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  8. Estatira Sepehr
  1. Science & Research (NCTR)

Estatira Sepehr Ph.D.
Leadership Role

Staff Fellow — Office of Scientific Coordination

Dr. Estatira Sepehr
Estatira Sepehr, Ph.D.

(870) 543-7121

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About  |  Publications | Lab Members


Dr. Estatira Sepehr received her B.Sc. degree in biochemistry-biotechnology and M.S. degree in chemistry with specialization in chemical and environmental toxicology from Carleton University (Ottawa, ON, Canada). There, she investigated the role of cecal bacterial fermentation on folate bioavailability in rats. Dr. Sepehr further continued her research at the University of Ottawa in bioavailability and tissue distribution of dietary soy isoflavones in rats and earned a Ph.D. in cellular and molecular medicine. She also won a federal government award for creativity and innovation in genetically modified food, presented by the Chief Scientists of Canada. Between 2007-2010, Dr. Sepehr joined the Natural Health Product Directorate at Health Canada, acting as a safety and efficacy assessment officer. In 2008, she received an Assistant Deputy Minister’s Excellence Award for contribution as an assessment officer in the Product Assessment Division of Health Canada. In 2011, she joined NCTR as an Oak Ridge Institute for Science and Technology postdoctoral fellow in the Division of Biochemical Toxicology, where she was responsible for the design and execution of appropriate research strategies. This included developing and validating an analytical methodology using state-of-the-art liquid chromatography and mass spectrometry instruments, as well as evaluating bioavailability and pharmacokinetics of active ingredients from botanical estrogens and their metabolites in animal models. In 2013, she was converted to an FDA Staff Fellow. Since then, she has been responsible for several broad and complex projects sponsored by the Center for Tobacco Products and the FDA, as well as studies funded by a Cooperative Research and Development Agreement with the University of Illinois, Auburn University, and the National Institute of Environmental Health Sciences/National Toxicology Program. Her contribution to these projects has focused on the development of innovative and sensitive liquid chromatography-mass spectrometry methods for measuring environmental chemicals and drugs (e.g. environmental phenols such as BPA, botanical estrogens, oxybenzone, nicotine, tobacco-specific nitrosamines, and doxorubicin) in a variety of biological matrices including plasma, urine, various tissues, and DNA from selected rodent tissues. Currently, she is a staff member in the Analytical Chemistry Group within the Office of Scientific Coordination. Dr. Sepehr has published many manuscripts in peer-reviewed journals, contributed to book chapters, presented many abstracts at national and international scientific meetings, and served as a reviewer for scientific publications in the field of biochemical toxicology and nutrition research. She has been consulted by researchers inside and outside FDA and has trained other staff members and visiting scientists. 

Research Interests

Dr. Sepehr’s research interests focus on an in-depth toxicological and pharmacokinetic evaluation of tobacco specific nitrosamines and nicotine, inhalation toxicity with in vivo study models, pharmacokinetics and cardiotoxicity of doxorubicin, and the safety and efficacy of botanical estrogens, mainly soy isoflavones. She specializes in the bioanalytical chemistry analysis, especially developing and validating new methods for identification and quantification of chemicals of interest to FDA using a variety of state-of-the-art instruments, such as:

  • High performance liquid chromatography mass spectrometry (HPLC/MS)
  • Ultra-pressure liquid chromatography-mass spectrometry (UPLC/MS/MS)
  • UPLC with Quadrupole Dalton (QDa) mass detector
  • HPLC with ultraviolet detector 
  • Gas chromatography-nitrogen phosphorus detection 
  • UV-visible spectroscopy
  • Automated solid phase extraction system

Professional Societies/National and International Groups 

Canadian Forum for Analytical and Bioanalytical Sciences
2020 – Present

American Society for Mass Spectrometry
2012 – Present

Canadian Society for Mass Spectrometry
2002 – Present

Selected Publications 

Rapid Quantitation of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and its Metabolite 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in Rat Urine Using Ultra-fast Liquid Chromatography Mass Spectrometry (UFLC/MS/MS). 
Sepehr E., Woodling K.A., and Bryant M.
J Liq Chromatogr Relat Technol. 2018, 41(8):422-429. 

Nitrate Reduction in Canned Apples and Pears Using Calcium Hydrogen Phosphate (CaHPO4).
Ziarati P., Sepehr E., Heidari S., and Moslehishad M.
Iran J Toxicol. 2017, 11(5): 53-59. doi: 10.29252/arakmu.11.5.53.

Histamine, Nitrate, and Nitrite Content in Canned and Fresh Apple Products. 
Ziarati P., Sepehr E., and Heidari S.
Biosci Biotech Res Asia. 2017, 14(2):827-834.  

Comparison of Endpoints Relevant to Toxicity Assessments in 3 Generations of CD-1 Mice Fed Irradiated Natural and Purified Ingredient Diets with Varying Soy Protein and Isoflavone Contents.
Camacho L., Lewis S.M., Vanlandingham M.M., Juliar B.E., Olson G.R., Patton R.E., Gamboa da Costa G., Woodling K., Sepehr E., Bryant M.S., Doerge D.R., Basavarajappa M.S., Felton R.P., and Delclos K.B.
Food Chem Toxicol. 2016, 94:39-56. doi:10.1016/j.fct.2016.05.014.

