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Hsieh CJ, Sun M, Osborne G, Ricker K, Tsai FC, Li K, Tomar R, Phuong J, Schmitz R, Sandy MS. Cancer Hazard Identification Integrating Human Variability: The Case of Coumarin. Int J Toxicol 2019; 38:501-552. [PMID: 31845612 DOI: 10.1177/1091581819884544] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Coumarin is a naturally occurring sweet-smelling benzopyrone that may be extracted from plants or synthesized for commercial uses. Its uses include as a flavoring agent, fragrance enhancer, and odor-masking additive. We reviewed and evaluated the scientific evidence on the carcinogenicity of coumarin, integrating information from carcinogenicity studies in animals with mechanistic and other relevant data, including data from toxicogenomic, genotoxicity, and metabolism studies, and studies of human variability of a key enzyme, CYP2A6. Increases in tumors were observed in multiple studies in rats and mice in multiple tissues. Our functional pathway analysis identified several common cancer-related biological processes/pathways affected by coumarin in rat liver following in vivo exposure and in human primary hepatocytes exposed in vitro. When coumarin 7-hydroxylation by CYP2A6 is compromised, this can lead to a shift in metabolism to the 3,4-epoxidation pathway and increased generation of electrophilic metabolites. Mechanistic data align with 3 key characteristics of carcinogens, namely formation of electrophilic metabolites, genotoxicity, and induction of oxidative stress. Considerations of metabolism, human variability in CYP2A6 activity, and coumarin hepatotoxicity in susceptible individuals provide additional support for carcinogenicity concern. Our analysis illustrates the importance of integrating information on human variability in the cancer hazard identification process.
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Affiliation(s)
- ChingYi Jennifer Hsieh
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Meng Sun
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Gwendolyn Osborne
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Karin Ricker
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Feng C Tsai
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Kate Li
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Rajpal Tomar
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA.,Retired
| | - Jimmy Phuong
- Department of Biomedical and Health Informatics, University of Washington, Seattle, WA, USA
| | - Rose Schmitz
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
| | - Martha S Sandy
- Office of Environmental Health Hazard Assessment, CalEPA, Sacramento and Oakland, CA, USA
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Mertens-Talcott SU, Zadezensky I, De Castro WV, Derendorf H, Butterweck V. Grapefruit-Drug Interactions: Can Interactions With Drugs Be Avoided? J Clin Pharmacol 2013; 46:1390-416. [PMID: 17101740 DOI: 10.1177/0091270006294277] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Grapefruit is rich in flavonoids, which have been demonstrated to have a preventive influence on many chronic diseases, such as cancer and cardiovascular disease. However, since the early 1990s, the potential health benefits of grapefruit have been overshadowed by the possible risk of interactions between drugs and grapefruit and grapefruit juice. Several drugs interacting with grapefruit are known in different drug classes, such as HMG-CoA reductase inhibitors, calcium antagonists, and immunosuppressives. Currently known mechanisms of interaction include the inhibition of cytochrome P450 as a major mechanism, but potential interactions with P-glycoprotein and organic anion transporters have also been reported. This review is designed to provide a comprehensive summary of underlying mechanisms of interaction and human clinical trials performed in the area of grapefruit drug interactions and to point out possible replacements for drugs with a high potential for interactions.
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Affiliation(s)
- S U Mertens-Talcott
- Department of Pharmaceutics, Center for Food Drug Interaction Research and Education, University of Florida, Gainesville, FL 32610-0494, USA
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Association between daily cigarette consumption and hypertension moderated by CYP2A6 genotypes in Chinese male current smokers. J Hum Hypertens 2012; 27:24-30. [PMID: 22217675 DOI: 10.1038/jhh.2011.111] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to assess whether cytochrome P450 enzyme 2A6 (CYP2A6) genotypes moderate the association between smoking and hypertension. In this study, 954 Chinese male current smokers from a community-based chronic disease screening project in Guangzhou were interviewed with a structured questionnaire about socio-demographic status, smoking and other health-related behaviors. Blood was collected for DNA extraction and CYP2A6 genotyping. Hypertension was defined according to 2007 ESH-ESC Practice Guidelines. A multivariate logistic regression was performed to examine the interaction between smoking quantity and CYP2A6 genotypes on hypertension after adjusting for age, education level and other potential confounders. Multivariate analyses indicated that smoking more than 15 cigarettes per day significantly increased the risk of hypertension (odds ratio (OR)=1.59, 95% confidence interval (CI)=1.21-2.10) compared with smoking 1-15 cigarettes per day, and further suggested that smoking interacted with normal CYP2A6 metabolizer genotype to increase the risk of hypertension. Smokers consuming more than 15 cigarettes per day with normal CYP2A6 metabolizer genotypes had the highest risk of hypertension (OR=2.04, 95% CI=1.11-3.75) compared with those consuming 1-15 cigarettes per day with slower CYP2A6 metabolizer genotypes. These findings demonstrated that smoking quantity was positively associated with hypertension and that CYP2A6 genotypes may moderate this relationship.
