Medical and Dietary Uses of N-Acetylcysteine

Abstract

N-acetylcysteine (NAC), a plant antioxidant naturally found in onion, is a precursor to glutathione. It has been used as a drug since the 1960s and is listed on the World Health Organization (WHO) Model List of Essential Medicines as an antidote in poisonings. There are numerous other uses or proposed uses in medicine that are still in preclinical and clinical investigations. NAC is also used in food supplements and cosmetics. Despite its abundant use, there are projections that the NAC global market will grow in the next five years; therefore, the purpose of this work is to provide a balanced view of further uses of NAC as a dietary supplement. Although NAC is considered a safe substance, the results among clinical trials are sometimes controversial or incomplete, like for many other antioxidants. More clinical trials are underway that will improve our understanding of NAC applicability.

Reduction of oxidative stress improves insulin signaling in cardiac tissue of obese mice

“…N-acetylcysteine is a compound often employed in clinical practice as a mucolytic agent to treat paracetamol overdoses and prevent free radical generation by toxic substances. (13) Its antioxidant activity is related mainly to the reduction of the extracellular amino acid cystine into the intracellular amino acid cysteine, and to the donation of thiol groups to reduced glutathione. (14) Moreover, NAC can promote the direct neutralization of ROS as the radical hydroxyl and hypochlorous acid, thus preventing the occurrence of oxidative stress and its possible consequences over insulin resistance.…”

Oral N-Acetyl Cysteine Administration Improved Oxidative Status in Medical Radiation Workers

“…NAC has a powerful influence on diseases and states characterized by the production of free oxygen radicals. It protects mice from gastrointestinal death after abdominal irradiation where administration of NAC restored mice's duodenal structure exposed to 20 Gy and mitigated the life shortening induced by chronic exposure to low dose rate of radiation in mice [7,20,[29][30][31]. GSH levels in MRWs supported with oral administration of NAC (600 mg) twice daily for two months were significantly increased by 4.6 times than before administration of NAC.…”

“…These results are in agreement with many previous studies which stressed that chronic exposure to low doses of IR caused an increase in the oxidative stress molecules as MDA which is the most mutagenic product that resulted from peroxidation of lipids when ROS oxidizes lipids and leading to tissue damage and cell membrane damage. This harmful effect is the molecular base for disruption of signal transduction, gene expression and regulation of cell functions involved in apoptosis, adaptation and genomic instability which are directly associated to carcinogenesis [7,27,36].…”

“…Cellular oxidative stress depletes reduced glutathione (GSH), which is associated with many pathological disorders. It is a crucial protecting molecule in cells against damage of free radicals as it may act as a substrate or cofactor of antioxidant enzymes and as a perfect radical trapping [7]. Reactive oxygen species disrupt membrane structure and function via oxidative damage of polyunsaturated fatty acids found in the cell membranes and also produces potentially mutagenic and carcinogenic byproducts.…”

“…It has been used as antidote to acetaminophen overdose. [7,[12][13][14][15] It was approved by the Food and Drug Administration and used as a dietary antioxidant supplement. It is a small thiol molecule that protect healthy cells against radiation induced genotoxicity [16].…”