C-O Bond Makes a Difference. J Phys Chem B 2021; 125:8419-8430. [PMID: 34313131 DOI: 10.1021/acs.jpcb.1c04088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Spirooxindoles are pivotal biofunctional groups widely distributed in natural products and clinic drugs. However, construction of such subtle chiral skeletons is a long-standing challenge to both organic and bioengineering scientists. The knowledge of enzymatic spirooxindole formation in nature may inspire rational design of new catalysts. To this end, we presented a theoretical investigation on the elusive mechanism of the spiro-ring formation at the 3-position of oxindole mediated by cytochrome P450 enzymes (P450). Our calculated results demonstrated that the electrophilic attack of CpdI, the active species of P450, to the substrate, shows regioselectivity, i.e., the attack at the C9 position forms a tetrahedral intermediate involving an unusual feasible charge-shift C9δ+-Oδ- bond, while the attack at the C1 position forms an epoxide intermediate. The predominant route is the first route with the charge-shift bonding intermediate due to holding a relatively lower barrier by >5 kcal mol-1 than the epoxide route, which fits the experimental observations. Such a delocalized charge-shift bond facilitates the formation of a spiro-ring mainly through elongation of the C1-C9 bond to eliminate the aromatization of the tricyclic beta-carboline. Our theoretical results shed profound mechanistic insights for the first time into the elusive spirooxindole formation mediated by P450s.
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Affiliation(s)
- Huanhuan Chen
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Anran Zhou
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Yufen Zhao
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Yong Wang
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China.,Qian Xuesen Collaborative Research Center of Astrochemistry and Space Life Sciences, Ningbo University, Ningbo 315211, Zhejiang, China
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4
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Kamel EM, Lamsabhi AM. The quasi-irreversible inactivation of cytochrome P450 enzymes by paroxetine: a computational approach. Org Biomol Chem 2021; 18:3334-3345. [PMID: 32301459 DOI: 10.1039/d0ob00529k] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The mechanism-based inactivation (MBI) of P450 by paroxetine was investigated by computational analysis. The drug-enzyme interactions were figured out through studying energy profiles of three competing mechanisms. The potency of paroxetine as P450's inhibitor was estimated based on the availability of two active sites for the MBI in the paroxetine structure. The inactivation by the amino site of paroxetine mainly proceeds via the hydrogen atom transfer pathway because of the lower energy demand of its rate determining step. In addition, the low-spin state is the predominant route in the MBI at the methylenedioxo active site as a result of being rebound barrier-free mechanism. Our comparative investigation showed that inactivation at the secondary amine is thermodynamically more favorable because of the lower energy barrier of the dehydration mechanism of the hydroxylated paroxetine complex than its methylenedioxo counterpart. The results of docking analysis coincided with the outputs of DFT calculations since the docking pose with the lowest binding affinity is that for conformation with polar interaction between the amino group of paroxetine and the oxo moiety of P450's active site. Assessment of the molecular dynamics simulations trajectories revealed the favorable interaction of paroxetine with P450.
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Affiliation(s)
- Emadeldin M Kamel
- Chemistry Department, Faculty of Science, Beni-Suef University, Beni-Suef, 62514, Egypt. and Departamento de Química, Universidad Autónoma de Madrid, Módulo 13, Campus de Excelencia UAM-CSIC Cantoblanco, Madrid, Spain
| | - Al Mokhtar Lamsabhi
- Departamento de Química, Universidad Autónoma de Madrid, Módulo 13, Campus de Excelencia UAM-CSIC Cantoblanco, Madrid, Spain and Institute for Advanced Research in Chemical Sciences (IAdChem), Universidad Autónoma de Madrid, 28049 Madrid, Spain
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5
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Jaladanki CK, Gahlawat A, Rathod G, Sandhu H, Jahan K, Bharatam PV. Mechanistic studies on the drug metabolism and toxicity originating from cytochromes P450. Drug Metab Rev 2020; 52:366-394. [DOI: 10.1080/03602532.2020.1765792] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Chaitanya K. Jaladanki
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
| | - Anuj Gahlawat
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
| | - Gajanan Rathod
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
| | - Hardeep Sandhu
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
| | - Kousar Jahan
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
| | - Prasad V. Bharatam
- Department of Medicinal Chemistry and Department of Pharmacoinformatics, National Institute of Pharmaceutical Education and Research (NIPER), SAS Nagar, Punjab, India
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6
