Triclosan: environmental exposure, toxicity and mechanisms of action. J Appl Toxicol

Department of Biological Sciences, Alberta Water and Environmental Science Bldg, 4401 University Dr. W., University of Lethbridge, Lethbridge, Alberta, Canada.
Journal of Applied Toxicology (Impact Factor: 2.98). 05/2011; 31(4):285-311. DOI: 10.1002/jat.1660
Source: PubMed


Triclosan [5-chloro-2-(2,4-dichlorophenoxy)phenol; TCS] is a broad spectrum antibacterial agent used in personal care, veterinary, industrial and household products. TCS is commonly detected in aquatic ecosystems, as it is only partially removed during the wastewater treatment process. Sorption, biodegradation and photolytic degradation mitigate the availability of TCS to aquatic biota; however the by-products such as methyltriclosan and other chlorinated phenols may be more resistant to degradation and have higher toxicity than the parent compound. The continuous exposure of aquatic organisms to TCS, coupled with its bioaccumulation potential, have led to detectable levels of the antimicrobial in a number of aquatic species. TCS has been also detected in breast milk, urine and plasma, with levels of TCS in the blood correlating with consumer use patterns of the antimicrobial. Mammalian systemic toxicity studies indicate that TCS is neither acutely toxic, mutagenic, carcinogenic, nor a developmental toxicant. Recently, however, concern has been raised over TCS's potential for endocrine disruption, as the antimicrobial has been shown to disrupt thyroid hormone homeostasis and possibly the reproductive axis. Moreover, there is strong evidence that aquatic species such as algae, invertebrates and certain types of fish are much more sensitive to TCS than mammals. TCS is highly toxic to algae and exerts reproductive and developmental effects in some fish. The potential for endocrine disruption and antibiotic cross-resistance highlights the importance of the judicious use of TCS, whereby the use of TCS should be limited to applications where it has been shown to be effective.

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    • "The other interesting thing about triclosan is that like sodium fluoride, triclosan in toothpaste and other dental care products can reduce gum disease, especially in individuals that are prone to gum disease (Dann and Hontela 2011). Thus, for people that have a lot of gum problems, using toothpastes and other dental products that contain triclosan can have a definite benefit. "
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    DESCRIPTION: A summary of interesting information that is pertinent to the student assignment to evaluate contaminants in products in their own households.
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    • "Well-known local antibacterial agent Triclosan (1) has been reported to be a specific InhA inhibitor (Levy et al., 1999). Unfortunately, Triclosan has the disadvantage such as higher lipophilicity and moderate MIC (12.5 lg/ml) (Dann and Hontela, 2011). Hence major attention has been put forward to develop a druggable Triclosan analogue with improved antitubercular activity. "
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    ABSTRACT: Novel Triclosan mimic diphenyl ether derivatives 4a-k was designed and synthesized with lipophilicity considerably lesser than that of Triclosan. The binding mode of the compounds at the active site of enoyl-ACP reductase was analysed using docking method. The syntheses were carried out with one-pot reductive amination reaction and were characterized by spectral techniques. The synthesized compounds were evaluated for their in vitro antitubercular activity against Mycobacterium tuberculosis H37Rv strain by Microplate Alamar Blue assay. Compounds 4h and 4j were the most active compounds with MIC equal to 25μg/mL against Mycobacterium tuberculosis H37Rv strain. All compounds were also examined for their cytotoxic potential against VERO and HepG2 cell lines and were safe even at 300μg/mL. Log P of all the synthesized compounds was evaluated by RPHPLC and was significantly lesser than Triclosan.
    Arabian Journal of Chemistry 09/2015; DOI:10.1016/j.arabjc.2015.09.003 · 3.73 Impact Factor
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    • "Moreover, their effects on zebrafish embryos were already studied within our group (Domingues et al., 2013, 2010; Oliveira et al., 2009). TCS is a common bactericide used in oral care products, acrylic products, plastic materials and cosmetics (Dann and Hontela, 2011) and has been frequently found in the environment. Singer et al. (2002) observed concentrations ranging from 42 to 213 ng L À 1 downstream of several sewage treatment plants in Switzerland. "
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    ABSTRACT: At ecosystems level, environmental parameters such as temperature, pH, dissolved oxygen concentration and intensity of UV radiation (UVR) have an important role on the efficiency of organisms' physiological and behavioral performances and consequently on the capacity of response to contaminants. Insignificant alterations of these parameters may compromise this response. In addition, these parameters can additionally alter chemical compounds by inducing their degradation, producing thereafter other metabolites. Understanding the combined effects of chemicals and environmental parameters is absolutely necessary for an adequate prediction of risk in aquatic environments. According to this scenario, this work aims at studying the combined toxicity of UVR and three xenobiotics: the biocide triclosan (TCS), the metal chromium (as potassium dichromate, PD) and the fungicide prochloraz (PCZ). To achieve this goal zebrafish (Danio rerio) embryos (3h post fertilization (hpf)) were exposed to several concentrations of each chemical combined with different UV intensities; mortality and eggs were recorded every 24h for the all test duration (96h). Results showed different response patterns depending on the toxicant, stress levels and duration of exposure. The combination of UVR and TCS indicated a dose ratio deviation where synergism was observed when UVR was the dominant stressor (day 2). The combination of UVR and PD presented a dose level dependency at day 3 indicating antagonism at low stress levels, changing with time where at day 4, a dose ratio deviation showed statistically that synergism occurred at higher PD concentrations. Finally, UVR combined with PCZ indicated a dose ratio at day 3 and dose level deviation at day 4 of exposure, suggesting a synergistic response when PCZ is the dominant stressor in the combination. The obtained results in this study highlighted the importance of taking into account the possible interaction of stressors and time of exposure to better predict environmental risk. Copyright © 2015 Elsevier Inc. All rights reserved.
    Ecotoxicology and Environmental Safety 07/2015; 122:145-152. DOI:10.1016/j.ecoenv.2015.07.021 · 2.76 Impact Factor
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