engleski

The role of catechol moiety in free radical scavenging by simple hydroxybenzoic acids

Numerous epidemiological studies have shown that beneficial health effects of diets rich in fruits and vegetables are due to their flavonoid content. However, low bioavailability of flavonoids suggests that their bioactivity could be associated with their colonic metabolites, present in circulation at higher concentrations. Majority of ingested flavonoids undergo colonic metabolism resulting in a common set of simpler hydroxybenzoic acids and phenols. One of their structural motifs is catechol moiety, commonly present in many natural dietary products that exert cancer chemopreventive effects. Free radical scavenging potency of several simple hydroxybenzoic acids was studied in silico employing DFT approach as implemented in Gaussian 09 package. Geometry optimizations and frequency calculations were carried out using the M06-2X/6-311++G(d, p) level of theory, in conjunction with the SMD solvation model. Two mechanisms of radical scavenging reaction were considered – double hydrogen atom transfer (dHAT) and double sequential proton loss electron transfer (dSPLET). Obtained thermodynamic results indicate that all studied hydroxybenzoic acids possess high free radical scavenging potency and are able to deactivate various radicals. Second HAT and SPLET processes have been estimated to be less energy demanding than the first ones.

free radical scavenging ; DFT ; dHAT ; dSPLET

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