Theoretical study of the elimination reaction of hydrogen peroxide by Allyl Methyl Sulfide and Diallyl Methyl sulfide, two garlic compounds

DÍAZ, MARIO G.; ESTEBAN G. VEGA-HISSI; ANDRADA MATIAS; GARRO MARTINEZ, JUAN C.

San Luis

Congreso; XLVIII Reunión Anual de la Sociedad Argentina de Biofísica; 2019

Universidad Nacional de San Luis

The organosulfide compounds are organic species that contain one or more sulfur atoms in its structure. The garlic (allium sativum) have a large number of organosulfide compounds that show different properties. There are evidence of the antiviral, antibacterial, and antiparasitic activity of these compounds. In addition, these compounds decrease of cholesterol levels, inhibits platelet aggregation and tumor growth. Among them are the Allyl Methyl Sulfure (AMS) and Diallyl Mehtyl Sulfure (DMS) that show a special interest as antioxidant agents. The current investigations on antioxidant species that prevent the oxidative stress, particularly are centered on the reduction the free radicals (ROS) that can cause biological damage as anion superoxide, the hydroxyl radical and the hydrogen peroxide.In this work, we carried out theoretical quantum studies of the thermodynamic and kinetics aspect of the elimination reaction of hydrogen peroxide by AMS and DMS. A conformational analysis and the Fukui function calculation allowed select the initial structure the AMS and DMS, and the target region where these organosulfide compounds can receive a nucleophilic attack by hydrogen peroxide. We analyzed three pathway: 1) Attack on the sulfide atom: an oxidation reaction on the sulfide atom. 2) Attack the vinyl carbon atoms: an epoxidation reaction. 3) Attack the vinyl carbon atoms a hydrogenation reaction. The transitions states in the different pathway were proposed by QST2 approach. Then, we performed the IRC calculations (intrinsic Reaction coordinate) to identify energy profile of the each pathway. We found the three reaction analyzed are thermodynamically feasible whereas the oxidation reaction is the pathway kinetically favored.