1-D and 2-D NMR-based metabolomics of earthworms exposed to endosulfan and endosulfan sulfate in soil

One-dimensional (1-D) and two-dimensional (2-D) nuclear magnetic resonance (NMR)-based metabolomics was used to investigate the toxic mode of action (MOA) of endosulfan, an organochlorine pesticide, and its degradation product, endosulfan sulfate, to Eisenia fetida earthworms in soil. Three soil concentrations (0.1, 1.0 and 10.0 mg/kg) were used for both endosulfan and endosulfan sulfate. Both earthworm coelomic fluid (CF) and tissues were extracted and then analyzed using 1H and 1H–13C NMR techniques. A similar separation trajectory was observed for endosulfan and endosulfan sulfate-exposed earthworms in the mean principal component analysis (PCA) scores plot for both the earthworm CF and tissue extracts.A neurotoxic and apoptotic MOA was postulated for both endosulfan and endosulfan sulfate exposed earthworms as significant fluctuations in glutamine/GABA–glutamate cycle metabolites and spermidine were detected respectively. This study highlights the application of NMR-based metabolomics to understand molecular-level toxicity of persistent organochlorine pesticides and their degradation products directly in soil.

► NMR-based earthworm metabolomic analysis of endosulfan and endosulfan sulfate.
► The earthworm species Eisenia fetida was exposed to sub-lethal soil concentrations.
► Both coelomic fluid and tissue extracts were analyzed by 1H NMR and 1H–13C NMR.
► Similar toxicity was seen with endosulfan and endosulfan sulfate exposed earthworms.
► A neurotoxic and apoptotic mode of action was delineated for both contaminants.