Antioxidants and their impact on human health

Abstract: In recent years, significant attention has been directed toward the field of free radical chemistry. Our bodies naturally produce free radicals, reactive oxygen species (ROS), and reactive nitrogen species (RNS) that are naturally generated within the human body as by-products of various metabolic processes and endogenous production due to exposure to various external environmental factors. Maintaining a balance between these reactive species and antioxidants is crucial for normal physiological functions. Oxidative stress is a key contributor to cellular and molecular damage, affecting vital biomolecules such as lipids, proteins, and nucleic acids. This cumulative damage is implicated in the pathophysiology of numerous chronic and degenerative diseases, including cardiovascular disorders, neurodegenerative conditions (e.g., Alzheimer's and Parkinson's diseases), diabetes mellitus, inflammatory diseases, and various types of cancer. Antioxidants can be derived from both natural and synthetic sources and function by scavenging free radicals, chelating metal ions, or up-regulating endogenous antioxidant defences. Natural antioxidants, commonly found in fruits, vegetables, herbs, and spices, include polyphenols, carotenoids, and essential vitamins. On the other hand, synthetic antioxidants such as butylated hydroxytoluene (BHT) and butylated hydroxyanisole (BHA) are widely used in the food and pharmaceutical industries to prevent oxidation and prolong shelf life. This review aims to provide a comprehensive overview of the various types of antioxidants, their mechanisms of action, and their sources. Furthermore, it highlights the critical role of antioxidants—both natural and synthetic—in the prevention of oxidative stress-related diseases and their potential applications in health promotion and disease management.