Sameena Sultan 2014. Reviewing the Protective Role of Antioxidants in Oxidative Stress Caused by Free Radicals Oxygen is essential element for life. Oxidative properties of oxygen play a vital role in diverse biological phenomena. Oxygen has double-edged properties, being ess. Asian Pacific Journal of Health Sciences. 1, 4 (Dec. 2014), 401–406. DOI:https://doi.org/10.21276/apjhs.2014.1.4.15.