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Chai Y, Sheng D, Ji X, Meng Y, Shen F, He R, Ma R, Wang Y. Developmental and neurobehavioral toxicity of 2,2'-methylenebis(6-tert-butyl-4-methylphenol) (antioxidant AO2246) during the early life stage of zebrafish. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 899:166306. [PMID: 37586501 DOI: 10.1016/j.scitotenv.2023.166306] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/30/2023] [Accepted: 08/12/2023] [Indexed: 08/18/2023]
Abstract
BACKGROUND 2,2'-Methylenebis (4-methyl-6-tert-butylphenol) (AO2246) is a synthetic phenolic antioxidant extensively used in food packaging bags and cosmetics. Recently, AO2246 was detected with unexpectedly high concentrations in plasma and breast milk samples from pregnant and lactating women. Hence, it is essential to conduct a thorough investigation to evaluate the detrimental effects of AO2246 on biota. OBJECTIVE To investigate the developmental and behavioral toxicity of AO2246 in zebrafish, as well as the molecular mechanisms underlying these effects. METHODS Zebrafish embryos were exposed to AO2246 at concentrations ranging from 0.05 to 10 μM for up to 6 days postfertilization (dpf). Hatching rate, survival rate, heart rate, and body length were measured. Locomotor behavioral and electrophysiologal analyses were performed. Two fluorescence-labeled transgenic zebrafish lines (endothelium-Tg and macrophage/microglia-Tg) were employed. RNA sequencing was carried out. RESULTS AO2246 has a 96-hour LC50 value of 3 μM. The exposure of AO2246 resulted in a significant reduction in both hatching rate and heart rate. Analysis of locomotor behavior demonstrated that larvae exposed to AO2246 doses exceeding 2 μM exhibited a significant decrease in both total distance and mean velocity. Electrophysiological recordings demonstrated a noteworthy reduction in spike activity at a concentration of 3 μM, relative to control conditions. The administration of AO2246 at 3 μM elicited morphological reactivity and immune alteration of the midbrain microglia in the macrophage/microglia-transgenic zebrafish line, indicating a potential contribution of neurological disorders to behavioral defects. RNA sequencing analysis revealed altered gene expression profiles at high AO2246 concentrations, particularly the dysregulation of pathways associated with neuronal function. CONCLUSIONS The present study demonstrates that AO2246 exposure elicits developmental and neurobehavioral toxicity in zebrafish larvae. Specifically, exposure to AO2246 was found to cause disturbances in neuronal electrophysiological activity and neurological disorders, which ultimately led to the impairment of locomotor behavior in zebrafish larvae.
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Affiliation(s)
- Yinan Chai
- Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 311121, China; College of stomatology, Hangzhou Normal University, Hangzhou 311121, China
| | - Donglai Sheng
- Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 311121, China
| | - Xiaowei Ji
- Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 311121, China; Department of Stomatology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi 830054, China
| | - Yanlong Meng
- College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310018, China
| | - Feihao Shen
- Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 311121, China; College of stomatology, Hangzhou Normal University, Hangzhou 311121, China
| | - Rui He
- College of stomatology, Hangzhou Normal University, Hangzhou 311121, China
| | - Runjia Ma
- College of Nursing and Rehabilitation, North China University of Science and Technology, Tangshan 063210, China
| | - Yuying Wang
- Key Laboratory of Organ Development and Regeneration of Zhejiang Province, College of Life and Environmental Science, Hangzhou Normal University, Hangzhou 311121, China; College of stomatology, Hangzhou Normal University, Hangzhou 311121, China.
