Ameliorative Potentials of Camellia sinensis on Petrol Fumes- induced Oxidative Stress in Rats

Volatile organic compounds found in petrol include benzene, toluene, ethylbenzene, and xylene (BTEX). Extract of Camellia sinensis (tea plant) leaf contains some secondary metabolites such as flavonoids, alkaloids, terpenoids saponins, anthraquinones, and tannins. Polyphenols in Camellia sinensis possess anti-atherosclerosis and cardioprotective, neuroprotective, anti-inflammatory, anti-carcinogenic, antibacterial, anti-diabetic, anti-tumor, anti-hypertensive, and hepato-protective effects. The study aimed to investigate the potential of Camellia sinensis in ameliorating lung damage, oxidative stress, and inflammation caused by petrol fumes. Forty-eight Wistar albino rats weighing between 140g-230g  were randomized into 8 groups of 6 rats each consisting of control, petrol fumes only group, three aqueous drink groups of different doses, and three methanol extract groups of different doses respectively. The oxido-inflammatory responses and histopathological alterations in rat lungs following 6 hours of daily exposure for 30 and 60 days were recorded. Oxidative stress (superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT)) and inflammatory biomarkers namely: Tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6) were evaluated. The biochemical analyses showed that petrol fumes exposure resulted in significant (P<.05) increases in biomarkers of oxidative stress, pro-inflammation cytokines, and reduced GSH levels in rats as well histopathological alteration in lungs. The treated groups showed anti-oxidant properties by the elevation of antioxidant enzymes (CAT, SOD) and non-enzymatic antioxidant (gluthathione) and reduction of MDA levels as well as reversal of alterations in the lungs after histopathological analysis. This study showed that Camellia sinensis leaf aqueous and methanol extract have the potential to attenuate petrol fumes-induced oxidative stress due to its natural bioactive constituents.