Metabolomics reveals formonetin mitigates neurotoxicity of CL-20 on neuron cells

2,4,6,8,10, 12-hexanitro-2,4,6,8,10, 12-hexazepane (CL-20) is considered a persistent organic pollutant. In order to study the related effects of CL-20 on human neurotoxicity and its mechanism, SK-N-AS cells were treated with different concentrations of CL-20 for 72 h, cell proliferation test was conducted, and then cultured with DMEM medium and 0.5 mg·mL^-1 CL-20 solution for 72 h, respectively, and samples were taken for metabolomics analysis. The cytotoxicity test showed that CL-20 had certain toxic effect on SK-N-AS cells. Non-targeted metabolomics analysis revealed that 120 differentiated metabolites were identified in CL-20-treated SK-N-AS cells, of which 90 metabolites were significantly reduced. KEGG enrichment analysis showed that the main pathways included metabolic pathways, ABC transporters, amino acid biosynthesis, mineral absorption and so on. Formonetin, L-phenylalanine, L-proline and glycine were significantly reduced, and were identified as candidate metabolites by ROC analysis, which was speculated to have a protective effect on cells. Verification experiments showed that only formononetin had a protective effect on cells and could significantly inhibit the toxic effect of CL-20 on cells, may have neuroprotective potential.