2-tert-Butyl-1,4-benzoquinone eliminated by amino acids: Reaction kinetics, mechanism, and potential cytotoxicity assessment of the adducts

Lys and Arg showed markedly higher TBBQ-eliminating and adduct-forming capacities. • Adducts were likely formed via a 1,4-addition and subsequent oxidation. • The elimination products of Lys-TBBQ-1 and Arg-TBBQ were verified in fried tofu. • The adducts displayed much lower cytotoxicity than TBBQ in Caco-2 cells. 2- tert -Butyl-1,4-benzoquinone (TBBQ), as a potential threat to food safety, is believed to be eliminated by amino acids. This study investigated the potential reaction mechanism between TBBQ and amino acids, and evaluated the cytotoxicity of the l -lysine-TBBQ and L-arginine-TBBQ adducts. The results indicated that the rates of TBBQ elimination and adduct formation would be promoted under alkaline conditions, and with the increase of amino acid concentrations, temperatures. Meanwhile, l -lysine and L-arginine exhibited significantly higher TBBQ-eliminating and adduct-forming capacities. Structural characterization of the l -lysine-TBBQ and L-arginine-TBBQ adducts confirmed 1,4-addition as the primary reaction pathway, validated in real food systems. Furthermore, the cytotoxicity toward Caco-2 cells was reduced with approximately 100% cell viability under 100 μM  l -lysine-TBBQ and L-arginine-TBBQ adducts, probably originating from the dramatic decrease in reactive oxygen species production and apoptosis. These findings provided the theoretical support for assessing dietary risk and developing detoxification strategies for TBBQ.