N-AAcetyl-L-Cysteine (NAC): A potential green chemical in the alleviation of metal stress

Plants develop a wide variety of methods to cope with the adverse effects of environmental stresses which limit crop productivity. They overcome these effects by developing sophisticated mechanisms for recognising environmental signals depending on species-specific degrees of tolerance. These stress factors induce the overproduction of reactive oxygen species (ROS), leading to the breakdown of vital macromolecules and damage to cell structures. The protective role of various chemical substances applied exogenously to plants has become an important subject of study for alleviating the damage resulting from stress factors. One such compound is the glutathione precursor N-acetyl-L-cysteine (NAC) derived from cysteine. Human health-related studies have established NAC as a potent therapeutic agent in numerous disorders. A limited number of studies have also demonstrated that exogenous NAC application to plants alleviated the adverse effects of biotic and abiotic stresses and induced resilience to external factors. This review is intended to highlight the effectiveness of NAC in alleviating the deleterious effects of metal stress, a common stress factor limiting crop yields. It also discusses the role of NAC in alleviating stress-induced hazards as a key antioxidant which maintains cellular metabolism and enhances stress tolerance.