ABSTRACT
Free radicals are produced by regular cellular metabolism. These are highly reactive molecules which can damage or alter the cellular structures, namely carbohydrates, lipid, proteins, and nucleic acids. The alteration in the steadiness between free radicals and antioxidants in favor of free radicals is defined as “oxidative stress.” Oxidative stress leads to the development of a wide range of pathological conditions and diseases such as cancer, atherosclerosis, hypertension, diabetes, chronic obstructive pulmonary disease, neurological disorders, and asthma. Phytochemicals influencing animal metabolism are being broadly examined for their potential health benefits. Physiological benefits of phytochemicals could be explained by molecular basis of the antioxidant action including their basic mechanisms, targeting signal transduction pathways, especially through the antioxidant response element/nuclear factor (erythroid-derived 2)-like two transcription system. The understanding of the molecular concept of the biological activity of phytoconstituents provides scientific validation to defend their use in foods. The current chapter summarizes the anomalies of oxidative stress, their biomarkers and ameliorative effects of phytochemicals.