Effects of Maternal and Lactational Exposure to 2-hydroxy-4-methoxybenzone on Development and Reproductive Organs in Male and Female Rat Offspring. 
Nakamura, N., Inselman, A.L., White, G.A., Chang, C.W., Trbojevich, R.A., Sepehr, E., Voris, K.L., Patton, R.E., Bryant, M.S., Harrouk, W., McIntyre, B.S., Foster, P.M., Hansen, D.K. 
Birth Defects Res B Dev Reprod Toxicol. 2015, 104(1):35-5. PMID:25707689; doi:10.1002/bdrb.21137.

Comparison of Life-Stage-Dependent Internal Dosimetry for Bisphenol A, Ethinyl Estradiol, a Reference Estrogen, and Endogenous Estradiol to Test an Estrogenic Mode of Action in Sprague Dawley Rats.
Churchwell M.I., Camacho L., Vanlandingham M.M., Twaddle N.C., Sepehr E., Delclos K.B., Fisher J.W., and Doerge D.R.
Toxicol Sci. 2014, 139(1):4-20. PMID:24496641; doi:10.1093/toxsci/kfu021.

Testicular Development in Male Rats is Sensitive to a Soy-based Diet in the Neonatal Period.
Napier I.D., Simon L., Perry D., Cooke P.S., Stocco D.M., Sepehr E., Doerge D.R., Kemppainen B.W., Morrison E.E., and Akingbemi B.T. 
Biol Reprod. 2014, 90(2):40, 1-12. PMID:24451983; doi:10.1095/biolreprod.113.113787. 

The Effects of Dietary Treatment with S-equol on Learning and Memory Processes in Middle-aged Ovariectomized Rats.
Neese S.L., Pisani S.L., Doerge D.R., Helferich W.G., Sepehr E., Chittiboyina A.G., Rotte S.C., Smillie T.J., Khan I.A., Korol D.L., and Schantz S.L. 
Neurotoxicol Teratol. 2014, 41:80-88. PMID:24368316; doi:10.1016/j.ntt.2013.12.004.

Pharmacokinetics of the Estrogen Receptor Subtype-selective Ligands, PPT and DPN: Quantification Using UPLC-ES/MS/MS.
Sepehr E., Lebl-Rinnova M., Mann M.K., Pisani M.L., Churchwell M.I., Korol D.L., Katzenellenbogen J.A., and Doerge, D.R. 
J Pharm Biomed Anal. 2012, 71:119-126. PMID:22981216; doi:10.1016/j.jpba.2012.08.022. 

Distribution of Isoflavones in Samples of Serum, Liver and Mammary Glands of Rats or Pigs Fed Dietary Isoflavones.
Gilani G.S., Farmer C., Dyck M., Robertson P., Dahiya J., Sepehr E., Fan L., Nicolidakis H., Curran I., and Cooke G.M.
Ann Nutr Meta. 2011, 58:171-180. PMID:21654164; doi:10.1159/000328771.

Effect of Glycosidation of Isoflavones on Their Bioavailability and Pharmacokinetics in Aged Male Rats.
Sepehr E., Cooke G.M., Robertson P., and Gilani G.S.
Mol. Nutr. Food Res. 2009, 53 Suppl 1: S16-S23. PMID:19437481; doi:10.1002/mnfr.200800170.

Bioavailability of Soy Isoflavones in Rats. Part I: Application of Accurate Methodology for Studying the Effects of Gender and Source of Isoflavones.
Sepehr E., Cooke G.M., Robertson P., and Gilani G.S. 
Mol Nutr Food Res. 2007, 51 (7):799-812. PMID:17576640; doi:10.1002/mnfr.200700083. 

An Accurate Method for the Quantitative Analysis of Isoflavones and Their Metabolites in Rat Plasma Using Liquid Chromatography Combined with Mass Spectrometry and Photodiode Array Detection.
Sepehr E., Robertson P., Gilani G.S., Cooke G.M., and Lau BP.Y. 
J. AOAC International. 2006, 89 (4): 1158-1167. PMID:16915859.

Effects of Antinutritional Factors on Protein Digestibility and Amino Acid Availability in Foods.
Gilani, S.G., Cockell, K., and Sepehr, E. 
J. AOAC International. 2005, 88 (3): 967-987. PMID:16001874.

Folate Derived from Cecal Bacterial Fermentation Does Not Increase Liver Folate Stores in 28-d Folate Depleted Male Sprague-Dawley Rats.
Sepehr E., Peace R. W., Storey K. B., Jee P., Lampi B.J., and Brooks S.P.J. 
J. Nutr. 2003, 133:1347-1354. PMID:12730421; doi:10.1093/jn/133.5.1347.

Protein Digestibility and Quality in Products Containing Antinutritional Factors are Adversely Affected by Old Age in Rats.
Gilani S.G. and Sepehr E. 
J. Nutr. 2003, 133: 220-225. PMID:12514294; doi:10.1093/jn/133.1.220.

Lab Members 

Contact information for all lab members:
(870) 543-7121

Matthew Bryant, Ph.D.
Chemist (Team Leader)

Mani Chidambaram, Ph.D.
Staff Fellow

Xiaobo He, Ph.D.
Visiting Scientist

Florence McLellen, M.S.
Staff Fellow

Jasyl Nichols

Raul Trbojevich, Ph.D. 

Contact Information
Estatira Sepehr
Technology & Discipline
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