A DFT study on the scavenging activity of curcumin toward methyl and ethyl radicals

Abstract

The curcumin is a well-known antioxidant that can scavenge free radicals efficiently. The methyl free radicals, generated by the metabolism of various genotoxic compounds such as hydrazines and peroxides, can methylate various sites in DNA. Herein, we have carried out density functional theory calculations to investigate the scavenging activity of curcumin toward the methyl and ethyl radicals through radical adduct formation (RAF), hydrogen atom transfer (HAT) and single electron transfer (SET) mechanisms. The SET mechanism is found to be highly endergonic and so not viable. Our calculations show that the curcumin can scavenge methyl radicals through both RAF and HAT mechanisms but RAF would be preferred over the HAT. Further, it is found that the curcumin can scavenge methyl radicals more efficiently as compared to ethyl radicals through RAF mechanism.