Protective effect of essential oil of Foeniculum vulgare Mill. against bleomycin-induced pulmonary fibrosis and oxidative stress in rat

• Fennel essential oil was rich in estragole, fenchone, limonene and phenolic compounds. • It showed a significant antioxidant potential in TAC, DPPH, RAP and ABTS assays. • The effects on BLM-IPF were revealed by disruption and alteration of oxidative stress biomarkers. • The effect on of BLM-IPF was confirmed by microscopic histological observations. • Fennel essential oil could have promising applications in the pharmaceutical field. Wild fennel ( Foeniculum vulgare Mill.) is a very common plant used in traditional medicine to treat several diseases. In recent years, scientific research proved its biological properties. However, the protective effect of fennel against bleomycin-induced pulmonary fibrosis (BLM-IPF) is not yet study. Fennel essential oil (FEO) composition was characterized and its protective effect was assessed. GC–MS was employed to determine the chemical composition of fennel essential oil. The antioxidant activity was evaluated using TAC, DPPH, RAP and ABTS assays. After inducing fibrosis by bleomycin, several biological assays were used to evaluate the protective effect [proteins content, malondialdehyde MD, thiol group, superoxide dismutase (SOD) and catalase (CAT)]. FEO was rich in estragole (77.55 %), fenchone (9.23 %), and limonene (9.23 %), and phenolic compounds and showed a significant antioxidant potential. The effects on BLM-IPF were revealed by disruption and alteration of oxidative stress biomarkers in lung, liver and kidney. Treatment of rats with FEO improved abnormal fluctuations in protein and thiol levels, decreased oxidative stress in terms of MDA and also restored the response of the antioxidant system, measured in terms of SOD and CAT, in lung, liver and kidney. The biological activity was recorded in a dose response manner. The potential of FEO in limiting the progress of the histopathologic effects of BLM-IPF was confirmed by microscopic histological observations, with a reduction of the fibrosis score and the inflammatory index in the FEO treated lung tissue. These results, proved that FEO could attenuate BLM-induced PF, thus suggesting that the latter could serve as a potential therapeutic approach for PF.