Evaluation of antioxidant and anti-lipid peroxidation potentials of Nigella sativa and onion extract on nicotine-induced lung damage

Background: The present work aimed to compare the protective effect of Nigella sativa (NS) and onion extract on the nicotine-induced lung damage in rats. The antioxidant and anti-lipid peroxidation potentials of both agents on nicotine-induced lung damage were studied. Materials and methods: Thirty-six Sprague-Dawley albino rats, treated for 18 weeks, were divided into six groups: one negative control group, two positive control groups (oral onion and oral NS), nicotine-treated group, onion extract-treated group (concomitant nicotine and onion extract) and NS-treated group (concomitant nicotine and NS oil). The assessment of lung structure was based on haematoxylin and eosin and transmission electron microscopy. Lung malondialdehyde (MDA), superoxide dismutase activity (SOD), catalase (CAT), lung glutathione (GSH), and epithelial lining fluid GSH (ELF GSH) were used for assessment of the antioxidant and anti-lipid peroxidation potentials of NS and onion extract. Results: The lung of the nicotine-treated group exhibited emphysematous air spaces, collapsed corrugated alveoli with ruptured interalveolar septa in some specimen and thickened septa in the others, massive congestion, extravasation of red blood cells, inflammatory cellular infiltration and fluid exudate. Much improvement was observed in the onion-treated group despite the presence of residual pathological affection. The lung in the NS-treated group showed the nearly normal architecture with slight congestion. Administration of nicotine promoted lipid peroxidation (elevation of MDA) and decreased the level of the antioxidant markers (SOD, CAT lung GSH and ELF GSH). With the use of onion extract and NS, the level of MDA decreased by 17.85% and 35.71% while the levels of SOD, CAT GSH, and ELF GSH increased. The increase was more prominent in the NS-treated group. The levels in the NS-treated group reached nearly the level markers of the control group. Conclusions: Nigella sativa and onion extract attenuate the pathological effect of nicotine in the lung rats through antioxidative and anti-lipid peroxidative mechanisms with higher protection to NS.