In vivo nitration mechanisms of bisphenol compounds in vegetables and risk assessment at the cellular and subcellular levels

Nitrate in water promotes the generation of toxic nitrogen-containing organic compounds through photochemical reactions, raising the question of whether excessive nitrogen fertilizer use may also stimulate the formation of such compounds in plants. Bisphenol F (BPF), as a widely detected bisphenol compound in vegetables, was investigated for its nitrogenous derivatives' formation and potential toxicity within plant subcellular structures. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS), six BPF-derived nitrogen-containing compounds were identified. ECOSAR software analysis and mouse hepatocyte experiments confirmed that these derivatives exhibit greater toxicity than BPF. Transcriptomic analysis and validation experiments with inhibitors revealed that, compared to mitochondria and the cytoplasm, chloroplasts possess unique conditions for the generation of nitric oxide radical (NO•) and nitrogen dioxide radical (NO 2 •), which promotes the formation of BPF-derived nitrogen-containing compounds. This study highlights the need for rational nitrogen fertilizer use and monitoring of bisphenol compounds in vegetables.