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Nolte TM, Chen G, van Schayk CS, Pinto-Gil K, Hendriks AJ, Peijnenburg WJGM, Ragas AMJ. Disentanglement of the chemical, physical, and biological processes aids the development of quantitative structure-biodegradation relationships for aerobic wastewater treatment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 708:133863. [PMID: 31771845 DOI: 10.1016/j.scitotenv.2019.133863] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2019] [Revised: 07/16/2019] [Accepted: 08/08/2019] [Indexed: 04/15/2023]
Abstract
Attenuation of organic compounds in sewage treatment plants (STPs) is affected by a complex interplay between chemical (e.g. ionization, hydrolysis), physical (e.g. sorption, volatilization), and biological (e.g. biodegradation, microbial acclimation) processes. These effects should be accounted for individually, in order to develop predictive cheminformatics tools for STPs. Using measured data from 70 STPs in the Netherlands for 69 chemicals (pharmaceuticals, herbicides, etc.), we highlighted the influences of 1) chemical ionization, 2) sorption to sludge, and 3) acclimation of the microbial consortia on the primary removal of chemicals. We used semi-empirical corrections for each of these influences to deduce biodegradation rate constants upon which quantitative structure-biodegradation relationships (QSBRs) were developed. As shown by a global QSBR, biodegradation in STPs generally relates to structural complexity, size, energetics, and charge distribution. Statistics of the global QSBR were reasonable, being R2training=0.69 (training set of 51 compounds) and R2validation=0.50 (validation set of 18 compounds). Class-specific QSBRs utilized electronic properties potentially relating to rate-limiting enzymatic steps. For class-specific QSBRs, values of R2 of in between 0.7 and 0.8 were obtained. With caution, environmental risk assessment methodologies may apply these models to estimate biodegradation rates for 'data-poor' compounds. The approach also highlights 'meta data' on STP operational parameters needed to develop QSBRs of better predictability in the future.
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Affiliation(s)
- Tom M Nolte
- Department of Environmental Science, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands; Eidgenossische Technische Hochschule (ETH) Zurich, Laboratory of Inorganic Chemistry, Vladimir-Prelog-Weg 1, 8093 Zurich, Switzerland.
| | - Guangchao Chen
- Department of Environmental Science, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands; Institute of Environmental Sciences, Leiden University, 2300 RA Leiden, the Netherlands
| | - Coen S van Schayk
- Department of Environmental Science, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands
| | - Kevin Pinto-Gil
- Research Programme on Biomedical Informatics (GRIB), Institut Hospital del Mar d'Investigacions Mèdiques (IMIM), Dept. of Experimental and Health Sciences, Universitat Pompeu Fabra, Dr. Aiguader 88, 08003 Barcelona, Spain
| | - A Jan Hendriks
- Department of Environmental Science, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands
| | - Willie J G M Peijnenburg
- Institute of Environmental Sciences, Leiden University, 2300 RA Leiden, the Netherlands; National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven, the Netherlands
| | - Ad M J Ragas
- Department of Environmental Science, Institute for Water and Wetland Research, Radboud University, PO Box 9010, 6500 GL Nijmegen, the Netherlands; Department of Science, Faculty of Management, Science & Technology, Open University, Valkenburgerweg 177, 6419 AT Heerlen, the Netherlands
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7
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Chai L, Ji S, Zhang S, Yu H, Zhao M, Ji L. Biotransformation Mechanism of Pesticides by Cytochrome P450: A DFT Study on Dieldrin. Chem Res Toxicol 2020; 33:1442-1448. [DOI: 10.1021/acs.chemrestox.0c00013] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lihong Chai
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Shujing Ji
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
| | - Shubin Zhang
- CAS Key Laboratory of Tropical Forest Ecology, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Mengla, Yunnan 666303, China
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
| | - Haiying Yu
- College of Geography and Environmental Sciences, Zhejiang Normal University, Yingbin Avenue 688, Jinhua 321004, China
| | - Meirong Zhao
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, China
| | - Li Ji
- MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Sciences, Zhejiang University, Yuhangtang Road 866, Hangzhou 310058, China
- Graduate School of Agriculture, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto 606-8502, Japan
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8
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Fu Z, Yang L, Sun D, Qu Z, Zhao Y, Gao J, Wang Y. Coupled electron and proton transfer in the piperidine drug metabolism pathway by the active species of cytochromes P450. Dalton Trans 2020; 49:11099-11107. [DOI: 10.1039/c9dt03056e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
KS-DFT and MSDFT studies reveal a novel CEPT step that triggers ring contraction of piperidines by P450.
