4935-93-7Relevant articles and documents
Inhibitory effects of natural organic matter on methyltriclosan photolysis kinetics
Liu, Wei,Jin, Lide,Chen, Kai,Li, Yanyan,Dahlgren, Randy A.,Ma, Meiping,Wang, Xuedong
, p. 21265 - 21271 (2018)
This study evaluated the effects and related mechanisms of natural organic matter (NOM) on the photolysis of methyltriclosan (MTCS), a metabolite of triclosan. Addition of two representative NOM isolates, Pony Lake fulvic acid (PLFA-microbial origin) and Suwannee River fulvic acid (SRFA-terrestrial origin), significantly inhibited the direct photolytic rate of MTCS by ～70%. The MTCS photolytic rate in the presence of PLFA was greater than for SRFA. NOM not only suppressed photolysis by light-shielding, but also produced ROS to oxidatively degrade MTCS and/or triplet NOM (3NOM?) to sensitize degradation. The dual effects of light-screening and photo-sensitization led to an overall decrease in photolysis of MTCS with a positive concentration-dependence. Upon addition of NOM, EPR documented the occurrence of 1O2 and OH in the photolytic process, and the bimolecular k value for the reaction of 1O2 with MTCS was 1.86 × 106 M-1 s-1. ROS-quenching experiments indicated that the contribution of OH (19.1-29.5%) to indirect photolysis of MTCS was lower than for 1O2 (38.3-58.7%). Experiments with D2O further demonstrated that 1O2 participated in MTCS photodegradation. Moreover, the addition of sorbic acid and O2 gas to the reaction confirmed the participation of 3NOM? as a key reactant in the photochemical transformation of MTCS. This is the first comprehensive analysis of NOM effects on the indirect photolysis of MTCS, which provides new insights for understanding the environmental fate of MTCS in natural environments.
Novel diaryl ureas with efficacy in a mouse model of malaria
Anderson, John W.,Sarantakis, Dimitri,Terpinski, Jacek,Santha Kumar,Tsai, Han-Chun,Kuo, MacK,Ager, Arba L.,Jacobs Jr., William R.,Schiehser, Guy A.,Ekins, Sean,Sacchettini, James C.,Jacobus, David P.,Fidock, David A.,Freundlich, Joel S.
, p. 1022 - 1025 (2013/03/13)
Exploration of triclosan analogs has led to novel diaryl ureas with significant potency against in vitro cultures of drug-resistant and drug-sensitive strains of the human malaria parasite Plasmodium falciparum. Compound 18 demonstrated EC50 values of 37 and 55 nM versus in vitro cultured parasite strains and promising in vivo efficacy in a Plasmodium berghei antimalarial mouse model, with >50% survival at day 31 post-treatment when administered subcutaneously at 256 mg/kg. This series of compounds provides a chemical scaffold of novel architecture, as validated by cheminformatics analysis, to pursue antimalarial drug discovery efforts.
Occurrence of Methyl Triclosan, a Transformation Product of the Bactericide Triclosan, in Fish from Various Lakes in Switzerland
Balmer, Marianne E.,Poiger, Thomas,Droz, Christian,Romanin, Kathrin,Bergqvist, Per-Anders,Mueller, Markus D.,Buser, Hans-Rudolf
, p. 390 - 395 (2007/10/03)
The bactericide triclosan and methyl triclosan, an environmental transformation product thereof, have been previously detected in lakes and a river in Switzerland. Both compounds are emitted via wastewater treatment plants (WWTPs), with methyl triclosan probably being formed by biological methylation. Passive sampling with semi-permeable membrane devices (SPMDs) showed the presence of methyl triclosan in some lakes, suggesting some potential for bioaccumulation of the compound. In this study, we report the presence of methyl triclosan in fish (white fish, coregonus sp.; roach, rutilus rutilus) from various lakes in Switzerland receiving inputs from WWTPs. Identification of the compound was based on mass spectral (MS) evidence including MS/MS data. The concentrations of methyl triclosan in the fish were up to 35 ng g-1 on a wet weight basis and up to 365 ng g -1 on a lipid basis with concentrations in a relatively narrow range for fish from the same lake (Thunersee, 4-6 ng g-1 Zuerichsee, 32-62 ng g-1; Pfaeffikersee, 43-56 ng g-1; Greifensee, 165-365 ng g-1, lipid basis). No methyl triclosan (-1, lipid basis) was detected in fish (lake trout, salmo trutta) from a remote lake in Sweden (Haebberstjaernen) and in fish (roach) from a small lake in Switzerland with no input from WWTPs (Huettnersee, -1, lipid basis). The concentrations of methyl triclosan in fish correlated (r2 = 0.85) with the ratio of population in the watershed to water throughflow of the lakes (P/Q ratio), which is considered to be a measure for the domestic burden from WWTPs to a lake. Passive sampling with SPMDs confirmed the presence of methyl triclosan in lakes and a river (Zuerichsee and Greifensee; Limmat) but not in a remote mountain lake (Joerisee) and in Huettnersee. The bioconcentration factor (BCF) of methyl triclosan estimated from the fish data and SPMD-derived water concentrations was in the order of 1-2.6 × 105 (lipid basis) and thus in the range of other persistent organic pollutants. SPMDs were found to be reliable for monitoring low concentrations of methyl triclosan in surface water. Methyl triclosan appears to be a suitable marker for WWTP-derived lipophilic contaminants in the aquatic environment and fish.