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Ableitung eines HBM-I-Wertes für Butylhydroxytoluol (BHT) für Erwachsene – Stellungnahme der Kommission Human-Biomonitoring des Umweltbundesamtes. Bundesgesundheitsblatt Gesundheitsforschung Gesundheitsschutz 2022; 65:946-950. [PMID: 36048211 DOI: 10.1007/s00103-022-03569-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Ao J, Wang Y, Tang W, Aimuzi R, Luo K, Tian Y, Zhang Q, Zhang J. Patterns of environmental exposure to phenols in couples who plan to become pregnant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 821:153520. [PMID: 35101495 DOI: 10.1016/j.scitotenv.2022.153520] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 01/10/2022] [Accepted: 01/25/2022] [Indexed: 06/14/2023]
Abstract
Phenols are widely used in consumer products and known for their reproductive toxicities. Little is known regarding the environmental exposure to phenols in couples prior to conception, a key period affecting fertility. We measured the urinary concentrations of six parabens and seven bisphenols in 903 pre-conception couples in China. We investigated the occurrence, distribution, source and health risk of phenols in husbands and wives separately, and the correlation and difference in phenol concentrations between couples. Similar distribution profiles of urinary phenols were observed between females and males. Methyl 4-hydroxybenzoate (MeP) and bisphenol A (BPA) were the predominant compounds. The level of urinary phenols in our population was mostly lower than the global levels. Exposure to phenols was linked to processed food and personal care products. The correlations between phenols in males and females were moderate (0.218-0.686), while the correlation in phenols between husband and wife was low (0.009-0.215). Female had a significantly higher urinary phenol levels than male (P < 0.05). Urinary phenols in couples were associated with family income, type of drinking water and frequency of household cleaning. Household factors accounted for ≤1.5% of variance in phenol levels between couples, suggesting that individual variations may be the major factor. Risk assessment showed that exposure to phenols posed a low hazard to 17.5% of the couples in our population. Our findings provide important evidence of environmental exposure to phenols in couples of child-bearing age.
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Affiliation(s)
- Junjie Ao
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Yuqing Wang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Weifeng Tang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Ruxianguli Aimuzi
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Kai Luo
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Ying Tian
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China; School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China
| | - Qianlong Zhang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China
| | - Jun Zhang
- Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China; School of Public Health, Shanghai Jiao Tong University, Shanghai 200025, China.
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Murawski A, Schmied-Tobies MIH, Rucic E, Schmidtkunz C, Küpper K, Leng G, Eckert E, Kuhlmann L, Göen T, Daniels A, Schwedler G, Kolossa-Gehring M. Metabolites of 4-methylbenzylidene camphor (4-MBC), butylated hydroxytoluene (BHT), and tris(2-ethylhexyl) trimellitate (TOTM) in urine of children and adolescents in Germany - human biomonitoring results of the German Environmental Survey GerES V (2014-2017). ENVIRONMENTAL RESEARCH 2021; 192:110345. [PMID: 33096061 DOI: 10.1016/j.envres.2020.110345] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 05/07/2023]
Abstract
The UV filter 4-methylbenzylidene camphor (4-MBC), used in cosmetics, the antioxidant butylated hydroxytoluene (BHT), used inter alia as a food additive and in cosmetics, and the plasticizer tris(2-ethylhexyl) trimellitate (TOTM), used mainly in medical devices as substitute for di-(2-ethylhexyl) phthalate (DEHP), are suspected to have endocrine disrupting effects. Human biomonitoring methods that allow for assessing the internal exposure of the general population to these substances were recently developed in a German cooperation to enhance the use of human biomonitoring. First-morning void urine samples from 3- to 17-year-old children and adolescents living in Germany were analysed for metabolites of 4-MBC (N = 447), BHT (N = 2091), and TOTM (N = 431) in the population-representative German Environmental Survey on Children and Adolescents 2014-2017 (GerES V). 4-MBC metabolites were found in quantifiable amounts only in single cases and exposure levels remained well below health-based guidance values. In contrast, ubiquitous exposure to BHT became evident with a geometric mean (GM) urinary concentration of the metabolite BHT acid of 2.346 μg/L (1.989 μg/gcreatinine) and a maximum concentration of 248 μg/L (269 μg/gcrea). The highest GM concentration was found in young children aged 3-5 years, yet no specific sources of exposure could be identified. Also, TOTM metabolites were found in quantifiable amounts only in very few samples. None of these findings could be related to previous hospital treatment or exposure via house dust. The presented results will be the basis to derive reference values for exposure of children and adolescents in Germany to BHT and will facilitate to identify changing exposure levels in the general population.