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Affiliation(s)
- Zhiqiang Fu
- Key Laboratory of Industrial Ecology and Environmental Engineering (MOE)
- School of Environmental Science and Technology
- Dalian University of Technology
- Dalian 116024
- China
| | - Lili Yang
- Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- China
| | - Dongru Sun
- Institute of Drug Discovery Technology
- Ningbo University
- Ningbo 315211
- China
| | - Zexing Qu
- Laboratory of Theoretical and Computational Chemistry
- Institute of Theoretical Chemistry
- Jilin University
- Changchun 130023
- China
| | - Yufen Zhao
- Institute of Drug Discovery Technology
- Ningbo University
- Ningbo 315211
- China
| | - Jiali Gao
- Department of Chemistry and Supercomputing Institute
- University of Minnesota
- Minneapolis
- USA
- Institute of Systems and Physical Biology
| | - Yong Wang
- Institute of Drug Discovery Technology
- Ningbo University
- Ningbo 315211
- China
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Cabrera-Pérez LC, Padilla-Martínez II, Cruz A, Mendieta-Wejebe JE, Tamay-Cach F, Rosales-Hernández MC. Evaluation of a new benzothiazole derivative with antioxidant activity in the initial phase of acetaminophen toxicity. ARAB J CHEM 2019. [DOI: 10.1016/j.arabjc.2016.02.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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10
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Zhang Q, Ji S, Chai L, Yang F, Zhao M, Liu W, Schüürmann G, Ji L. Metabolic Mechanism of Aryl Phosphorus Flame Retardants by Cytochromes P450: A Combined Experimental and Computational Study on Triphenyl Phosphate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:14411-14421. [PMID: 30421920 DOI: 10.1021/acs.est.8b03965] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding metabolic mechanisms is critical and remains a difficult task in the risk assessment of emerging pollutants. Triphenyl phosphate (TPHP), a widely used aryl phosphorus flame retardant (aryl-PFR), has been frequently detected in the environment, and its major metabolite was considered as diphenyl phosphate (DPHP). However, knowledge of the mechanism for TPHP leading to DPHP and other metabolites is lacking. Our in vitro study shows that TPHP is metabolized into its diester metabolite DPHP and mono- and dihydroxylated metabolites by cytochromes P450 (CYP) in human liver microsomes, while CYP1A2 and CYP2E1 isoforms are mainly involved in such processes. Molecular docking gives the conformation for TPHP binding with the active species Compound I (an iron IV-oxo heme cation radical) in specific CYP isoforms, showing that the aromatic ring of TPHP is likely to undergo metabolism. Quantum chemical calculations have shown that the dominant reaction channel is the O-addition of Compound I onto the aromatic ring of TPHP, followed by a hydrogen-shuttle mechanism leading to ortho-hydroxy-TPHP as the main monohydroxylated metabolite; the subsequent H-abstraction-OH-rebound reaction acting on ortho-hydroxy-TPHP yields the meta- and ipso-position quinol intermediates, while the former of which can be metabolized into dihydroxy-TPHP by fast protonation, and the latter species needs to go through type-I ipso-substitution and fast protonation to be evolved into DPHP. We envision that the identified mechanisms may give inspiration for studying the metabolism of several other aryl-PFRs by CYP.
