ChEBI: Ergothioneine is a L-histidine derivative that is N(alpha),N(alpha),N(alpha)-trimethyl-L-histidine in which the hydrogen at position 2 on the imdazole ring is replaced by a mercapto group. A naturally occurring metabolite of histidine synthesized by bacteria and fungi with antioxidant properties. It is found ubiquitously in plants and animals and is present in many human foodstuffs. It has a role as an antioxidant, a fungal metabolite, a plant metabolite, a xenobiotic metabolite and a chelator. It is an amino-acid betaine, a L-histidine derivative and a sulfur-containing amino acid. It is a conjugate base of an ergothioneine(1+). It is a tautomer of an ergothioneine thione form.