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Affiliation(s)
| | | | - Enrico Rucic
- German Environment Agency (UBA), Berlin, Germany
| | | | - Katja Küpper
- Currenta GmbH & Co. OHG, Institute of Biomonitoring, Leverkusen, Germany
| | - Gabriele Leng
- Currenta GmbH & Co. OHG, Institute of Biomonitoring, Leverkusen, Germany
| | - Elisabeth Eckert
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Laura Kuhlmann
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Thomas Göen
- Institute and Outpatient Clinic of Occupational, Social and Environmental Medicine, Friedrich-Alexander Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Anja Daniels
- German Environment Agency (UBA), Berlin, Germany
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Schmidtkunz C, Küpper K, Weber T, Leng G, Kolossa-Gehring M. A biomonitoring study assessing the exposure of young German adults to butylated hydroxytoluene (BHT). Int J Hyg Environ Health 2020; 228:113541. [DOI: 10.1016/j.ijheh.2020.113541] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/15/2020] [Accepted: 04/15/2020] [Indexed: 11/28/2022]
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Wang W, Kannan K. Quantitative identification of and exposure to synthetic phenolic antioxidants, including butylated hydroxytoluene, in urine. ENVIRONMENT INTERNATIONAL 2019; 128:24-29. [PMID: 31029976 PMCID: PMC6526070 DOI: 10.1016/j.envint.2019.04.028] [Citation(s) in RCA: 65] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/11/2019] [Accepted: 04/11/2019] [Indexed: 05/23/2023]
Abstract
Synthetic phenolic antioxidants (SPAs) such as 2,6-di-tert-butyl-4-hydroxytoluene (butylated hydroxytoluene, BHT), are used in a wide variety of consumer products, including certain foodstuffs (e.g. fats and oils) and cosmetics. Although BHT is considered generally safe as a food preservative when used at approved concentrations, there is debate whether BHT exposure is linked to cancer, asthma, and behavioral issues in children. Little is known with regard to human exposure to SPAs and the methods to measure these chemicals in urine. In this study, six SPAs and the metabolites were analyzed in 145 urine samples collected from four Asian countries (China, India, Japan, and Saudi Arabia) and the United States. BHT was found in 88% of the urine samples at median and maximum concentrations of 1.26 and 15 ng/mL, respectively. BHT metabolites and butylated hydroxyanisole (BHA) were found in 39% to 89% of the urine samples at a concentration range of
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Affiliation(s)
- Wei Wang
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, United States
| | - Kurunthachalam Kannan
- Wadsworth Center, New York State Department of Health, and Department of Environmental Health Sciences, School of Public Health, State University of New York at Albany, Empire State Plaza, P.O. Box 509, Albany, NY 12201-0509, United States; Biochemistry Department, Faculty of Science, and Experimental Biochemistry Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia.
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Nieva-Echevarría B, Manzanos MJ, Goicoechea E, Guillén MD. 2,6-Di-Tert-Butyl-Hydroxytoluene and Its Metabolites in Foods. Compr Rev Food Sci Food Saf 2014; 14:67-80. [PMID: 33401811 DOI: 10.1111/1541-4337.12121] [Citation(s) in RCA: 92] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/02/2014] [Indexed: 11/28/2022]
Abstract
2,6-Di-tert-butyl-hydroxytoluene (BHT, E-321) is a synthetic phenolic antioxidant which has been widely used as an additive in the food, cosmetic, and plastic industries for the last 70 y. Although it is considered safe for human health at authorized levels, its ubiquitous presence and the controversial toxicological data reported are of great concern for consumers. In recent years, special attention has been paid to these 14 metabolites or degradation products: BHT-CH2 OH, BHT-CHO, BHT-COOH, BHT-Q, BHT-QM, DBP, BHT-OH, BHT-OOH, TBP, BHQ, BHT-OH(t), BHT-OH(t)QM, 2-BHT, and 2-BHT-QM. These derived compounds could pose a human health risk from a food safety point of view, but they have been little studied. In this context, this review deals with the occurrence, origin, and fate of BHT in foodstuffs, its biotransformation into metabolites, their toxicological implications, their antioxidant and prooxidant properties, the analytical determination of metabolites in foods, and human dietary exposure. Moreover, noncontrolled additional sources of exposure to BHT and its metabolites are highlighted. These include their carryover from feed to fish, poultry and eggs, their presence in smoke flavorings, their migration from plastic pipelines and packaging to water and food, and their presence in natural environments, from which they can reach the food chain.