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Liu T, David SP, Tyndale RF, Wang H, Zhou Q, Ding P, He YH, Yu XQ, Chen W, Crump C, Wen XZ, Chen WQ. Associations of CYP2A6 genotype with smoking behaviors in southern China. Addiction 2011; 106:985-94. [PMID: 21205058 PMCID: PMC3074015 DOI: 10.1111/j.1360-0443.2010.03353.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To investigate the association of CYP2A6 genetic polymorphisms with smoking-related phenotypes in Chinese smokers. DESIGN Case-only genetic association study. SETTING Southern China. PARTICIPANTS A total of 1328 Han Chinese smokers who participated in a community-based chronic disease screening project in Guangzhou and Zhuhai from 2006 to 2007. MEASUREMENTS All participants answered a structured questionnaire about socio-demographic status and smoking behaviors and informative alleles were genotyped for the cytochrome P450 2A6 (CYP2A6) gene (CYP2A6*4,*5,*7,*9 and *10). FINDINGS The frequencies of CYP2A6*4, *5, *7, *9 and *10 alleles were 8.5, 1.2, 6.3, 13.5 and 2.4%, which corresponded to 48.9, 15.4, 24.2 and 11.5% of participants being classified as normal, intermediate, slow and poor metabolizers, respectively. Multivariate analyses in male smokers demonstrated that compared with normal metabolizers, poor metabolizers reported smoking fewer cigarettes per day [adjusted odds ratio (OR) = 0.49; 95% confidence interval (CI): 0.32-0.76], started smoking regularly later in life (adjusted OR = 1.55; 95% CI: 1.06-2.26) and, among former smokers, reported smoking for a shorter duration prior to quitting (adjusted OR = 0.33; 95% CI: 0.12-0.94). However, poor metabolizers were less likely to quit smoking and remain abstinent than normal metabolizers (adjusted OR = 0.54; 95% CI: 0.34-0.86). CONCLUSIONS Reduced metabolism function of cytochrome P450 2A6 in smokers appears to be associated with fewer cigarettes smoked, later initiation of smoking regularly, shorter smoking duration and lower likelihood of smoking cessation.
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Affiliation(s)
- Tao Liu
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Sean P. David
- Center for Education in Family & Community Medicine and the Division of Family & Community Medicine, Stanford University, 1215 Welch Road, Modular G, Stanford, CA 94305, USA, SRI International, 333 Ravenswood Ave, Menlo Park, CA 943025, USA, Center for Primary Care & Prevention and the Department of Family Medicine, Brown Alpert Medical School, 111 Brewster Street, Pawtucket, RI 02860
| | - Rachel F. Tyndale
- The Center for Addiction and Mental Health and the Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Canada M5S 1A8
| | - Hui Wang
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Qian Zhou
- The Center for Addiction and Mental Health and the Departments of Psychiatry, Pharmacology and Toxicology, University of Toronto, Canada M5S 1A8
| | - Peng Ding
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Yan-Hui He
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China
| | - Xue-Qing Yu
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, 58, Zhongshan Road 2, 510080, Guangzhou, China
| | - Wei Chen
- Department of Nephrology, The First Affiliated Hospital of Sun Yat-Sen University, 58, Zhongshan Road 2, 510080, Guangzhou, China
| | - Casey Crump
- Center for Education in Family & Community Medicine and the Division of Family & Community Medicine, Stanford University, 1215 Welch Road, Modular G, Stanford, CA 94305, USA
| | - Xiao-Zhong Wen
- Department of Community Health, Brown University, Providence, RI, USA
| | - Wei-Qing Chen
- Department of Biostatistics and Epidemiology, School of Public Health, Sun Yat-Sen University, 74, Zhongshan Road 2, 510080, Guangzhou, China,To whom correspondence should be addressed. Tel: +8620 87332199; Fax: +8620 87330446, (Wei-Qing Chen)
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The antigenotoxic effects of grapefruit juice on the damage induced by benzo(a)pyrene and evaluation of its interaction with hepatic and intestinal Cytochrome P450 (Cyp)1a1. Food Chem Toxicol 2011; 49:807-11. [DOI: 10.1016/j.fct.2010.11.047] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 11/20/2010] [Accepted: 11/30/2010] [Indexed: 11/20/2022]
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Abstract
