5,727 research outputs found

    Parabens as Urinary Biomarkers of Exposure in Humans

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    BACKGROUND: Parabens 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. OBJECTIVES: Assessing 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. RESULTS: We 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. CONCLUSIONS: The 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

    Parabens: Evidence of Estrogenicity and Endocrine Disruption Bibliography

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    Bibliography on the estrogenicity of parabensBibliography on estrogenicity and endocrine disruption of parabens. Includes references on the level of parabens in human breast tumors, potential for exposure to parabens, estrogenicity of parabens, and evidence of adverse effects on male reproduction.New York State Department of Health and Department of Environmental Conservatio

    Exploring Novel Environmental Link to Obesity: Role of Parabens in Adipogenesis \u3ci\u3ein vitro\u3c/i\u3e and \u3ci\u3ein vivo\u3c/i\u3e

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    Parabens are a group of alkyl esters of p-hydroxybenzoic acid that include methylparaben, ethylparaben, propylparaben, butylparaben, and benzylparaben. Paraben esters and their salts are widely used as preservatives in cosmetics, toiletries, food, and pharmaceuticals. Humans are exposed to parabens through the use of such products from dermal contact, ingestion, and inhalation. The extent of the exposure is reflected by the frequent detection of these compounds in urine samples in the general population. Moreover, parabens have been detected in human serum, milk, placental tissues and breast tumor tissues. Parabens have been shown to preserve estrogenic/antiandrogenic effects, and can activate peroxisome proliferator-activated receptors. Therefore, they are considered endocrine disrupting chemicals (EDC). Here, the effects of parabens on adipogenesis in vitro and in vivo were investigated. We report that (1) parabens promote adipogenesis (or adipocyte differentiation) in murine 3T3-L1 cells through activation of nuclear receptor peroxisome proliferator-activated receptor γ and glucocorticoid receptor; (2) the adipogenic potency of parabens is increased with increasing length of the linear alkyl chain in the following potency ranking order: methyl- \u3c ethyl- \u3c propyl- \u3c butylparaben; (3) parabens, butyl- and benzylparaben in particular, also promote adipose conversion of human adipose–derived multipotent stromal cells; (4) oral feeding of parabens in C57B6/J mice increase adiposity with altered metabolic biomarkers; and (5) exposure to parabens enhances adipocyte differentiation, but suppresses osteocyte and chondrocyte differentiation from a multipotent stem cell line. The results suggest that parabens may contribute to adipogenesis, through enhancing differentiation of predetermined preadipocytes, as well as through modulating the multipotent stem cells towards adipose lineage

    Environ Health Perspect

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    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

    QuEChERS and C18 as solid phase extraction sorbent - ultra-high performance liquid chromatography -ultraviolet-visible method for determination of parabens in cosmetics products

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    Concerns are growing about human exposure to endocrine-disrupting chemicals (EDCs), especially during the preadolescent development stage. Parabens are prevalent EDCs widely used as additives in cosmetics. So, the determination of parabens in such products is important. In this study, we developed a reliable and sensitive method to determine simultaneously nine common parabens (methylparaben, ethylparaben, phenylparaben, benzylparaben, penthylparaben, and two groups of isomeric compounds include propylparaben, isopropyl paraben, and butylparaben, isobutylparaben) in cosmetics products. The QuEChERS and solid-phase extraction techniques are used for extraction parabens from non-surfactant cosmetics (perfume, mouth wash solution) and surfactant cosmetics (shampoo, cream, gel), respectively and quantified by using ultra-performance liquid chromatography coupled with the ultraviolet-visible detector. All nine compounds showed good linearity with regression coefficients predominantly above 0.990. The LOD and LOQ of parabens were 0.07 µg/mL; 0.2 µg/mL, respectively. The recoveries ranged from 80 to 110% with the relative standard deviations below 8%. The developed method was successfully applied to determine parabens in various commercial cosmetic products from a local supermarket and the total parabens concentrations are in a wide-ranged from 2.0 to 1270 mg/kg

    Environmental contaminants exposure and preterm birth: a systematic review

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    Preterm birth is an obstetric condition associated with a high risk of infant mortality and morbidities in both the neonatal period and later in life, which has also a significant public health impact because it carries an important societal economic burden. As in many cases the etiology is unknown, it is important to identify environmental factors that may be involved in the occurrence of this condition. In this review, we report all the studies published in PubMed and Scopus databases from January 1992 to January 2019, accessible as full-text articles, written in English, including clinical studies, original studies, and reviews. We excluded articles not written in English, duplicates, considering inappropriate populations and/or exposures or irrelevant outcomes and patients with known risk factors for preterm birth (PTB). The aim of this article is to identify and summarize the studies that examine environmental toxicants exposure associated with preterm birth. This knowledge will strengthen the possibility to develop strategies to reduce the exposure to these toxicants and apply clinical measures for preterm birth prevention

    Ecotoxicity variation through parabens degradation by single and catalytic ozonation using volcanic rock

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    Parabens are widely used as antimicrobial and preservative ingredients in pharmaceutical and personal care products. Nevertheless, these compounds have been increasingly seen as emerging contaminants that can be toxic to a wide range of species. In this study, the toxic effect of a mixture of parabens (10 mg/L of each paraben: methyl-, ethyl-, propyl-, benzyl- and butylparaben) and its degradation products through single and catalytic ozonation (using volcanic rock as low-cost catalyst) was investigated over several non-target species: cladocerans, microalgae, clams, macrophytes and cress. The analysis of the toxicity of parabens mixture is relevant since usually these compounds are used as blends rather than individually. While parabens were totally removed both by single and catalytic ozonation the toxicity of the samples resulting from both treatments was generally high. This toxicity was still compared to the one obtained for several dilutions of the initial parabens mixture and it was concluded that the by-products formed are more toxic than the most diluted parabens mixture sample (0.625 mg/L). While catalytic ozonation allows reducing the amount of ozone (about 3-fold) required for total removal of parabens, the resulting treated solution was more toxic than the sample taken at the endpoint of the single ozonation treatment. This suggests that the highest amount of ozone used for single ozonation allowed the elimination of toxic by-products such as hydroquinone and 1,4-benzoquinone. Still, the effect of by-products and parabens interaction depends on the species analyzed due to their different tolerances to potentially toxic products.publishe
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