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Affiliation(s)
- Bárbara Nieva-Echevarría
- Food Technology, Faculty of Pharmacy, Lascaray Research Center, Univ. of the Basque Country (UPV/EHU), Paseo de la Universidad nº 7, 01006, Vitoria, Spain
| | - María J Manzanos
- Food Technology, Faculty of Pharmacy, Lascaray Research Center, Univ. of the Basque Country (UPV/EHU), Paseo de la Universidad nº 7, 01006, Vitoria, Spain
| | - Encarnación Goicoechea
- Food Technology, Faculty of Pharmacy, Lascaray Research Center, Univ. of the Basque Country (UPV/EHU), Paseo de la Universidad nº 7, 01006, Vitoria, Spain
| | - María D Guillén
- Food Technology, Faculty of Pharmacy, Lascaray Research Center, Univ. of the Basque Country (UPV/EHU), Paseo de la Universidad nº 7, 01006, Vitoria, Spain
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Zeliger HI. Exposure to lipophilic chemicals as a cause of neurological impairments, neurodevelopmental disorders and neurodegenerative diseases. Interdiscip Toxicol 2013; 6:103-10. [PMID: 24678247 PMCID: PMC3967436 DOI: 10.2478/intox-2013-0018] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2013] [Revised: 09/25/2013] [Accepted: 09/30/2013] [Indexed: 11/26/2022] Open
Abstract
Many studies have associated environmental exposure to chemicals with neurological impairments (NIs) including neuropathies, cognitive, motor and sensory impairments; neurodevelopmental disorders (NDDs) including autism and attention deficit hyperactivity disorder (ADHD); neurodegenerative diseases (NDGs) including Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis (ALS). The environmental chemicals shown to induce all these diseases include persistent organic pollutants (POPs), the plastic exudates bisphenol A and phthalates, low molecular weight hydrocarbons (LMWHCs) and polynuclear aromatic hydrocarbons (PAHs). It is reported here that though these chemicals differ widely in their chemical properties, reactivities and known points of attack in humans, a common link does exist between them. All are lipophilic species found in serum and they promote the sequential absorption of otherwise non-absorbed toxic hydrophilic species causing these diseases.
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Affiliation(s)
- Harold I Zeliger
- Zeliger Chemical, Toxicological, and Environmental Research, West Charlton, NY, USA
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Zeliger HI. Lipophilic chemical exposure as a cause of cardiovascular disease. Interdiscip Toxicol 2013; 6:55-62. [PMID: 24179429 PMCID: PMC3798856 DOI: 10.2478/intox-2013-0010] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2013] [Revised: 06/18/2013] [Accepted: 06/24/2013] [Indexed: 01/06/2023] Open
Abstract
Environmental chemical exposure has been linked to numerous diseases in humans. These diseases include cancers; neurological and neurodegenerative diseases; metabolic disorders including type 2 diabetes, metabolic syndrome and obesity; reproductive and developmental disorders; and endocrine disorders. Many studies have associated the link between exposures to environmental chemicals and cardiovascular disease (CVD). These chemicals include persistent organic pollutants (POPs); the plastic exudates bisphenol A and phthalates; low molecular weight hydrocarbons (LMWHCs); and poly nuclear aromatic hydrocarbons (PAHs). Here it is reported that though the chemicals reported on differ widely in chemical properties and known points of attack in humans, a common link exists between them. All are lipophilic species that are found in serum. Environmentally induced CVD is related to total lipophilic chemical load in the blood. Lipophiles serve to promote the absorption of otherwise not absorbed toxic hydrophilic species that promote CVD.
