We determined the concentration at which organic substances antagonize metamorphosis induction in the hydroid Hydractinia echinata. The substances belong to several classes, such as normal and branched alkanes, alkylbenzenes, polyaromatic hydrocarbons, alkanols, polyols, phenylcarbinols, aliphatic primary amines, diaminoalkanes, aminoalkanols, and substituted aminoethanols. For QSAR analysis we correlated the measured toxicity with the respective logP OW value. Within a substance class the dependence was almost linear, but in different classes the respective slopes were different. In two classes, aliphatic amines and polyalkanols, the toxicity did not increase with increasing logP OW values. This led us to the attempt to calculate parameters for the various structural components of the substances (e.g. the number of C-atoms and the functional groups), which when properly combined result in an estimate of the toxicity of a substance. The results obtained ®t well the measured data. The approach was also successfully applied to published toxicity data obtained with other organisms including Tetrahymena pyriformis (ciliate), Daphnia magna (crustacea), and Pimephales promelas (bony ®sh). On the basis of this approach we made predictions for toxicity values for not yet tested substances with respect to these systems.

Aiming to provide a unified picture of computed activity – quantitative structure activity relationships, the so called Köln (ESIP-ElementSpecificInfluenceParameter) model for activity and Timisoara (Spectral-SAR) formulation of QSAR were pooled in order to assess the toxicity modeling and inter-toxicity correlation maps for aquatic organisms against paradigmatic organic compounds. The Köln ESIP model for estimation of a compound toxicity is based on the experimental measurement expressing the direct action of chemicals on the organism Hydractinia echinata so that the structural influence parameters are reflected by the metamorphosis degree itself. As such, the calculation of the structural parameters is absolutely necessary for correct evaluation and interpretation of the evolution of M(easured) and the C(computed) values. On the other hand, the Timişoara Spectral-SAR analysis offers correlation models and paths for H.e. species as well as for four other different organisms with which the toxicity may be inter-changed by means of the same mechanism of action induced by certain common chemicals.

No abstract

No abstract

BackgroundNitroaromatic and chloronitroaromatic compounds have been a subject of great interest in industry and recently in medical-pharmaceutic field. 2-Chloro-4-nitro/2-chloro-5-nitrobenzoic acids and 4-nitrobenzoic acid are promising new agents for the treatment of main infectious killing diseases in the world: immunodeficiency diseases and tuberculosis.ResultsNew ethanolamine nitro/chloronitrobenzoates were synthesized and characterized by X-ray crystallography, UV–vis, FT-IR and elementary analysis techniques. The toxicity of the compounds prepared and correspondent components was evaluated using Hydractinia echinata as test system. A significant lower toxicity was observed for nitro-derivative compared with chloronitro-derivatives and individual components. Crystallographic studies, together with the chemical reactivity and stability profiles resulted from density functional theory and ab initio molecular orbital calculations, explain the particular behavior of ethanolamine 4-nitrobenzoate in biological test.ConclusionsThe experimental and theoretical data reveal the potential of these compounds to contribute to the design of new active pharmaceutical ingredients with lower toxicity.Electronic supplementary materialThe online version of this article (10.1186/s13065-017-0346-5) contains supplementary material, which is available to authorized users.