Gentisate, a salicylate metabolite with antioxidant properties.

Concentrations of gentisate found in plasma and synovial fluid were in excess of concentrations required to exert an antioxidant effect in vitro. Studies of diphenol/aminophenols suggested that an ortho or para configuration of functional groups was required for this in vitro antioxidant activity. Animal studies indicated some correlations between in vitro activity and pharmacology of these agents.