ANTIOXIDATIVE POTENCY AND RADICAL SCAVENGING ACTIVITY OF SELECTED COUMARIN-HYBRIDS

In previous studies, it was found that coumarins with hydrazide moiety show good antioxidative potential, while similar coumarins with hydrazone moiety are good anticancer agents. In this paper, the antioxidative potency and radical scavenging activity of two coumarin hydrazone derivatives were investigated. For this purpose, density functional theory method M062X with 6-311G++(d,p) basis set was implemented. It was found that investigated compounds exhibit good antioxidative potency, with very similar BDE values regardless of the position involved. On the other hand, PA values show that a preferable functional group for proton loss depends on the position of the OH group. In ortho position, OH group shows lower antioxidative potency than NH group, while in the same time in para position OH group is favourable position for antioxidative activity reactions. A similar situation is obtained by investigation of radical scavenging mechanisms, with the more pronounced difference in BDE between the positions in favour of the NH group. While SPLET is the most probable mechanism which is in competition with HAT in some cases (hydroxy radical) SET-PT was found to be a non-operative mechanistic pathway.