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Affiliation(s)
- Harold I Zeliger
- Zeliger Chemical, Toxicological and Environmental Research, West Charlton, New York, USA
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Vora J, Boroujerdi M. Enhanced Aqueous Solubility of Phenolic Antioxidants Using Modified β-Cyclodextrins. Drug Dev Ind Pharm 2008. [DOI: 10.3109/03639049509026638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Hu R, Shen G, Yerramilli UR, Lin W, Xu C, Nair S, Kong ANT. In vivo pharmacokinetics, activation of MAPK signaling and induction of phase II/III drug metabolizing enzymes/transporters by cancer chemopreventive compound BHA in the mice. Arch Pharm Res 2006; 29:911-20. [PMID: 17121188 DOI: 10.1007/bf02973914] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Phenolic antioxidant butylated hydroxyanisole (BHA) is a commonly used food preservative with broad biological activities, including protection against chemical-induced carcinogenesis, acute toxicity of chemicals, modulation of macromolecule synthesis and immune response, induction of phase II detoxifying enzymes, as well as its undesirable potential tumor-promoting activities. Understanding the molecular basis underlying these diverse biological actions of BHA is thus of great importance. Here we studied the pharmacokinetics, activation of signaling kinases and induction of phase II/III drug metabolizing enzymes/transporter gene expression by BHA in the mice. The peak plasma concentration of BHA achieved in our current study after oral administration of 200 mg/kg BHA was around 10 microM. This in vivo concentration might offer some insights for the many in vitro cell culture studies on signal transduction and induction of phase II genes using similar concentrations. The oral bioavailability (F) of BHA was about 43% in the mice. In the mouse liver, BHA induced the expression of phase II genes including NQO-1, HO-1, gamma-GCS, GST-pi and UGT 1A6, as well as some of the phase III transporter genes, such as MRP1 and Slcolb2. In addition, BHA activated distinct mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinase (JNK), extracellular signal-regulated protein kinase (ERK), as well as p38, suggesting that the MAPK pathways may play an important role in early signaling events leading to the regulation of gene expression including phase II drug metabolizing and some phase III drug transporter genes. This is the first study to demonstrate the in vivo pharmacokinetics of BHA, the in vivo activation of MAPK signaling proteins, as well as the in vivo induction of Phase II/III drug metabolizing enzymes/transporters in the mouse livers.
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Affiliation(s)
- Rong Hu
- Graduate Program in Pharmaceutical Science, Department of Pharmaceutics, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854, USA
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Lame ME, Kalgutkar AS, LaFontaine M. Intravenous Pharmacokinetics and Metabolism of the Reactive Oxygen Scavenger α-Phenyl-N-Tert-Butyl Nitrone (PBN) in the Cynomolgus Monkey. ACTA ACUST UNITED AC 2004; 20:11-24. [PMID: 15283300 DOI: 10.1515/dmdi.2004.20.1-2.11] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The pharmacokinetics and metabolism of the antioxidant and reactive oxygen scavenger alpha-phenyl-N-tert-butyl nitrone (PBN) was examined in the male cynomolgus monkey after intravenous administration. Following an i.v. bolus dose of 5 mg/kg, plasma concentrations of PBN declined in a bi-exponential fashion. PBN demonstrated a moderate plasma clearance (CL(p) = 27.02 +/- 6.46 ml/min/kg) and a moderate volume of distribution at steady state (Vd(ss) = 1.70 +/- 0.23 l/kg), resulting in a terminal elimination half-life of 0.76 +/- 0.25 h. The corresponding area under the curve (AUC(0-infinity)) was 3.20 +/- 0.77 microg-h/ml. Scale-up of the in vitro microsomal intrinsic clearance data for PBN afforded a blood clearance (CLb) value of 22 ml/min/kg, which was in reasonable agreement with the observed in vivo CLb. Monkey liver microsomes catalyzed the NADPH-dependent monohydroxylation of PBN to the corresponding alpha-4-hydroxyphenyl-N-tert-butylnitrone (4-HOPBN) metabolite. The formation of 4-HOPBN and its corresponding O-glucuronide was also discernible upon qualitative analysis of pooled (0-24 h) monkey plasma and urine samples. Less than 5% of the administered dose was excreted as unchanged PBN in the urine, suggesting that P450-catalyzed metabolism constituted the major route of PBN clearance in the primate. In conclusion, the pharmacokinetic attributes and the clearance mechanism of PBN in the cynomolgus monkey is similar to that observed in the Sprague-Dawley rat.
