Hydrolysis Reaction Mechanism in Atrazine Metabolism and Prediction of Its Metabolites’ Toxicities

Abstract

Atrazine (ATR) is a widely used herbicide. There are several types of reactions in its metabolism. Herein, the mechanism of three paths of hydrolysis reactions in its metabolism and predictions of toxicities of its metabolites in the three paths will be presented. The calculation results by B3LYP (Becke, 3-parameter, Lee-Yang-Parr), one of the approaches in density functional theory, indicated that (1) there were three models in the three hydrolysis paths of ATR. The dissociation mechanisms of C(9/11)-N(8/10), C(4/6)-N(8/10), and C-Cl were dealkylation, deamination, and Cl substitution, respectively. (2) The energy barrier of C-Cl dissociation was lower. The dissociation was advantageous in dynamics and the primary reaction in the three hydrolysis paths. In these hydrolysis reactions, the different intermediates had different concentrations because of the impact of the reaction rate. (3) In addition, it was necessary to consider the solvent effect to investigate hydrolysis reaction. The conductor-like polarizable continuum model (CPCM) was used to simulate the hydrolysis reaction in bond length and energy barrier because of the solvent effect. Experimental or predictive results showed that atrazine and its metabolites in the three hydrolysis paths were carcinogenic.

Impact of Solute Properties and Water Matrix on Nanofiltration of Pesticides

“…Atrazine is a particular concern as it is an aromatic compound with low biodegradability rate and may concentrate in animal tissues . Atrazine is also possibly carcinogenic and related to ovary cancer , . Dimethoate is of great concern because of its potential neurotoxicity effect on human beings .…”

Atrazine Triggers Mitochondrial Dysfunction and Oxidative Stress in Quail (Coturnix C. coturnix) Cerebrum via Activating Xenobiotic-Sensing Nuclear Receptors and Modulating Cytochrome P450 Systems

“…2,5 An important finding was that ATR and its metabolites were predicted to have carcinogenicity. 6 Extensive study has revealed ATR has negative impacts on humans and animals, especially in the nervous system. 7−9 The incidence of Parkinson's disease among rural workers in ATR-exposed environments has been shown to be increased.…”

Assessment of the electronic structure and properties of trichothecene toxins using density functional theory

“…Type B trichothecenes possess a carbonyl in the R5 position and include compounds 1-10, and 29. This study also includes the type A trichothecene T-2 toxin and related compounds (11)(12)(13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28). T-2 toxin is associated with a variety of harmful effects, including alimentary toxic aleukia, and is a possible war agent [1].…”

“…These calculations describe the quantum nature of materials using an exchange-correlation functional, and have been highly successful in providing insight into structure based phenomena that are difficult to study experimentally [8,9]. Density functional studies have provided important information on toxin structures [10][11][12][13][14][15]; however, these methods have only been applied to a few trichothecene toxins. DFT studies at the B3LYP/6-31G(d,p) level of theory on the tautomers of deoxynivalenol and nivalenol gave additional structural insight into tautomer preferences and the interpretation of experimental IR and physical data [16,17].…”

“…The type B trichothecenes have natural charges of 0.54 at C8, −0.10 to −0.11 at C9, and −0.08 to −0.11 at C10, and this pattern has been associated with Michael acceptor reactions[48]. In contrast, T-2 toxin and other trichothecenes(11)(12)(13) with an ester or hydroxyl group(18)(19)(20) and 22) attached to the C8 position have charges of 0.09-0.10 at C8, 0.00 at C9, and −0.18 to −0.19 at C10. Unsubstituted trichothecenes at the C-8 position and possess the C9 C10 double bond (14-17, 21, 23-28, 31-35) have charges of −0.39 to −0.41 at C8, −0.02 to 0.03 at C9, and −0.19 to −0.25 at C10.…”