National Toxicology Program Toxicity Report Series Number 82 NTP Technical Report on the 3-Month Toxicity Studies of Estragole (CAS No. 140-67-0) Administered by Gavage to F344/N Rats and B6C3F1 Mice National Institutes of Health Public Health Service U.S. Department of Health and Human Services FOREWORD The National Toxicology Program (NTP) is an interagency program within the Public Health Service (PHS) of the Department of Health and Human Services (HHS) and is headquartered at the National Institute of Environmental Health Sciences of the National Institutes of Health (NIEHS/NIH). Three agencies contribute resources to the program: NIEHS/NIH, the National Institute for Occupational Safety and Health of the Centers for Disease Control and Prevention (NIOSH/CDC), and the National Center for Toxicological Research of the Food and Drug Administration (NCTR/FDA). Established in 1978, the NTP is charged with coordinating toxicological testing activities, strengthening the science base in toxicology, developing and validating improved testing methods, and providing information about potentially toxic substances to health regulatory and research agencies, scientific and medical communities, and the public. The Toxicity Study Report series began in 1991. The studies described in the Toxicity Study Report series are designed and conducted to characterize and evaluate the toxicologic potential of selected substances in laboratory animals (usually two species, rats and mice). Substances selected for NTP toxicity studies are chosen primarily on the basis of human exposure, level of production, and chemical structure. The interpretive conclusions presented in the Toxicity Study Reports are based only on the results of these NTP studies. Extrapolation of these results to other species, including characterization of hazards and risks to humans, requires analyses beyond the intent of these reports. Selection per se is not an indicator of a substance’s toxic potential. The NTP conducts its studies in compliance with its laboratory health and safety guidelines and FDA Good Laboratory Practice Regulations and must meet or exceed all applicable federal, state, and local health and safety regulations. Animal care and use are in accordance with the Public Health Service Policy on Humane Care and Use of Animals. Studies are subjected to retrospective quality assurance audits before being presented for public review. NTP Toxicity Study Reports are indexed in the NIH/NLM PubMed database and are available free of charge electronically on the NTP website (http://ntp.niehs.nih.gov) or in hardcopy upon request from the NTP Central Data Management group at [email protected] or (919) 541-3419. National Toxicology Program Toxicity Report Series Number 82 NTP Technical Report on the 3-Month Toxicity Studies of Estragole (CAS No. 140-67-0) Administered by Gavage to F344/N Rats and B6C3F1 Mice Douglas W. Bristol, Ph.D., Study Scientist National Toxicology Program Post Office Box 12233 Research Triangle Park, NC 27709 NIH Publication No. 11-5966 National Institutes of Health Public Health Service U.S. Department of Health and Human Services 2 CONTRIBUTORS National Toxicology Program Dynamac Corporation Evaluated and interpreted results and reported findings Prepared quality assessment audits D.W. Bristol, Ph.D., Study Scientist S. Brecher, Ph.D., Principal Investigator J.C. Peckham, D.V.M., M.S., Ph.D., Study Pathologist S. Iyer, B.S. Experimental Pathology Laboratories, Inc. V.S. Tharakan, D.V.M. J.R. Bucher, Ph.D. R.S. Chhabra, Ph.D. P.M. Foster, Ph.D. NTP Pathology Working Group R.A. Herbert, D.V.M., Ph.D. Evaluated slides and contributed to pathology report M.J. Hooth, Ph.D. (May 1, 2003) A.P. King-Herbert, D.V.M. J.C. Turnier, V.M.D., Coordinator G.E. Kissling, Ph.D. Pathology Associates, A Charles River Company D.E. Malarkey, D.V.M., Ph.D. G.P. Flake, M.D. M.C. Rhodes, Ph.D. National Toxicology Program J.M. Sanders, Ph.D. M.A. Hanes, D.V.M. C.S. Smith, Ph.D. ILS, Inc. G.S. Travlos, D.V.M. R.A. Herbert, D.V.M., Ph.D. M.K. Vallant, B.S., M.T. National Toxicology Program N.J. Walker, Ph.D. D.E. Malarkey, D.V.M., Ph.D. K.L. Witt, M.S. National Toxicology Program G. Pearse, B.V.M. & S. National Toxicology Program J.C. Peckham, D.V.M., M.S., Ph.D. Battelle Columbus Operations Experimental Pathology Laboratories, Inc. Conducted studies and evaluated pathology findings R.C. Sills, D.V.M., Ph.D. National Toxicology Program M.R. Hejtmancik, Ph.D., Principal Investigator L.M. Fomby, D.V.M., Ph.D. J.D. Johnson, Ph.D. Constella Group, Inc. M.J. Ryan, D.V.M., Ph.D. Provided statistical analyses D.Y. Vasconcelos, D.V.M., Ph.D. T.A. Peace, D.V.M., M.S. P.W. Crockett, Ph.D., Principal Investigator L.J. Betz, M.S. K.P. McGowan, M.B.A. Experimental Pathology Laboratories, Inc. Provided pathology review Biotechnical Services, Inc. M.H. Hamlin, II, D.V.M., Principal Investigator Prepared Toxicity Study Report J.C. Peckham, D.V.M., M.S., Ph.D. S.R. Gunnels, M.A., Principal Investigator L.M. Harper, B.S. J.I. Powers, M.A.P. D.C. Serbus, Ph.D. G.E. Simmons, M.A. 3 CONTENTS ABSTRACT . 