Abstract

Ergothioneine (ERG) has long been recognized as a potent and stable antioxidant. In nature, ERG is synthesized only in fungi and mycobacteria, not in plants. The lifecycle of Gastrodia elata, an achlorophyllous orchid plant, is completely dependent on the presence of symbiotic fungi, particularly Armillaria mellea. In this study, we report for the first time that G. elata accumulated ERG whose levels were correlated with the concentrations of ERG in A. mellea. The contents of ERG in G. elata were significantly higher in actively developing tissues, such as seed capsules and newly growing corms, than in mature rhizomes. The ERG levels in rhizomes were significantly correlated with antioxidant capacities and were quantitatively comparable to the previously established major pharmacological components in G. elata. These results indicated that ERG is a newly found functional substance in G. elata, which may be responsible for the beneficial health effects of G. elata on various human diseases.

Key words: Gastrodia elata, Armillaria mellea, ergothioneine, antioxidant.