β-Hydroxyergothioneine, a New Ergothioneine Derivative from the Mushroom Lyophyllum connatum, and Its Protective Activity against Carbon Tetrachloride-Induced Injury in Primary Culture Hepatocytes

Abstract

A new ergothioneine derivative named β-hydroxyergothioneine was isolated from the mushroom Lyophyllum connatum. Ergothioneine,N-hydroxy-N′,N′-dimethylurea, and connatin (N-hydroxy-N′,N′-dimethylcitrulline) were also isolated. All the compounds displayed the ability to scavenge free radicals, based on a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay. Structural determination, including the absolute stereochemistry of β-hydroxyergothioneine, was achieved by spectroscopic analysis and X-ray crystallography. The radical scavenging activity of β-hydroxyergothioneine was almost the same as that of ergothioneine. β-Hydroxyergothioneine showed the greatest protective activity against carbon tetrachloride-induced injury in primary culture hepatocytes.