QSAR Study Of Toxic Effects And Benzophenone UV Sunscreen

Benzophenones (abbreviated as BPs) are widely used in UV filters, fragrance enhancers, and additives for plastics. UV filters’s environmental and health risk effect get people to pay attention with the use of UV sunscreen products. In this study, three toxicity tests, including SOS/umu genotoxicity, acute toxicity of luminescent bacteria growth inhibition and daphnia swimming immobilization, were exploited to evaluate the toxicity effects of fourteen benzophenone UV-filters.2D-QSAR,3D-QSAR and Autodock studies were exploited. The relationship between toxicity effects and molecular structure was analyzed by QSAR and Autodock calculation in order to explore the different influence of molecular structure to various toxicity and presume the toxic mechanism. Based on the toxicity data in this study, using evaluation factor (Assessment factor, AF) method, we derived the PNEC values of17kinds of UV filters compounds, providing support for the decision makers in terms of ecological risk control for toxic pollutants.For SOS/umu genotoxicity, an index lowest positive effect concentration (LPEC), defined as the corresponding concentration when the induction ratio (77?) reached2on its dose-response curve, was determined.The results of the three toxicity effects demonstrated that the LPECs for14of BPs ranged from81.97to>1000mg/L for SOS/umu genotoxicity effects, the EC50for14of BPs ranged from17.67mg/L to243.82mg/L for acute toxicity effects of luminescent bacteria growth inhibition, the EC50for14of BPs ranged from0.42mg/L to66.78mg/L for acute toxicity effects of daphnia swimming immobilization. The results of2D-QSAR analysis demonstrated that genotoxicity effects was associated with HDon_O (number of hydrogen atom donor), but acute toxicity effects was associated with hydrophilicity. For3D-QSAR analysis genotoxicity and acute toxicity on luminescent bacteria were associated with HDon_O. The results of the Autodock analysis for acute toxicity effects on luminescent bacteria demonstrated t-dG of the highest and lowest toxicity effects compound are corresponding to lowest and highest-dG respectively. For PNEC calculation, the lowest PNEC value is BP8(2,4,4’-Trihydroxyl-BP),1.7×10-5mg/L. the highest PNEC value is BP11(2-Hydroxyl-4-methoxyl-BP),6.2x10-2mg/L, Analyse the above results, we can draw the following conclusions:(1)Acute toxicity effects on daphnia was the most significant by testing three toxicity effects.(2)Hydroxy number and position ignificantly influenced toxicity, for the umu genotoxicity effects and acute toxicity effects on luminescent bacteria, the toxicity enhanced as the number of hydroxy groups on benzene rings. For three toxicity effects, the toxicity increased as the order of2-<3-<4-hydroxyl-BP. Compound with the same the same amount of hydroxy groups, compounds with hydroxy groups locating on two benzene rings exhibit weaker toxicity than those on one benzene ring.(3)Successfully establish2D-QSAR and3D-QSAR model of describing relations between molecular structure and the toxicity effect. Model had clear structure descriptors and fitted well the test results of toxicity. The result had important significance for the toxicity prediction with such structure compounds.(4)For Autodock analysisn of acute toxicity on luminescent bacteria, the-dG calculated was corresponding to toxicity.(5)It was found that the PNEC values of BP7(2,4-Dihydroxy-BP) and BP8(2,4,4’-Trihydroxyl-BP)were low by the calculation of PNEC, but they have been detected in the environment and have certain environmental risk, the result should cause concern. This results provide scientific basis for ecological protection and management.