Nicotine underlies tobacco addiction, influences tobacco use patterns, and is used as a pharmacological aid to smoking cessation. The absorption, distribution and disposition characteristics of nicotine from tobacco and medicinal products are reviewed. Nicotine is metabolized primarily by the liver enzymes CYP2A6, UDPglucuronosyltransferase (UGT), and flavin-containing monooxygenase (FMO). In addition to genetic factors, nicotine metabolism is influenced by diet and meals, age, sex, use of estrogen-containing hormone preparations, pregnancy and kidney disease, other medications, and smoking itself. Substantial racial/ethnic differences are observed in nicotine metabolism, which are likely influenced by both genetic and environmental factors. The most widely used biomarker of nicotine intake is cotinine, which may be measured in blood, urine, saliva, hair, or nails. The current optimal plasma cotinine cut-point to distinguish smokers from non-smokers in the general US population is 3 ng ml(-1). This cut-point is much lower than that established 20 years ago, reflecting less secondhand smoke exposure due to clear air policies and more light or occasional smoking.
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Affiliation(s)
- Neal L Benowitz
- Division of Clinical Pharmacology and Experimental Therapeutics, University of California, San Francisco, P. O. Box 1220, San Francisco, CA 94143-1220, USA.
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Malaiyandi V, Lerman C, Benowitz NL, Jepson C, Patterson F, Tyndale RF. Impact of CYP2A6 genotype on pretreatment smoking behaviour and nicotine levels from and usage of nicotine replacement therapy. Mol Psychiatry 2006; 11:400-9. [PMID: 16402128 DOI: 10.1038/sj.mp.4001794] [Citation(s) in RCA: 144] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We investigated the effect of slow metabolism of nicotine, predicted by CYP2A6 genotypes resulting in less than or equal to 50% activity, on baseline smoking behaviours and treatment variables in an open-label nicotine replacement therapy (NRT) clinical trial. Caucasian smokers with CYP2A6 slow vs normal metabolism had lower metabolic activity, indicated by the 3-hydroxycotinine/cotinine ratio (0.23+/-0.17 vs 0.45+/-0.22, P<0.01, respectively). CYP2A6 slow metabolizers also smoked fewer cigarettes per day compared to normal metabolizers (20+/-7 vs 24+/-10, respectively, P<0.04). With nicotine patch use, slow metabolizers had higher nicotine plasma levels compared to normal metabolizers (22.8+/-4.6 vs 15.8+/-7.6 ng/ml, respectively, P=0.02) while using the same numbers of patches/week. With nicotine spray use, where like in smoking the nicotine intake can be easily adjusted to adapt to rates of metabolism, slow metabolizers achieved similar nicotine levels compared to normal metabolizers (5.8+/-4.1 vs 8.0+/-9.1 ng/ml, P=0.82), by using fewer doses of nicotine spray/day (4.8+/-3.6 vs 10.5+/-8.0, respectively, P<0.02). These findings indicate that CYP2A6 genotype influences smoking behaviour in a Caucasian treatment-seeking population and that CYP2A6 genotype affects plasma levels obtained from, and usage of, NRT.
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Affiliation(s)
- V Malaiyandi
- Centre for Addiction and Mental Health and Department of Pharmacology, University of Toronto, Toronto, ON, Canada
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Abstract
Nicotine is of importance as the addictive chemical in tobacco, pharmacotherapy for smoking cessation, a potential medication for several diseases, and a useful probe drug for phenotyping cytochrome P450 2A6 (CYP2A6). We review current knowledge about the metabolism and disposition kinetics of nicotine, some other naturally occurring tobacco alkaloids, and nicotine analogs that are under development as potential therapeutic agents. The focus is on studies in humans, but animal data are mentioned when relevant to the interpretation of human data. The pathways of nicotine metabolism are described in detail. Absorption, distribution, metabolism, and excretion of nicotine and related compounds are reviewed. Enzymes involved in nicotine metabolism including cytochrome P450 enzymes, aldehyde oxidase, flavin-containing monooxygenase 3, amine N-methyltransferase, and UDP-glucuronosyltransferases are represented, as well as factors affecting metabolism, such as genetic variations in metabolic enzymes, effects of diet, age, gender, pregnancy, liver and kidney diseases, and racial and ethnic differences. Also effects of smoking and various inhibitors and inducers, including oral contraceptives, on nicotine metabolism are discussed. Due to the significance of the CYP2A6 enzyme in nicotine clearance, special emphasis is given to the effects and population distributions of CYP2A6 alleles and the regulation of CYP2A6 enzyme.
