Application of general toxic effects of ionic liquids to predict toxicities of ionic liquids to Spodoptera frugiperda 9, Eisenia fetida, Caenorhabditis elegans, and Danio rerio

Modeling for the toxicity of ionic liquids (ILs) is necessary to fill data gaps for untested chemicals and to understand the relevant mechanisms at the molecular level. In order for many researchers to easily predict toxicity and/or develop some prediction model, simple method(s) based on a single parameter should be proposed. Therefore, previously our group developed a comprehensive toxicity prediction model with unified linear free-energy relationship descriptors to address the single parameter for predicting the toxicities, as follows (Cho et al., 2016b). Log 1/toxicity in the unit of mM = (2.254 E-c - 2.545 S-c + 0.646 A(c) - 1.471 B-c + 1.650 V-c + 2.917 J(+) 0.201 E-a + 0.418 V-a + 0.131 J(-)) - 0.709. It is considered that the model can calculate the general toxicological effect of ILs in parenthesis, as it was developed on the basis of numerous toxic effects i.e., 58 toxicity testing methods and about 1600 data points. In order to check the hypothesis, the values calculated by the model were correlated with four different datasets from insect cell line (Spodoptera frugiperda 9), earthworm (Eisenia fetida), nematode (Caenorhabditis elegans), and fish (Danio rerio). The results clearly showed that the calculated values are in good agreement with each dataset. In the case of S. frugiperda 9 cells, the calculated parameters were correlated with log1/LC50 values, measured after 24 h and 48 h incubation, in R-2 of 0.67 and 0.88, respectively. The R-2 values for the earthworm, nematode, and fish were 0.88, 0.96, and 0.94 -0.95, respectively. This study confirmed that the comprehensive model can be simply and accurately used to predict toxicity of ILs. (C) 2019 Elsevier Ltd. All rights reserved.