Protective effects of lemongrass essential oil against benzo(a)pyrene-induced oxidative stress and DNA damage in human embryonic lung fibroblast cells

Benzo(a)pyrene (BaP) was a well-known environmental pollutant, numerous studies had implicated BaP as a causative agent in human cancer, particularly lung cancer. The lemongrass essential oil (LEO) possessed various pharmacological activities, especially the anti-oxidative stress and cancer prevention. In the current study, human embryonic lung fibroblast (HELF) cells were treated with 25mM BaP in the absence or presence of 0.5%, 1% or 2.5% LEO and the cell viability and levels of oxidative stress (OS) and DNA damage in the cells were then measured. Nineteen chemical constituents were identified in LEO, with citral being the main component, representing about 68.78%. LEO was able to protect the HELF cells against BaP-induced loss in cell viability, achieving a maximum of 95.58% cell viability at the 0.5% concentration. Treatment of HELF cells with BaP alone significantly increased the level of Malondialdehyde (MDA) and decreased superoxide dismutase (SOD) and catalase (CAT). However, these effects were suppressed when the cells were also treated with LEO, leading to enhanced levels of SOD and CAT activities (2.9- and 2-fold, respectively, compared with BaP treatment only) and reduced the level of MDA in the cells (43% reduction in malondialdehyde level). At the same time, LEO also reduced the level of DNA damage, as shown by a reduced level of 8-hydroxy-deoxyguanosine (8-OHdG). Taken together, the results showed that LEO offered protection against BaP-induced OS and DNA damage, suggesting that LEO could be a promising agent for lung cancer chemoprevention.