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Affiliation(s)
- Quan Zhang
- College of Environment , Zhejiang University of Technology , Hangzhou 310032 , China
| | - Shujing Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Lihong Chai
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Fangxing Yang
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Meirong Zhao
- College of Environment , Zhejiang University of Technology , Hangzhou 310032 , China
| | - Weiping Liu
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , China
| | - Gerrit Schüürmann
- UFZ Department of Ecological Chemistry , Helmholtz Centre for Environmental Research , Permoserstrasse 15 , 04318 Leipzig , Germany
- Institute for Organic Chemistry , Technical University Bergakademie Freiberg , Leipziger Strasse 29 , 09596 Freiberg , Germany
| | - Li Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , China
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11
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Ji L, Ji S, Wang C, Kepp KP. Molecular Mechanism of Alternative P450-Catalyzed Metabolism of Environmental Phenolic Endocrine-Disrupting Chemicals. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:4422-4431. [PMID: 29490136 DOI: 10.1021/acs.est.8b00601] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Understanding the bioactivation mechanisms to predict toxic metabolites is critical for risk assessment of phenolic endocrine-disrupting chemicals (EDCs). One mechanism involves ipso-substitution, which may contribute to the total turnover of phenolic EDCs, yet the detailed mechanism and its relationship with other mechanisms are unknown. We used density functional theory to investigate the P450-catalyzed ipso-substitution mechanism of the prominent xenoestrogen bisphenol A. The ipso-substitution proceeds via H-abstraction from bisphenol A by Compound I, followed by essentially barrierless OH-rebound onto the ipso-position forming a quinol, which can spontaneously decompose into the carbocation and hydroquinone. This carbocation can further evolve into the highly estrogenic hydroxylated and dimer-type metabolites. The H-abstraction/OH-rebound reaction mechanism has been verified as a general reaction mode for many other phenolic EDCs, such as bisphenol analogues, alkylphenols and chlorophenols. The identified mechanism enables us to effectively distinguish between type I (eliminating-substituent as anion) and type II (eliminating-substituent as cation) ipso-substitution in various phenolic EDCs. We envision that the identified pathways will be applicable for prediction of metabolites from phenolic EDCs whose fate are affected by this alternative type of P450 reactivity, and accordingly enable the screening of these metabolites for endocrine-disrupting activity.
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Affiliation(s)
- Li Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
- UFZ Department of Ecological Chemistry , Helmholtz Centre for Environmental Research , Permoserstrasse 15 , 04318 Leipzig , Germany
| | - Shujing Ji
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
| | - Chenchen Wang
- College of Environmental and Resource Sciences , Zhejiang University , Hangzhou 310058 , P. R. China
| | - Kasper P Kepp
- DTU Chemistry , Technical University of Denmark , Building 206 , Kongens Lyngby , DK-2800 , Denmark
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12
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Zhang S, Adrian L, Schüürmann G. Interaction Mode and Regioselectivity in Vitamin B 12-Dependent Dehalogenation of Aryl Halides by Dehalococcoides mccartyi Strain CBDB1. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:1834-1843. [PMID: 29283566 DOI: 10.1021/acs.est.7b04278] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The bacterium Dehalococcoides, strain CBDB1, transforms aromatic halides through reductive dehalogenation. So far, however, the structures of its vitamin B12-containing dehalogenases are unknown, hampering clarification of the catalytic mechanism and substrate specificity as basis for targeted remediation strategies. This study employs a quantum chemical donor-acceptor approach for the Co(I)-substrate electron transfer. Computational characterization of the substrate electron affinity at carbon-halogen bonds enables discriminating aromatic halides ready for dehalogenation by strain CBDB1 (active substrates) from nondehalogenated (inactive) counterparts with 92% accuracy, covering 86 of 93 bromobenzenes, chlorobenzenes, chlorophenols, chloroanilines, polychlorinated biphenyls, and dibenzo-p-dioxins. Moreover, experimental regioselectivity is predicted with 78% accuracy by a site-specific parameter encoding the overlap potential between the Co(I) HOMO (highest occupied molecular orbital) and the lowest-energy unoccupied sigma-symmetry substrate MO (σ*), and the observed dehalogenation pathways are rationalized with a success rate of 81%. Molecular orbital analysis reveals that the most reactive unoccupied sigma-symmetry orbital of carbon-attached halogen X (σC-X*) mediates its reductive cleavage. The discussion includes predictions for untested substrates, thus providing opportunities for targeted experimental investigations. Overall, the presently introduced orbital interaction model supports the view that with bacterial strain CBDB1, an inner-sphere electron transfer from the supernucleophile B12 Co(I) to the halogen substituent of the aromatic halide is likely to represent the rate-determining step of the reductive dehalogenation.