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Affiliation(s)
- Mary E Lame
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research & Development, Groton, CT 06340, USA
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Abstract
BHT is the recognized name in the cosmetics industry for butylated hydroxytoluene. BHT is used in a wide range of cosmetic formulations as an antioxidant at concentrations from 0.0002% to 0.5%. BHT does penetrate the skin, but the relatively low amount absorbed remains primarily in the skin. Oral studies demonstrate that BHT is metabolized. The major metabolites appear as the carboxylic acid of BHT and its glucuronide in urine. At acute doses of 0.5 to 1.0 g/kg, some renal and hepatic damage was seen in male rats. Short-term repeated exposure to comparable doses produced hepatic toxic effects in male and female rats. Subchronic feeding and intraperitoneal studies in rats with BHT at lower doses produced increased liver weight, and decreased activity of several hepatic enzymes. In addition to liver and kidney effects, BHT applied to the skin was associated with toxic effects in lung tissue. BHT was not a reproductive or developmental toxin in animals. BHT has been found to enhance and to inhibit the humoral immune response in animals. BHT itself was not generally considered genotoxic, although it did modify the genotoxicity of other agents. BHT has been associated with hepatocellular and pulmonary adenomas in animals, but was not considered carcinogenic and actually was associated with a decreased incidence of neoplasms. BHT has been shown to have tumor promotion effects, to be anticarcinogenic, and to have no effect on other carcinogenic agents, depending on the target organ, exposure parameters, the carcinogen, and the animal tested. Various mechanism studies suggested that BHT toxicity is related to an electrophillic metabolite. In a predictive clinical test, 100% BHT was a mild irritant and a moderate sensitizer. In provocative skin tests, BHT (in the 1% to 2% concentration range) produced positive reactions in a small number of patients. Clinical testing did not find any depigmentation associated with dermal exposure to BHT, although a few case reports of depigmentation were found. The Cosmetic Ingredient Review Expert Panel recognized that oral exposure to BHT was associated with toxic effects in some studies and was negative in others. BHT applied to the skin, however, appears to remain in the skin or pass through only slowly and does not produce systemic exposures to BHT or its metabolites seen with oral exposures. Although there were only limited studies that evaluated the effect of BHT on the skin, the available studies, along with the case literature, demonstrate no significant irritation, sensitization, or photosensitization. Recognizing the low concentration at which this ingredient is currently used in cosmetic formulations, it was concluded that BHT is safe as used in cosmetic formulations.
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Trudeau-Lame ME, Kalgutkar AS, LaFontaine M. Pharmacokinetics and metabolism of the reactive oxygen scavenger alpha-phenyl-N-tert-butylnitrone in the male Sprague-Dawley rat. Drug Metab Dispos 2003; 31:147-52. [PMID: 12527695 DOI: 10.1124/dmd.31.2.147] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The pharmacokinetics of the spin-trap alpha-phenyl-N-tert-butylnitrone (PBN) was investigated in male Sprague-Dawley rats. Plasma concentrations after i.v. administration (10 mg/kg) declined monoexponentially with a terminal half-life of 2.01 +/- 0.35 h and total plasma clearance (CL(p)) and volume of distribution at steady state (Vd(ss)) averaged 12.37 +/- 3.82 ml/min/kg and 1.74 +/- 0.5 l/kg, respectively. The observed CL(p) was in close agreement with the blood clearance (CL(b)) value (11.5 ml/min/kg) predicted from in vitro liver microsomal incubations suggesting that PBN CL(p) in rats is predominantly due to hepatic metabolism. Peak plasma concentration (C(max)) following p.o. (20 mg/kg) and s.c. (30 mg/kg) PBN administration was 7.35 +/- 1.92 and 3.56 +/- 0.66 microg/ml, whereas the area under the concentration-time curve from 0 to infinity was 23.89 +/- 5.84 and 15.96 +/- 3.10 microg-h/ml, respectively. The mean oral bioavailability of PBN was 85.63 +/- 20.93%. Biotransformation studies indicated the P450 2C11-catalyzed hydroxylation of PBN to M1. Potential sites of hydroxylation included the benzylic carbon resulting in phenyl-N-tert-butylhydroxamic acid or the phenyl ring that would afford alpha-hydroxyphenyl-N-tert-butylnitrone (HOPBN). The structure of M1 was established as alpha-4-Hydroxyphenyl-N-tert-butylnitrone (4-HOPBN) on the basis of: 1) obvious LC R(t) differences between M1 and the authentic hydroxamate standard, 2) P450 catalyzed hydroxylation of [(2)H]PBN that contained a deuterium instead of a hydrogen atom on its benzylic position and which afforded [(2)H]M1, and 3) comparison of the liquid chromatography-tandem mass spectrometry properties with a synthetic 4-HOPBN standard. We speculate that 4-HOPBN is an "active" PBN metabolite that provides an additive effect to the pharmacological action of PBN in vivo.
