We investigate the antioxidant activity and protective effects of the aqueous leaf extract of Pistacia lentiscus (AELPL) against ulcerative colitis induced by acetic acid infusion through the rectum in Wistar rats. Phytochemical analyses allowed the identification of numerous phenolic compounds in P. lentiscus leaves such as flavonoids (isoquercetin and luterolin), flavonols (catechin, rutin, and kaempferol), phenolic acids (ellagic and dicaffeoylquinic), and tanins. Acetic acid exposure induced macroscopic colonic mucosal lesions with hemorrhage, congestion, edema, and the development of an expected oxidative stress state revealed by an increase in lipoperoxidation and carbonylation of proteins and a decrease in sulfhydryl (SH) group levels and antioxidant enzyme activities such as superoxide dismutase, catalase, glutathione-S-peroxidase, and glutathione transferase, as well as an increase in the inflammatory cytokine, interleukin-6, in the colon and plasma. Administration of acetic acid also increased plasma and tissue levels of hydrogen peroxide and rates of iron and free calcium, whereas AELPL significantly and dose-dependently attenuated all the previous biochemical alterations and intracellular mediator perturbations. In conclusion, the AELPL exhibited a potent cytoprotective effect against acetic acid-induced colitis in rats, mainly through its antioxidant and anti-inflammatory activities.
Keywords: Pistacia lentiscus; colitis; oxidative stress; polyphenols; rat.