Thursday, March 13, 2014

More information about Triclosan

Today I spoke about Triclosan in class, however due to time constraints, I was unable to really cite any sources. A few people seemed interested in finding out more information, so I wrote up a little paragraph summarizing some of the main points, and provided links to my sources.

I happen to think that it's a good looking molecule 
First registered as a pesticide in 1969 (1), Triclosan is widely used as an antimicrobial compound, and is present in everything from hand soap to surgical instruments. Triclosan's main method of action involves inhibiting bacterial fatty acid synthesis at the enoyl-acyl carrier protein reductase (FabI) step (2). Humans lack this enzyme, and the EPA concluded that Triclosan would have no effect on people. A 2006 study (3) demonstrated that Triclosan acts as an endocrine disruptor in frogs, is known to enter the bloodstream of humans through the skin (4), and was found in 75% of peoples urine samples in a 2010 (5) study with concentrations ranging from 2.4-3790 ug/L. More recently, in a August 2012 UC Davis study, Triclosan was found to depolarize L-type calcium channels and reduce cardiac output in mice (6).  California ocean water contains Triclosan in concentrations approaching 732 ppt (7), the highest levels in the nation.
1. Triclosan Facts Pesticides: Reregistration. US Environmental Protection Agency. [Online] http://www.epa.gov/oppsrrd1/REDs/factsheets/triclosan_fs.htm.
2. Mechanism of Triclosan Inhibition of Bacterial Fatty Acid Synthesis. [Online] http://www.jbc.org/content/274/16/11110.
3. The bactericidal agent triclosan modulates thyroid hormone-associated gene expression and disrupts postembryonic anuran development. Science Direct. [Online] http://www.sciencedirect.com/science/article/pii/S0166445X06003407.
4. Moss T, Howes D, Williams FM. Percutaneous penetration and dermal metabolism of triclosan (2,4, 4'-trichloro-2'-hydroxydiphenyl ether). PubMed.Gov. [Online] http://www.ncbi.nlm.nih.gov/pubmed/10722890.
5. Drinking Water Contaminants of Emerging Concern Program. s.l. : Minnesota Department of Health, 2010. http://www.health.state.mn.us/divs/eh/risk/guidance/dwec/cecfy10report.pdf
6. Triclosan impairs excitation–contraction coupling and Ca2+ dynamics in striated muscle. s.l. : UC Davis, 2012. http://www.pnas.org/content/early/2012/08/08/1211314109.full.pdf+html

7. Revised Environmental Fate Science Chapter for the Triclosan. s.l. : UNITED STATES ENVIRONMENTAL PROTECTION AGENCY.
http://www.oehha.org/prop65/public_meetings/052909coms/triclosan/ciba7.pdf

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