The maize benzoxazinone DIMBOA reacts with glutathione and other thiols to form spirocyclic adducts

► Grass benzoxazinones such as DIMBOA readily react with thiols. ► DIMBOA reacts with glutathione to form stable spirocyclic adducts. ► Protein cysteinyl residues similarly react with DIMBOA. ► This reactivity is likely to result in toxicity on ingestion.