Computational analysis of peroxyl radical scavenging capacity of coumestrol: insights into kinetics and reaction mechanisms

Abstract

AbstractCoumestrol (COM) is a phytoestrogen from the coumestan family that occurs naturally in various foods such as clover, soybeans, alfalfa sprouts, and legumes. Besides its antiestrogenic activity, COM exerts various biological activities, including anticancer, antioxidant, and α‐glucosidase inhibitory. In terms of antioxidant activity, COM has shown an excellent profile according to experimental studies; however, its mechanism of action has not been successfully determined thus far. In this contribution, we evaluated the kinetics and mechanism of the peroxyl radical (ROO•) scavenging activity of COM using quantum chemistry methods. It has been shown that the environment and the nature of the ROO• radical play a determining role in the antioxidant activity of COM. In lipid media, COM exhibits moderate ROO• scavenging activity via the formal hydrogen transfer (FHT) mechanism regardless of the nature of the ROO• radical. However, in polar environments, its activity becomes more important as the reactivity of the ROO• radical increases. Under these conditions, the single electron transfer (SET) mechanism becomes dominant or even exclusive.