Parabens as urinary biomarkers of exposure in humans.

Content Provider	Europe PMC
Author	Ye, Xiaoyun Bishop, Amber M. Reidy, John A. Needham, Larry L. Calafat, Antonia M.
Copyright Year	2006
Abstract	BackgroundParabens appear frequently as antimicrobial preservatives in cosmetic products, in pharmaceuticals, and in food and beverage processing. In vivo and in vitro studies have revealed weak estrogenic activity of some parabens. Widespread use has raised concerns about the potential human health risks associated with paraben exposure.ObjectivesAssessing human exposure to parabens usually involves measuring in urine the conjugated or free species of parabens or their metabolites. In animals, parabens are mostly hydrolyzed to p-hydroxybenzoic acid and excreted in the urine as conjugates. Still, monitoring urinary concentrations of p-hydroxybenzoic acid is not necessarily the best way to assess exposure to parabens. p-Hydroxybenzoic acid is a nonspecific biomarker, and the varying estrogenic bioactivities of parabens require specific biomarkers. Therefore, we evaluated the use of free and conjugated parent parabens as new biomarkers for human exposure to these compounds.ResultsWe measured the urinary concentrations of methyl, ethyl, n-propyl, butyl (n- and iso-), and benzyl parabens in a demographically diverse group of 100 anonymous adults. We detected methyl and n-propyl parabens at the highest median concentrations (43.9 ng/mL and 9.05 ng/mL, respectively) in nearly all (> 96%) of the samples. We also detected other parabens in more than half of the samples (ethyl, 58%; butyl, 69%). Most important, however, we found that parabens in urine appear predominantly in their conjugated forms.ConclusionsThe results, demonstrating the presence of urinary conjugates of parabens in humans, suggest that such conjugated parabens could be used as exposure biomarkers. Additionally, the fact that conjugates appear to be the main urinary products of parabens may be important for risk assessment.
ISSN	00916765
Journal	Environmental Health Perspectives
Volume Number	114
PubMed Central reference number	PMC1764178
Issue Number	12
PubMed reference number	17185273
e-ISSN	15529924
DOI	10.1289/ehp.9413
Language	English
Publisher	National Institute of Environmental Health Sciences
Publisher Date	2006-12-01
Access Restriction	Open
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Subject Keyword	biomonitoring conjugate ethylparaben metabolism methylparaben butylparaben n-propylparaben p-hydroxybenzoic acid esters urine
Content Type	Text
Resource Type	Article
Subject	Health, Toxicology and Mutagenesis Public Health, Environmental and Occupational Health