FREE-RADICAL SCAVENGING ACTIVITY OF CURCUMINOIDS

Three natural curcuminoids (curcumin (CAS 458-37-7), demethoxycurcumin , bisdemethoxycurcumin) and acetylcurcumin were compared for their abi lity to scavenge superoxide radicals and to interact with 1,1-diphenyl -2-picryl-hydrazyl (DPPH) stable free radicals. The results showed tha t curcumin is the most potent scavenger of superoxide radicals followe d by demethoxycurcumin and bisdemethoxycurcumin. Acetylcurcumin was in active. Interaction with DPPH showed a similar activity profile. The s tudy indicates that the phenolic group is essential for the free radic al scavenging activity and presence of methoxy group further increases the activity.