GLUTATHIONE & N-ACETYLCYSTEINE (NAC) - Scientific Paper Abstracts

Altern Med Rev 1998 Apr;3(2):114-27

Clinical applications of N-acetylcysteine.
Kelly GS

Alternative Medicine Review, Greenwich, CT.

N-acetylcysteine (NAC), the acetylated variant of the amino acid L-cysteine, is an excellent source of sulfhydryl (SH) groups, and is converted in the body into metabolites capable of stimulating glutathione (GSH) synthesis, promoting detoxification, and acting directly as free radical scavengers. Administration of NAC has historically been as a mucolytic agent in aof piety of respiratory illnesses; however, it appears to also have beneficial effects in conditions characterized by decreased GSH or oxidative stress, such as HIV infection, cancer, heart disease, and cigarette smoking. An 18-dose oral course of NAC is currently the mainstay of treatment for acetaminophen-induced hepatotoxicity. N-acetylcysteine also appears to have some clinical usefulness as a chelating agent in the treatment of acute heavy metal poisoning, both as an agent capable of protecting the liver and kidney from damage and as an intervention to enhance elimination of the metals.

Chest 1995 May;107(5):1437-41

N-acetylcysteine for lung cancer prevention.
van Zandwijk N

Department of Chest Oncology, The Netherlands, Cancer Institute/Antoni van Leeuwenhoek Huis, Amsterdam.

Lung cancer arises as a focal transformation of chronically injured epithelium with cigarette smoke as one of its well recognized causes. Apart from oxidants, cigarette smoke contains several precarcinogens, and it is surprising that not every heavy smoker becomes a victim of malignant disease. This points to the interindividual variability in susceptibility to carcinogens and there are several lines of evidence that metabolic factors are involved in such variability. Metabolism of carcinogens and also the subsequent multisteps of carcinogenesis are affected by host factors and governed by the balance between opposite forces, such as metabolic activation and detoxification, formation, and scavenging of radicals and DNA damage and repair. This implies that carcinogenic compounds can initiate tumor growth only in amounts saturating detoxification mechanisms. In this context it is well known that glutathione plays a crucial role in the detoxification of xenobiotics. N-acetylcysteine (NAC), an aminothiol and precursor of intracellular cysteine and glutathione, has been shown not only to be an efficient antidote in acetaminophen poisoning but also to possess important chemopreventive properties. In this article, sites and mechanisms of the therapeutic action of NAC are reviewed with special reference to its chemopreventive characteristics.

Respiration 1986;50 Suppl 1:26-30

Acetylcysteine: a drug with an interesting past and a fascinating future.
Ziment I

N-acetylcysteine (NAC) possesses a free sulfhydryl group that can rupture disulfide bridges. Although it is considered to be a mucolytic, its mucokinetic actions include expectorant, bronchorrheic and mucoregulatory contributions. New uses include the management of acetaminophen poisoning and the scavenging of free radicals liberated by cancer chemotherapy drugs. The antioxidant effects may be of prophylactic value in lungs at risk from smoking, pollution and infection. Other uses proposed for NAC include the therapy of connective tissue diseases and its use as a component in life extension diets.

J Cell Biochem Suppl 1995;22:24-32

N-acetylcysteine (NAC) and glutathione (GSH): antioxidant and chemopreventive properties, with special reference to lung cancer.
van Zandwijk N

Department of Chest Oncology, HET Nederlands Kanker Institute, Amsterdam, The Netherlands.

Lung cancer arises as a focal transformation of chronically injured epithelium with cigarette smoke as one of its well-recognized causes. Apart from oxidants (free radicals), cigarette smoke contains such a multitude of (pre) carcinogens that it is astonishing that not every heavy smoker becomes a victim of malignancy. This points to the interindividual variability in susceptibility to carcinogens; several lines of evidence suggest that metabolic factors are involved in such variability. Metabolism of carcinogens as well as the subsequent (multi) steps of carcinogenesis are affected by host factors and governed by the balance between opposing forces, such as metabolic activation and detoxification, formation and scavenging of radicals, and DNA damage and repair, which seem to imply that carcinogenic compounds can initiate tumor growth only in amounts saturating detoxification mechanisms. In this context it is well known that glutathione (GSH) plays a crucial role in the detoxification of xenobiotics. N-Acetylcysteine (NAC), an aminothiol and synthetic precursor of intracellular cysteine and GSH, has been used for many years in Europe as a mucolytic drug. Clinically, it is a safe agent without major side effects and has been considered to have a place in cancer prevention, too. The antimutagenic and anticarcinogenic properties of NAC could be ascribed to multiple protective mechanisms, such as NAC nucleophilicity, antioxidant activity, its ability to act as a precursor of intracellular reduced GSH, modulation of detoxification, and DNA repair processes. On these grounds, NAC has emerged as a most promising cancer chemopreventive agent.