BACKGROUND OF STUDY

 Tobacco smoking is a practice of burning tobacco and inhaling the smoke (consisting of gaseous phases and particles). A more broad definition may include taking tobacco smoke into the mouth, and then releasing it, as is done by some with tobacco pipes and cigars. The practice may have begun as early as 5000-3000 BC (Nagarajet al., 2014).Cigarette smoking is probably the most addictive and dependence producing form of object-specific, self-administered gratification known to man. According to present estimates, tobacco is responsible for causing more than 5 million deaths every year (World Health Organization, 2008).

The harmful effects of cigarette smoking onhuman health have been well documented.It has been known that cigarette smoke carriesaround 4000 chemicals including toxic metals,poisonous gases and free radicals (Schumacher et al., 2009). Amongst theseconstituents, free radicals are considered to be moredangerous as these owing to their unpaired electron

are highly reactive and can cause oxidative damageto biomolecules and biomembranes (Senet al., 2010).

Smoking plays an important role in disturbing the antioxidant balance. Normally blood contains a healthy complement of antioxidants that keep oxidative damage to a minimum. Tobacco smoke contains abundant reactive oxygen species and also activated neutrophils released due to smoking also add to the pool of reactive oxygen species which deplete these antioxidant mechanisms leading to tissue damage (Kumaret al., 2010).

Malondialdehyde is a organic compound with the formula CH2 (CHO). This reactive species occurs naturally and is a marker for oxidative stress.