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Affiliation(s)
- Janne Hukkanen
- Division of Clinical Pharmacology and Experimental Therapeutics, Medical Service, San Francisco Genreral Hospital Medical Center, and the Department of Medicine, University of California, San Francisco, Box 1220, San Francisco, CA 94143-1220, USA
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Abstract
This review reports the last decade acquisitions on grapefruit. New coumarins and limonoids were isolated and characterised. The bioavailability of many drugs was tested with grapefruit juice (GJ) coadministration; the inhibition on cytochrome P450 seems due to a synergic action between flavonoids and coumarins. Antimicrobial, antifeeding, insecticidal, and antitumour activities were also reported.
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Affiliation(s)
- B Tirillini
- Istituto di Botanica, Università di Urbino Via Bramante, 28-61029, Urbino, Italy
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Tassaneeyakul W, Guo LQ, Fukuda K, Ohta T, Yamazoe Y. Inhibition selectivity of grapefruit juice components on human cytochromes P450. Arch Biochem Biophys 2000; 378:356-63. [PMID: 10860553 DOI: 10.1006/abbi.2000.1835] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Five compounds including furanocoumarin monomers (bergamottin, 6', 7'-dihydroxybergamottin (DHB)), furanocoumarin dimers (4-¿¿6-hydroxy-71-¿(1-hydroxy-1-methyl)ethyl-4-methyl-6-(7-oxo-7H- furo¿3,2-g1benzopyran-4-yl)-4-hexenyl]oxy]-3,7-dimethyl- 2-octenyl]oxy]-7H-furo[3,2-g]¿1benzopyran-7-one (GF-I-1) and 4-¿¿6-hydroxy-7¿¿4-methyl-1-(1-methylethenyl)-6-(7-oxo-7H-furo¿3, 2-g1benzopyran-4-yl)-4-hexenylŏxy-3, 7-dimethyl-2-octenylŏxy-7H-furo¿3,2-g1benzopyran-7-one (GF-I-4)), and a sesquiterpene nootkatone have been isolated from grapefruit juice and screened for their inhibitory effects toward human cytochrome P450 (P450) forms using selective substrate probes. Addition of ethyl acetate extract of grapefruit juice into an incubation mixture resulted in decreased activities of CYP3A4, CYP1A2, CYP2C9, and CYP2D6. All four furanocoumarins clearly inhibited CYP3A4-catalyzed nifedipine oxidation in concentration- and time-dependent manners, suggesting that these compounds are mechanism-based inhibitors of CYP3A4. Of the furanocoumarins investigated, furanocoumarin dimers, GF-I-1 and GF-I-4, were the most potent inhibitors of CYP3A4. Inhibitor concentration required for half-maximal rate of inactivation (K(I)) values for bergamottin, DHB, GF-I-1, and GF-I-4 were calculated, respectively, as 40.00, 5. 56, 0.31, and 0.13 microM, whereas similar values were observed on their inactivation rate constant at infinite concentration of inhibitor (k(inact), 0.05-0.08 min(-1)). Apparent selectivity toward CYP3A4 does occur with the furanocoumarin dimers. In contrast, bergamottin showed rather stronger inhibitory effect on CYP1A2, CYP2C9, CYP2C19, and CYP2D6 than on CYP3A4. DHB inhibited CYP3A4 and CYP1A2 activities at nearly equivalent potencies. Among P450 forms investigated, CYP2E1 was the least sensitive to the inhibitory effect of furanocoumarin components. A sesquiterpene nootkatone has no significant effect on P450 activities investigated except for CYP2A6 and CYP2C19 (K(i) = 0.8 and 0.5 microM, respectively).
