Alpha-lipoic acid and acetyl l-carnitine: molecular structures, mechanism of action and therapeutic role in otolaryngology

During physiological processes and stressful conditions (pollution, chemical agents, radiation, sports), the body releases free radicals, especially reactive oxygen species (ROS), unstable and particularly reactive molecules. Although the body has developed several defence mechanisms to neutralise free radicals, ROS production can increase in numerous conditions, triggering an imbalance redox condition known as oxidative stress, which affects proteins, lipids and nucleic acids, damaging their structure and their normal functionality. Mitochondria are the major producers of ROS and organelles that undergo the most impacting structural and functional alterations in case of oxidative stress. Mitochondrial dysfunctions caused by ROS accumulation typically result in a decrease in cellular energy production, accelerating the ageing processes and inducing important tissue alterations. The involvement of oxidative stress in the development of various pathological processes, including inner ear disorders and oral-facial pain, is now recognized. In this context, various molecules with antioxidant functions, such as alpha-lipoic acid (ALA) and acetyl L-carnitine (ALCAR), could be useful in inactivating free radicals and triggering chemical reactions to hinder the perpetuation of the inflammatory state.