Theorical study of the antioxidant capacity of garlic compounds against different oxygen reactive species

MATÍAS F. ANDRADA; ESTEBAN G. VEGA HISSI; JUAN C. GARRO MARTINEZ; MARIO R. ESTRADA

Carlos Paz

Congreso; 13th Latin American Conference on Physical Organic Chemistry (CLAFQO-13); 2015

CLAFQO - UNC

From the experimental point of view, the allyl methyl disulfide (AMDS), the allyl methyl sulfide (AMS) and the diallyl disulfide (DADS), among other sulfur compounds present in garlic extract, have proven antioxidant capacity against reactive oxygen species (ROS).Although these compounds, in aqueous medium, have the ability to reduce reactive oxygen species such as hydrogen peroxide (H2O2), hydroxyl radical (? OH), superoxide anion (O2 ? -), few information is available regarding the reaction mechanisms of their physiological antioxidants effects.Our research group has been working on the reaction mechanisms of the sulfur compounds against hydrogen peroxide from both, thermodynamically and kinetically, points of view.The main objective of this work is to extend the study to several ROS, in order to compare their antioxidant capacity and possible reaction pathways. Therefore, possible reaction pathways are proposed when garlic sulfur compounds react with different ROS. The potential oxidation sites are sulfur atoms and carbon-carbon double bonds which may exist in these compounds.According to the objective of the work, frequency calculations on AMDS, MAS, DADS, hydrogen peroxide, hydroxyl radical and superoxide anion were performed in gas phase and taking into account the effect of solvent (water) to obtain the thermodynamic properties.The free energies of oxidation reaction of the proposals are also obtained, allowing us to determine the thermodynamic feasibility of the same. All these calculations were carried out at the level of theory B3LYP / 6-31G + (d) with the Gaussian 03 program.In order to meet these oxidation products is important to determine the possible paths that the reduction reactions of all ERO, because the products generated in these reactions can be as toxic as generating species of oxidative stress.