5 INTRODUCTION . 11 Chemical and Physical Properties . 11 Production, Use, and Human Exposure . 13 Regulatory Status . 13 Absorption, Distribution, Metabolism, and Excretion . 14 Toxicity . 17 Reproductive and Developmental Toxicity . 18 Carcinogenicity . 18 Genetic Toxicity . 21 Study Rationale . 22 MATERIALS AND METHODS . 25 Procurement and Characterization of Estragole . 25 Preparation and Analysis of Dose Formulations . 25 3-Month Studies . 26 Statistical Methods . 31 Quality Assurance Methods . 31 Genetic Toxicology . 31 RESULTS . 35 Rats . 35 Mice . 50 Genetic Toxicology . 55 DISCUSSION . 57 REFERENCES . 63 APPENDIXES Appendix A Summary of Neoplasms and Nonneoplastic Lesions in Rats and Mice . 75 Appendix B Genetic Toxicology . 87 Appendix C Clinical Pathology Results . 91 Appendix D Organ Weights and Organ-Weight-to-Body-Weight Ratios . 99 Appendix E Chemical Characterization and Dose Formulation Studies . 103 4 Estragole, NTP TOX 82 SUMMARY Background Estragole occurs naturally in a variety of foods and spices such as basil, tarragon, bay leaves, fennel, and anise, and it is used as an additive, flavoring agent, and fragrance in a variety of foods, cleaning products, and cosmetics. It is related in structure to methyleugenol and isoeugenol, which have been shown to cause cancer in rodents. We studied estragole to determine the possible toxic effects on rats and mice after 3 months of exposure. Methods We gave groups of 10 male and 10 female rats and mice corn oil solutions containing estragole 5 days per week for 3 months by depositing the solutions directly into their stomachs through a tube. The doses delivered daily were 37.5, 75, 150, 300, or 600 milligrams of estragole per kilogram of body weight. Similar groups of 10 animals received corn oil without chemical and served as the control group. At the end of the study, tissues from the animals were examined microscopically for lesions. Results All male rats receiving 75 mg/kg or more and all female rats receiving 150 mg/kg or more developed hepatocellular hypertrophy of the liver. Three male rats receiving 600 mg/kg developed cancers of the liver within 3 months. Degeneration of the olfactory epithelium of the nose was seen in rats receiving 300 or 600 mg/kg. Atrophy of the gastric glands of the stomach, cytoplasmic alteration of the salivary glands, and pigmentation and regeneration of renal tubules of the kidney were also observed in rats exposed to estragole. Exposed mice also had noncancerous lesions of the liver and nose and, for female mice, of the stomach. Conclusion Exposure to estragole for only 3 months caused cancer of the liver in three out of 10 male rats given 600 mg/kg. Other nonneoplastic lesions were observed in the liver, stomach, nose, kidney and salivary gland of male and female rats and in the liver and nose of male and female mice. 5 ABSTRACT Estragole CAS No. 140-67-0 Chemical Formula: C10 H 12 O Molecular Weight: 148.20 IUPAC Name: 1-methoxy-4-prop-2-enylbenzene Synonyms: 1-methoxy-4-(2-propenyl)-benzene (9CI); 1-allyl-4-methoxybenzene; 3-(p-methoxyphenyl)propene; 4-allylanisole; 4-allyl- 1-methoxybenzene; chavicol methyl ether; esdragol; 1-methoxy-4-(2-propenyl)-benzene; p-methoxyallylbenzene; 4-methoxy-2N- propenylbenzene; p-allyl-methyl chavicol; tarragon IUPAC International Chemical Identifier: -InChI=1/C10H12O/c1-3-4-9-5-7-10(11-2)8-6-9/h3,5-8H,1,4H2,2H3 Canonical SMILES: c1(ccc(OC)cc1)CC=C Estragole is a natural organic compound that is used as an additive, flavoring agent, or fragrance in a variety of food, cleaning, and cosmetic products; as an herbal medicine; as an antimicrobial agent against acid-tolerant food microflora; and to produce synthetic anise oil. Estragole was nominated for toxicity testing by the National Institute of Environmental Health Sciences to characterize its toxicity when administered by gavage to F344/N rats and B6C3F1 mice and to determine how similar its effects might be to those of the structurally related compound, methyleugenol. Male and female F344/N rats and B6C3F1 mice were given estragole (greater than 99% pure) in corn oil by gavage for 3 months. Genetic toxicology studies were conducted in Salmonella typhimurium and mouse peripheral blood erythrocytes. Core and special study (rats only) groups of 10 male and 10 female rats and mice were administered 37.5, 75, 150, 300, or 600 mg estragole/kg body weight in corn oil by gavage, 5 days per week. The core study groups were given estragole for 3 months and the special study groups for 30 days.