Novel Dithiocarbamic Flavanones with Antioxidant Properties—A Structure–Activity Relationship Study

The antioxidant properties of some 3-dithiocarbamic flavanones were investigated. Based on a previous study, we selected three frameworks that proved to be the most active ones. By varying the nature of the substituent at the para-position of flavanone ring <b>B</b>, a structure-activity relationship study on radical scavenging activities was performed. The influence of these substituents (H, F, Cl, Br and I) was evaluated in relation to DPPH, ABTS and FRAP. The results indicated that the presence of the halogen substituent induced better antioxidant properties than ascorbic acid and BHT. The radical scavenging activities were found to decrease in the following order: F > Cl > Br > I > H. This is correlated with the decrease in electronegativity and withdrawing inductive effect of these substituents, which make the C(2)-H bond of the benzopyran ring prone to hydrogen radical transfer.