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Affiliation(s)
- Mary E Trudeau-Lame
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Global Research & Development, Groton, CT 06340, USA
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15
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YENTÜR G, ÖZÜDOĜRU N, BAYHAN A. A SURVEY OF BHA AND BHT LEVELS IN THREE TYPES OF FOODS COMMONLY AVAILABILE IN TURKISH MARKETS. J FOOD QUALITY 1996. [DOI: 10.1111/j.1745-4557.1996.tb00428.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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16
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Würtzen G. Scientific evaluation of the safety factor for the acceptable daily intake (ADI). Case study: butylated hydroxyanisole (BHA). FOOD ADDITIVES AND CONTAMINANTS 1993; 10:307-14. [PMID: 8359313 DOI: 10.1080/02652039309374153] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The principles of 'data-derived safety factors' are applied to toxicological and biochemical information on butylated hydroxyanisole (BHA). The calculated safety factor for an ADI is, by this method, comparable to the existing internationally recognized safety evaluations. Relevance for humans of forestomach tumours in rodents is discussed. The method provides a basis for organizing data in a way that permits an explicit assessment of its relevance.
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Affiliation(s)
- G Würtzen
- Coca-Cola International, Glostrup, Denmark
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17
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de Kok TM, Levels PJ, van Faassen A, Hazen M, ten Hoor F, Kleinjans JC. Chromatographic methods for the determination of toxicants in faeces. JOURNAL OF CHROMATOGRAPHY 1992; 580:135-59. [PMID: 1400820 DOI: 10.1016/0378-4347(92)80533-v] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Modern chromatographic techniques and their application in the determination of toxic compounds in faeces are reviewed. Faecal analysis may be of importance in toxicokinetic studies of xenobiotics in order to determine factors such as metabolism, body burden and major routes of elimination. Compounds of interest include various food constituents, drugs and occupational or environmental factors. Further, various mutagenic or carcinogenic compounds which are excreted by faeces have been indicated to represent risk factors for colorectal cancer. In this context, the chromatographic determination of the endogenously generated fecapentaenes and bile acids, both postulated etiological factors in colorectal carcinogenesis, is reviewed. For fecapentaene determination, several high-performance liquid chromatographic (HPLC) methods are available; however, the applicability of some of these methods is limited owing to insufficient separation of various isomeric forms or discrimination between fecapentaenes and their precursors. For the determination of bile acids in faeces, many chromatographic procedures have been reported, and the characteristics of the most relevant methods are compared and discussed. It is concluded that separation by gas chromatography (GC) in combination with mass spectrometry provides the highest selectivity and sensitivity. A relatively rapid alternative analysis for the determination of total and aqueous faecal bile acids is proposed. Further, methods for the determination of polycyclic aromatic hydrocarbons (PAHs) are reviewed. Although the use of radiolabelled PAHs in animal studies has many advantages, it cannot be applied for human biological monitoring and HPLC and GC provide sensitive alternatives. An HPLC method for the determination of non-metabolized PAHs in faeces is described.
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Affiliation(s)
- T M de Kok
- Department of Health Risk Analysis and Toxicology, University of Limburg, Maastricht, Netherlands
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18
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Abstract
Butylated hydroxyanisole (BHA) is a synthetic food antioxidant used to prevent oils, fats and shortenings from oxidative deterioration and rancidity. This review depicts the current knowledge on BHA. The physical and chemical characteristics of BHA are summarized and its function as a food antioxidant is made clear. The toxicological characteristics of BHA and its metabolic fate in man and animal are briefly reviewed. Special emphasis is laid on the carcinogenicity of BHA in the forestomach of rodents and to related events in the forestomach and other tissues in experimental animals. At present there is sufficient evidence for carcinogenicity of BHA, but there is hardly any indication that BHA is genotoxic. Therefore risk assessment for this epigenetic carcinogen is based on non-stochastic principles. However, the mechanism underlying the tumorigenicity of BHA is not known. In the last part of this review an attempt is made to unravel the unknown mechanism of carcinogenicity. It is hypothesized that BHA gives rise to tumor formation in rodent forestomach by inducing heritable changes in DNA. Evidence is being provided that reactive oxygen species, in particular hydroxylradicals, may play a crucial role. The key question with respect to risk assessment for BHA is whether or not the underlying mechanism is thresholded, which is important for the choice of the appropriate model to assess the risk, if any, for man and to manage any potential risk.
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Affiliation(s)
- H Verhagen
- TNO Toxicology and Nutrition Institute, Maastricht, The Netherlands
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