N-Acetylcysteine: A Review of Clinical Usefulness (an Old Drug with New Tricks)
Table 1
N-acetylcysteine (NAC) potential mechanisms of action.
1
Action on glutathione
NAC restores glutathione (cysteine is rate limiting) [5] as seen in cell and animal studies and clinically in acetaminophen overdose.
2
Stabilizes proteins/DNA
Protects proteins by crosslinking cysteine disulfide molecules [6]. Various mechanisms of DNA repair/protection [7] as seen in animal studies and human cell studies.
3
Scavenges free radicals
Scavenging property via the redox potential of thiols [8] as demonstrated in cell culture.
4
Anti-inflammatory property
Reduces proinflammatory cytokines [9] as seen in animal studies.
5
Antioxidant property
Reduces oxidative damage [10] as seen in cell cultures.
6
Mucolytic property
Splits disulfide bonds in mucoproteins lowering viscosity [11] demonstrated in purified mucus gels and tracheal explant systems and in vitro (in a pig tracheal pouch) models.
7
Mitochondrial resilience
Neurogenesis-inducing ability [12] reduces apoptosis of mitochondria [13] as demonstrated in human dental pulp cells.
8
Metal chelation
Thiol groups provide binding sites for metals [14] in animal studies.
9
Glutamate/dopamine homeostasis
Modulates glutamate and dopamine [15] extensive studies in humans.
10
Antiviral properties
Immune modulation, anti-NF-KB properties, and other unexplored mechanisms [16] observed in vitro and in vivo.
11
Vascular endothelial growth factor
Inhibition of vascular permeability [17] as seen in human keratinocytes.
12
Adenosine triphosphate (ATP) and nitric oxide (NO) production
Increased ATP production in some cells like fibroblasts in vitro [18]. Increased nitric oxide production [19] as demonstrated in human studies.