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Affiliation(s)
- Shangwei Zhang
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technical University Bergakademie Freiberg , Institute for Organic Chemistry, Leipziger Straße 29, 09596 Freiberg, German y
| | - Lorenz Adrian
- UFZ Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technische Universität Berlin , Chair of Geobiotechnology, Ackerstraße 76, 13355 Berlin, Germany
| | - Gerrit Schüürmann
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research , Permoserstraße 15, 04318 Leipzig, Germany
- Technical University Bergakademie Freiberg , Institute for Organic Chemistry, Leipziger Straße 29, 09596 Freiberg, German y
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Zhang S, Wondrousch D, Cooper M, Zinder SH, Schüürmann G, Adrian L. Anaerobic Dehalogenation of Chloroanilines by Dehalococcoides mccartyi Strain CBDB1 and Dehalobacter Strain 14DCB1 via Different Pathways as Related to Molecular Electronic Structure. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:3714-3724. [PMID: 28233989 DOI: 10.1021/acs.est.6b05730] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Dehalococcoides mccartyi strain CBDB1 and Dehalobacter strain 14DCB1 are organohalide-respiring microbes of the phyla Chloroflexi and Firmicutes, respectively. Here, we report the transformation of chloroanilines by these two bacterial strains via dissimilar dehalogenation pathways and discuss the underlying mechanism with quantum chemically calculated net atomic charges of the substrate Cl, H, and C atoms. Strain CBDB1 preferentially removed Cl doubly flanked by two Cl or by one Cl and NH2, whereas strain 14DCB1 preferentially dechlorinated Cl that has an ortho H. For the CBDB1-mediated dechlorination, comparative analysis with Hirshfeld charges shows that the least-negative Cl discriminates active from nonactive substrates in 14 out of 15 cases and may represent the preferred site of primary attack through cob(I)alamin. For the latter trend, three of seven active substrates provide strong evidence, with partial support from three of the remaining four substrates. Regarding strain 14DCB1, the most positive carbon-attached H atom discriminates active from nonactive chloroanilines in again 14 out of 15 cases. Here, regioselectivity is governed for 10 of the 11 active substrates by the most positive H attached to the highest-charge (most positive or least negative) aromatic C carrying the Cl to be removed. These findings suggest the aromatic ring H as primary site of attack through the supernucleophile Co(I), converting an initial H bond to a full electron transfer as start of the reductive dehalogenation. For both mechanisms, one- and two-electron transfer to Cl (strain CBDB1) or H (strain 14DCB1) are compatible with the presently available data. Computational chemistry research into reaction intermediates and pathways may further aid in understanding the bacterial reductive dehalogenation at the molecular level.
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Affiliation(s)
- Shangwei Zhang
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | - Dominik Wondrousch
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | | | - Stephen H Zinder
- Department of Microbiology, Cornell University , Ithaca, New York 14853, United States
| | - Gerrit Schüürmann
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg , Leipziger Straße 29, 09596 Freiberg, Germany
| | - Lorenz Adrian
- Fachgebiet Applied Biochemistry, Technische Universität Berlin , Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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Schüürmann G, Ebert RU, Tluczkiewicz I, Escher SE, Kühne R. Inhalation threshold of toxicological concern (TTC) - Structural alerts discriminate high from low repeated-dose inhalation toxicity. ENVIRONMENT INTERNATIONAL 2016; 88:123-132. [PMID: 26735350 DOI: 10.1016/j.envint.2015.12.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 12/03/2015] [Accepted: 12/08/2015] [Indexed: 05/08/2023]
Abstract
The threshold of toxicological concern (TTC) of a compound represents an exposure value below which the associated human health risk is considered negligible. As such, this approach offers assessing the risk of potential toxicants when little or no toxicological information is available. For the inhalation repeated-dose TTC, the goal was to derive structural alerts that discriminate between high- and low-toxic compounds. A further aim was to identify physicochemical parameters related to the inhalation-specific bioavailability of the compounds, and to explore their use as predictors of high vs low toxicity. 296 compounds with subacute, subchronic and chronic inhalation toxicity NOEC (no-observed effect concentration) values were subdivided into three almost equal-sized high-, medium- and low-toxic (HTox, MTox, LTox) potency classes. Whereas the derived 14 HTox and 7 LTox structural alerts yield an only moderate discrimination between these three groups, the high-toxic vs low-toxic mis-classification is very low: LTox-predicted compounds are not HTox to 97.5%, and HTox-predicted compounds not LTox to 88.6%. The probability of a compound being HTox vs LTox is triggered further by physicochemical properties encoding the tendency to evaporate from blood. The new structural alerts may aid in the predictive inhalation toxicity assessment of compounds as well as in designing low-toxicity chemicals, and provide a rationale for the chemistry underlying the toxicological outcome that can also be used for scoping targeted experimental studies.
