Double-edged Role of Free Radicals

Objectives: This review aims to comprehensively examine the dual role of free radicals in human physiology and pathology, elucidate their sources and effects on various cell types, and assess the effectiveness and limitations of antioxidant defense systems and therapies in the prevention and treatment of oxidative stress-related diseases. Methods: A systematic search was conducted in PubMed, ScienceDirect, Scopus, and Google Scholar, yielding 638 records. After removing duplicates and applying inclusion criteria focused on the dual role of free radicals in physiology and pathology, 40 peer-reviewed English-language articles were included in the final synthesis, based on relevance, methodological quality, and oxidative stress content. Results: Free radicals, particularly reactive oxygen and nitrogen species, are generated through both endogenous metabolic processes and exogenous factors. While they serve essential physiological roles, their overproduction contributes to oxidative damage implicated in cardiovascular diseases, diabetes, cancer, and neurodegenerative disorders. The body’s antioxidant defenses include enzymatic (SOD, catalase, GPx) and non-enzymatic (vitamins C and E, glutathione, polyphenols) systems. Although antioxidant therapies show promise in preclinical studies, clinical trials reveal inconsistent efficacy due to variable factors such as dosage, timing, and disease context. Conclusion: Free radicals are key players in both cellular signaling and disease pathogenesis. Antioxidant systems are vital for maintaining redox homeostasis, but when overwhelmed, oxidative stress ensues. While antioxidant therapy remains promising, its clinical utility requires further refinement. Future research should prioritize targeted antioxidant delivery and combinational approaches to enhance therapeutic outcomes in oxidative stress-related conditions.