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Affiliation(s)
- W Tassaneeyakul
- Department of Pharmacology, KhonKaen University, KhonKaen, 40002, Thailand
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Tassaneeyakul W, Tassaneeyakul W, Vannaprasaht S, Yamazoe Y. Formation of omeprazole sulphone but not 5-hydroxyomeprazole is inhibited by grapefruit juice. Br J Clin Pharmacol 2000; 49:139-44. [PMID: 10671908 PMCID: PMC2014902 DOI: 10.1046/j.1365-2125.2000.00122.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
AIMS To determine the effect of grapefruit juice on omeprazole metabolism in vivo. METHODS This was a randomized crossover study with a 2 week washout period. Omeprazole (20 mg) was taken orally by 13 healthy volunteers after an overnight fast with either grapefruit juice or water. Serial blood samples were obtained over 12 h and standardized meals were served 3 and 10 h after the administration of omeprazole. Plasma concentrations of omeprazole and its major metabolites, 5-hydroxyomeprazole and omeprazole sulphone, were determined by high performance liquid chromatography (h.p.l.c.). RESULTS Mean area under the plasma concentration vs time curve (AUC) between 0 and 12 h for omeprazole sulphone was approximately 20% lower (P<0.01) in the group receiving grapefruit juice. There was no significant difference in the mean AUC of 5-hydroxyomeprazole or omeprazole. The AUC ratio of omeprazole sulphone to omeprazole, an index of CYP3A4 activity, was decreased by 33% (P<0.001) after administration of grapefruit juice whereas the AUC ratio of 5-hydroxyomeprazole to omeprazole, an index of CYP2C19 activity, did not differ between the two phases of the study. Although the time to peak concentration (tmax ) and terminal half-life (t1/2,z) of omeprazole and its two main metabolites were not altered, the peak concentration (Cmax ) of omeprazole sulphone was significantly reduced after administration of grapefruit juice. CONCLUSION Administration of grapefruit juice decreased the formation of omeprazole sulphone but not 5-hydroxyomeprazole. These results indicate that activities of CYP3A4, but not of CYP2C19, are inhibited by the simultaneous administration of grapefruit juice.
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Affiliation(s)
- Wichittra Tassaneeyakul
- Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku UniversitySendai, Japan
- Department of Pharmacology, Faculty of Medicine, KhonKaen UniversityKhonKaen, Thailand
| | - Wongwiwat Tassaneeyakul
- Department of Toxicology, Faculty of Pharmaceutical Sciences, KhonKaen UniversityKhonKaen, Thailand
| | - Suda Vannaprasaht
- Department of Pharmacology, Faculty of Medicine, KhonKaen UniversityKhonKaen, Thailand
| | - Yasushi Yamazoe
- Division of Drug Metabolism and Molecular Toxicology, Graduate School of Pharmaceutical Sciences, Tohoku UniversitySendai, Japan
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Bourian M, Runkel M, Krisp A, Tegtmeier M, Freudenstein J, Legrum W. Naringenin and interindividual variability in interaction of coumarin with grapefruit juice. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 1999; 51:289-93. [PMID: 10445384 DOI: 10.1016/s0940-2993(99)80008-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
UNLABELLED Grapefruit juice has been shown to enhance oral bioavailability of several drugs including coumarin. The degree of the interaction is highly variable among the individuals. OBJECTIVE The aim of the study was to evaluate the interindividual variability in the pharmacokinetic profile of three components of grapefruit juice (naringin/naringenin, scopoletin, umbelliferone) and to compare it with the pattern of coumarin-grapefruit juice interaction. STUDY DESIGN A two-set clinical study with the participation of 18 healthy volunteers was designed. In the first set of the experiment the total renal recovery of naringenin, scopoletin and umbelliferone within 13 hours after the intake of 1L grapefruit juice was estimated. Four individuals, who had demonstrated extremely high or extremely low excretion of the metabolites in the first set, were selected for the second set. The subjects took 10 mg coumarin with 1L grapefruit juice vs 10 mg coumarin with 1 L water in a cross-over manner. The interaction pattern was evaluated according to the time-course curves of 7-hydroxycoumarin (main metabolite of coumarin) excreted with urine. The detailed time-course excretory profiles of naringenin and scopoletin from grapefruit juice were also obtained. RESULTS The screening demonstrated a significant interindividual variability in the renal excretion of naringenin (max/min > 15), scopoletin (max/min = 6.2), umbelliferone (max/min = 3.3). The interaction between coumarin and grapefruit juice has been observed by increase in the total recovery of 7-hydroxycoumarin up to 3 mg and by delay in time of its excretion by 2-3 hours. This interaction has been observed in 3 of 4 subjects and correlated with naringenin amounts in the urine. The mechanism and the sites of the interaction, as well as the causes for its wide interindividual variability are discussed in the paper.
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Affiliation(s)
- M Bourian
- Institute of Pharmacology and Toxicology, Philipps University Marburg, Germany
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