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Affiliation(s)
- Gerrit Schüürmann
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany; Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg, Germany.
| | - Ralf-Uwe Ebert
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
| | - Inga Tluczkiewicz
- Institute for Organic Chemistry, Technical University Bergakademie Freiberg, Leipziger Str. 29, 09596 Freiberg, Germany; Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
| | - Sylvia E Escher
- Fraunhofer Institute for Toxicology and Experimental Medicine, Nikolai-Fuchs-Str. 1, 30625 Hannover, Germany
| | - Ralph Kühne
- UFZ Department of Ecological Chemistry, Helmholtz Centre for Environmental Research, Permoserstr. 15, 04318 Leipzig, Germany
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Cooper M, Wagner A, Wondrousch D, Sonntag F, Sonnabend A, Brehm M, Schüürmann G, Adrian L. Anaerobic microbial transformation of halogenated aromatics and fate prediction using electron density modeling. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2015; 49:6018-28. [PMID: 25909816 DOI: 10.1021/acs.est.5b00303] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Halogenated homo- and heterocyclic aromatics including disinfectants, pesticides and pharmaceuticals raise concern as persistent and toxic contaminants with often unknown fate. Remediation strategies and natural attenuation in anaerobic environments often build on microbial reductive dehalogenation. Here we describe the transformation of halogenated anilines, benzonitriles, phenols, methoxylated, or hydroxylated benzoic acids, pyridines, thiophenes, furoic acids, and benzenes by Dehalococcoides mccartyi strain CBDB1 and environmental fate modeling of the dehalogenation pathways. The compounds were chosen based on structural considerations to investigate the influence of functional groups present in a multitude of commercially used halogenated aromatics. Experimentally obtained growth yields were 0.1 to 5 × 10(14) cells mol(-1) of halogen released (corresponding to 0.3-15.3 g protein mol(-1) halogen), and specific enzyme activities ranged from 4.5 to 87.4 nkat mg(-1) protein. Chlorinated electron-poor pyridines were not dechlorinated in contrast to electron-rich thiophenes. Three different partial charge models demonstrated that the regioselective removal of halogens is governed by the least negative partial charge of the halogen. Microbial reaction pathways combined with computational chemistry and pertinent literature findings on Co(I) chemistry suggest that halide expulsion during reductive dehalogenation is initiated through single electron transfer from B12Co(I) to the apical halogen site.
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Affiliation(s)
- Myriel Cooper
- †Helmholtz-Zentrum für Umweltforschung - UFZ, Department Isotope Biogeochemistry, Permoserstrasse15, 04318 Leipzig, Germany
| | - Anke Wagner
- ‡Technische Universität Berlin, Fachgebiet Applied Biochemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Dominik Wondrousch
- §Helmholtz-Zentrum für Umweltforschung - UFZ, Department Ecological Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany
- ∥Technische Universität Bergakademie Freiberg, Institute for Organic Chemistry, Leipziger Strasse 29, 09596 Freiberg, Germany
| | - Frank Sonntag
- ‡Technische Universität Berlin, Fachgebiet Applied Biochemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Andrei Sonnabend
- ‡Technische Universität Berlin, Fachgebiet Applied Biochemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
| | - Martin Brehm
- §Helmholtz-Zentrum für Umweltforschung - UFZ, Department Ecological Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany
| | - Gerrit Schüürmann
- §Helmholtz-Zentrum für Umweltforschung - UFZ, Department Ecological Chemistry, Permoserstrasse 15, 04318 Leipzig, Germany
- ∥Technische Universität Bergakademie Freiberg, Institute for Organic Chemistry, Leipziger Strasse 29, 09596 Freiberg, Germany
| | - Lorenz Adrian
- †Helmholtz-Zentrum für Umweltforschung - UFZ, Department Isotope Biogeochemistry, Permoserstrasse15, 04318 Leipzig, Germany
- ‡Technische Universität Berlin, Fachgebiet Applied Biochemistry, Gustav-Meyer-Allee 25, 13355 Berlin, Germany
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