Development of
cancer in humans is a multistep process. Complex series of cellular and molecular changes participating in
cancer development are mediated by a diversity of endogenous and exogenous stimuli and important amongst this is generation of
reactive oxygen species (ROS). Reactive radicals and non-radicals are collectively known as ROS. These can produce oxidative damage to the tissues and hence are known as
oxidants in
biological system. Many researchers have documented the role of ROS in both initiation and promotion of multistep
carcinogenesis. To mitigate the harmful effects of
free radicals, all aerobic cells are endowed with extensive
antioxidant defence mechanisms. Lowered
antioxidant capacity or the
oxidant-
antioxidant imbalance can lead to oxidative damage to cellular macromolecules leading to
cancer. Oral cavity
cancer is an important
cancer globally and tobacco is the primary etiological factor in its development. Tobacco consumption exposes the oral epithelium to toxic
oxygen and
nitrogen free radicals that can affect host
antioxidant defence mechanisms. Elevated levels of ROS and
Reactive Nitrogen Species (RNS) and lowered
antioxidants are found in oral precancer and
cancer. Protection can be provided by various
antioxidants against deleterious action of these
free radicals. Treatment with
antioxidants has the potential to prevent, inhibit and reverse the multiple steps involved in oral
carcinogenesis. This review is an attempt to understand the interesting correlation between ROS and RNS mediated cell damage and enzymatic and non-enzymatic defence mechanisms involved in
oral cancer development and its progression and the use of
antioxidants in
oral cancer prevention and treatment.