LAUSR

Benzo(a)pyrene [B(a)P] is a well‐known carcinogen present in the environment. In this study, we evaluated the protective potential of methanolic bark extract of Acacia catechu Willd. (MEBA) against the lung toxicity induced by B(a)P in Swiss albino mice. To determine the protective efficacy of MEBA, it was orally administered to the mice at two doses (200 and 400 mg/kg body weight) once daily for 7 days. Mice were also exposed (orally) to B(a)P at a dose of 125 mg/kg body weight on 7th day. Administration of B(a)P increased the activities of toxicity markers such as LDH, LPO, and XO with a subsequent decrease in the activities of tissue anti‐oxidant armory (CAT, SOD, GST, GPx, GR, QR, and GSH). It also caused activation of the apoptotic and inflammatory pathway by upregulation of TNF‐α, NF‐kB, COX‐2, p53, bax, caspase‐3, and downregulating Bcl‐2. Pretreatment with MEBA at two different doses (200 and 400 mg/kg body weight) significantly ameliorates B(a)P‐induced increased toxicity markers and activities of detoxifying enzymes along with the levels of glutathione content. It also significantly attenuated expression of apoptotic and inflammatory markers in the lungs. Histological results further confirmed the protective role of MEBA against B(a)P‐induced lung toxicity. The results indicate that MEBA may be beneficial in ameliorating the B(a)P‐induced oxidative stress, inflammation, and apoptosis in the lungs of mice. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1566–1577, 2017.