ABSTRACT
Ergothioneine is widely distributed in biological systems, particularly in red blood cells of animals. However, it's functional role in human body is not well understood. In order to investigate the biochemical effect of L-ergothioneine, its concentration changes in human blood with respect to ages in healthy individuals was first investigated. L-ergothioneine concentrations in the blood of Saudi males from western province at different stages of life were measured by the procedure of Carlsson et al., 1974. At early stages of life (1-10 years), the concentrations of LER is 1.5-2.0 mg/100 ml. It increases gradually at the age of 11-18 years where it reaches the maximum value of 3.7 mg/100 ml. Then, it declines gradually to 3.0-2.3 mg/ 100 ml during the period of 19-50 years. An increase in the level of LER (2.8 mg/100 ml) was seen at the age of 51+.