| Parathyroid pesticides possess high-efficiency, low toxicity and easy degradability, so they have been widely used in our environment. But some negative issues have followed and caused the people’s attention. This paper summarized the development and negative effects of parathyroid pesticides with the widespread application on different ecological environments and living creatures.In the study of the influence of organic matter on the environment, quantitative structure-property/activity relationship (QSAR) has been an important auxiliary tool. So this paper reviewed the development and its vital role of QSAR. In QSAR studies, a quantitative relationship was established between the target enzyme activity and the chemical structure to analyze the inhibition mechanism. Target enzyme could play a role of orientation to shorten the cycle of developing new pesticides. Acetylcholinesterase (AChE) was chosen in the experiment according to reviewing the researches on the inhibitory effects of parathyroid pesticides on enzyme activity, including different enzymes such as ATP enzyme, AChE, antioxidant enzymes, glutathione peroxidase, and glutathione shift enzyme and so on.Organic solvent would bring into effect on the activity of AChE in the experiment. In order to select an appropriate organic solvent to reduce the effect on the results of the experiment, according to the literature, the inhibitory effects on enzyme activity of three popular water miscible organic solvents-dimethyl sulfoxide, acetone and anhydrous alcohol were tested in the pretest on enzyme activity. This paper selected anhydrous alcohol as an organic solvent in the experiment according to the result.The inhibition rates of 12 typical pyrethroid pesticides on the AChE activity were determined in this paper. Choosing IC10 as the dependent variable and molecular structure of pyrethroid pesticides as the independent variable, QSAR models were set up by statistical software to analyze inhibition mechanism in the article.A quantitative analysis model was established between the IC10 and molecular structure parameters using the linear multivariate regression analysis method: lgIC10= 3.765-0.403 (GGI3)-0.051 (lgP), r2=0.859. Linear fitting coefficient of the predictive value and the experimental value of LgIC10 was 0.859. A quantitative analysis model was established using the optimum subset regression analysis method: lgIC10=(2.842+-0.157)-(0.017+-0.009)(MWC05)+(5.563+-0.958)(R7v+)+(0.289+-0.047) DE, r2=0.961. Linear fitting coefficient of the predictive value and the experimental value of LgIC10 was 0.961. The models explained that inhibitory effects of pesticides on AChE were decided by the molecular space structure, electrical property and hydrophobicity.We found that the inhibition of pyrethroid pesticides on enzyme activity was connected with their electrotopological state indices of atoms. And it was an important way to build QSAR models based on molecular topology index. So a quantitative analysis model was established between the IC10 and electrotopological state indices of atoms using the linear multivariate regression analysis method: IgIC10=4.268-0.018E4-0.006E16-0.084E18, r2=0.900. Linear fitting coefficient of the predictive value and the experimental value of IgIC10 was 0.900. A quantitative analysis model was established using the optimum subset regression analysis method: IgIC10= (2.824+-0.141)-(0.017+-0.004)E4-(0.007+-0.009)E5-(0.005+-0.001)E16,r2=0.841. Linear fitting coefficient of the predictive value and the experimental value of LgIC10 was 0.842.It showed that the eletrophilic ability of pyrethroid pesticides was likely one of important factors to determine the AChE activity.Environmental conditions in vitro for determination of the inhibition of pyrethroid pesticides on AChE activity were different from that of internal environment. So QSAR models were established between the acute toxicity Half-lethal dose (LD50) and molecular structure parameters to explore the toxicity of pyrethroid pesticides for body and mammals’. Acute toxicity test was effective in toxicological analysis and the LD50 could exactly explain the biological toxicity of the pesticides and the influence on the environment. Models were as follows:1. QSAR established on the linear multivariate regression analysis method: lgLD50=9.089-0.153(RDF060e)-1.291RDF020p+0.059 RDF065m-0.1611gP, r2=0.982. Linear fitting coefficient of the predictive value and the experimental value of lgLD50 was 0.982. A model was established on the optimum subset regression analysis method: lgLD50=(7.166+-0.236)-(1.130+-0.097)DE-(0.138+-0.005)(RDF060e)-(1.606+-0.082)(RDF020p), r2=0.993. Linear fitting coefficient of the predictive value and the experimental value of lgLD50 was 0.993. The models explained that toxicity of the pesticides on rats was relevant with hydrophobicity and electronic properties in a particular direction.2. QSAR based on the electrotopological state indices was established on the linear multivariate regression analysis method: lgLD5o=0.932+0.074E4+0.061E10, r2=0.784.Linear fitting coefficient of the predictive value and the experimental value of lgLD50 was 0.784. A model was established on the optimum subset regression analysis method: lgLD50=-(12.480+-3.097)-(0.366+-0.051)E9-(0.122+-0.020)E12+(0.908+-0.179)E18, 0.903. Linear fitting coefficient of the predictive value and the experimental value of lgLD50 was 0.903. The models explained that toxicity of the pesticides on rats was relevant with the amounts and types of substituent. And it was also affected by ester group.The models above showed that toxicological mechanism of pyrethroid pesticides were relevant with the groups of electron-withdrawing, such as fluorine atoms, chlorine atoms, and ester group, etc. The molecular electrical properties and hydrophobicity played the key role on toxicological mechanism for the living creature of pyrethroid pesticides. Compared with rat, the inhibition mechanism of pyrethroid pesticides on AChE is not exactly samely by limited in vitro conditions.Hydrophobicity could not only affect toxicological properties of pyrethroid pesticides, but also play a great role in the research of the compounds nature. Two simpler and more feasible QSAR models were established to predict the lgP through the electrical topology configuration index based on the previous studies. The model on the linear multivariate regression analysis method:lgP=2.187+0.120 E14-0.306 E2+0.152 E5.The model on the optimum subset regression analysis method: lgP=(2.171+-0.494)-(0.308+-0.066)E2+(0.151+-0.054)E5+(0.121+-0.023)E,4.Two models: r2=0.936. Linear fitting coefficient of the predictive value and the experimental value of lgP was 0.937. The model showed that hydrogens were replaced by other substituent groups include hydroxyl would change the molecular hydrophobicity, furthermore, change the activity and toxicity. |
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