Antioxidant properties of bucillamine: possible mode of action.

The antioxidant properties of Bucillamine (BUC), a di-thiol compound used for treatment of rheumatoid arthritis (RA) and its possible mode of action, were investigated. BUC exhibits potent antioxidant activity similar to those of trolox and ascorbic acid. It reduces the stable free radical diphenyl-2-picrylhydrazyl (DPPH) with IC(50) of 18.