A new opportunity for N-acetylcysteine. An outline of its classic antioxidant effects and its pharmacological potential as an epigenetic modulator in liver diseases treatment.

Liver diseases represent a worldwide health problem accountable for two million deaths per year. Oxidative stress is critical for the development of these diseases. N-acetyl cysteine (NAC) is effective in preventing liver damage, both in experimental and clinical studies, and evidence has shown that the pharmacodynamic mechanisms of NAC are related to its antioxidant nature and ability to modulate key signaling pathways. Here, we provide a comprehensive description of the beneficial effects of NAC in the treatment of liver diseases, addressing the first evidence of its role as a scavenger and precursor of reduced glutathione, along with studies showing its immunomodulatory action, as well as the ability of NAC to modulate epigenetic hallmarks. We searched the PubMed database using the following keywords: oxidative stress, liver disease, epigenetics, antioxidants, NAC, and antioxidant therapies. There was no time limit to gather all available information on the subject. NAC has shown efficacy in treating liver damage, exerting mechanisms of action different from those of free radical scavengers. Like different antioxidant therapies, its effectiveness and safety are related to the administered dose; therefore, designing new pharmacological formulations for this drug is imperative to achieve an adequate response. Finally, there is still much to explore regarding its effect on epigenetic marker characteristics of liver damage, turning it into a drug with broad therapeutic potential. According to the literature reviewed, NAC could be an appropriate option in clinical studies related to hepatic injury and, in the future, a repurposing alternative for treating liver diseases.