Biomolecular double bonds and thiol groups

Biomolecular double bonds and thiol groups represent the primary chemical sites of action for ozone and other reactive electrophilic agents within a biological environment. Carbon-carbon double bonds, found extensively in the polyunsaturated fatty acids of cell membranes and lipoproteins, react with ozone via ozonolysis to produce lipid oxidation products like ozonides and aldehydes. Thiol groups, present in the amino acid cysteine and the antioxidant glutathione, are susceptible to oxidation, leading to the formation of disulfides or sulfenic acids. These chemical modifications serve as a trigger for various signal transduction pathways, most notably the Nrf2-mediated antioxidant response, which enhances cellular resistance to oxidative stress. While these interactions underpin the therapeutic potential of oxygen-ozone therapy in treating infections and ischemic conditions, they also represent the molecular basis for toxicity when exposure is excessive or poorly controlled.

Other names

Carbon-carbon double bonds and sulfhydryl groupsOzone molecular targetsPUFA double bonds and cysteine thiolsC=C and -SH groups

Ozone reacts with carbon-carbon double bonds in polyunsaturated fatty acids through ozonolysis, forming ozonides and lipid oxidation products (LOPs) such as 4-hydroxynonenal. Simultaneously, it oxidizes free thiol groups in proteins and glutathione to disulfides or higher oxidation states. These reactions generate transient reactive oxygen species (ROS) like hydrogen peroxide, which act as secondary messengers to activate the Nrf2 antioxidant pathway and modulate immune responses.