Pharmacological and dietary antioxidant therapies for chronic obstructive pulmonary disease

The progression and exacerbations of chronic obstructive pulmonary disease (COPD) are intimately associated with tobacco smoke/biomass fuel-induced oxidative and aldehyde/carbonyl stress. Alterations in redox signaling proinflammatory kinases and transcription factors, steroid resistance, unfolded protein response, mucus hypersecretion, extracellular matrix remodeling, autophagy/apoptosis, epigenetic changes, cellular senescence/aging, endothelial dysfunction, autoimmunity, and skeletal muscle dysfunction are some of the pathological hallmarks of COPD. In light of the above it would be prudent to target systemic and local oxidative stress with agents that can modulate the antioxidants/ redox system or by boosting the endogenous levels of antioxidants for the treatment and management of COPD. Identification of various antioxidant agents, such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine, N-acystelyn, erdosteine, fudosteine, ergothioneine, and carbocysteine lysine salt), dietary natural product-derived polyphenols and other compounds (curcumin, resveratrol, green tea catechins, quercetin sulforaphane, lycopene, acai, alpha-lipoic acid, tocotrienols, and apocynin) have made it possible to modulate various biochemical aspects of COPD. Various researches and clinical trials have revealed that these antioxidants can detoxify free radicals and oxidants, control expression of redox and glutathione biosynthesis genes, chromatin remodeling, and ultimately inflammatory gene expression. In addition, modulation of cigarette smoke-induced oxidative stress and related cellular changes have also been reported to be effected by synthetic molecules. This includes specific spin traps like α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419, lipid peroxidation and protein carbonylation blockers/inhibitors, such as edaravone and lazaroids/tirilazad, myeloperoxidase inhibitors, as well as specialized pro-resolving mediators/inflammatory resolving lipid mediators, omega-3 fatty acids, vitamin D, and hydrogen sulfide. According to various studies it appears that the administration of multiple antioxidants could be a more effective mode used in the treatment of COPD. In this review, various pharmacological and dietary approaches to enhance lung antioxidant levels and beneficial effects of antioxidant therapeutics in treating or intervening the progression of COPD have been discussed.