Theoretical Elucidation of Structure-Antioxidant Activity Relationships for Thiazolidinone Derivatives

Thiazolidinone Derivatives (TD) are a novel class of calcium ion (Ca2+) antagonists possessing both Ca2+ overload inhibition and antioxidant activity. The free radical scavenging activity of TD play a key role in its cardioprotective processes. To elucidate the structure-antioxidant activity relationships (SAAR) for TD, a series of phenolic analogues of TD were constructed by adding various substituents to phenol step by step. And the theoretical parameter characterizing the free radical scavenging activity, O–H bond dissociation energy (BDE), was calculated for these phenols by quantum chemical method AM1/B3LYP/6-31G**. Thus, the contribution of each substituent to the O–H BDE was obtained. As a result, not only the SAAR for TD was explained, but also the understanding on TD's antioxidative mechanism was deepened.