An NMR-based metabonomic investigation of the toxic effects of 3-trifluoromethyl-aniline on the earthworm Eisenia veneta

H-1 NMR spectra of earthworms Eisenia veneta treated with 3-trifluoromethyl-aniline in a 72-h contact filter paper test have been analysed using pattern recognition techniques to determine the biochemical response. Various strategies for data reduction of the metabolite profile, and illustration by principal components analysis are applied and discussed. The use of mean principal components plots in simplifying group data representation and highlighting the dose-response function is demonstrated. Hierarchical cluster analysis, and cluster significance analysis of the principal components were also used to examine the relative distribution of dose groups. Identification and assignment of metabolite responses to toxicity were found via correlation coefficient-shift plots. As measured by the correlation coefficients alanine was the most significant metabolite, but increased levels of other amino acids such as glycine and asparagine were also observed. Further, elevated levels of glucose, and the citric acid cycle intermediates citrate and succinate were noted as potential biomarkers of toxicity. This work provides a basis for examining the biochemical response of invertebrates to toxins. This should provide a framework to examine toxicity effects of other halogenated aromatic pollutants to earthworms used as environmental monitors.