Gastroprotective and anti-Helicobacter pylori potentials of essential oils from the oleoresins of Araucaria bidwillii and Araucaria heterophylla.

Plant resins or oleoresins comprise a chemically complex mixture of different classes of compounds. Oleoresin of the genus Araucaria combines essential oil (EO) and resin. It possesses gastroprotective, cytotoxic, and timicrobial, antipyretic, and anti-inflammatory activities. The study aimed to investigate the EOs from the oleoresins of two Araucaria species, A. bidwillii and A. heterophylla, chemically and biologically for their gastroprotective, anti-inflammatory, antioxidant, and anti-Helicobacter pylori potentials. The chemical composition of both species cultivated in Egypt was analyzed with GC-MS and compared with those cultivated abroad using principal component analysis (PCA). There were 37 and 17 secondary metabolites identified in A. heterophylla and A. bidwillii, respectively. The EOs of both species showed a pronounced inhibitory effect on Helicobacter pylori activity in vitro. The gastroprotective effect was assessed in vivo using ethanol-induced gastric ulcer model in rats. Inflammatory cytokines, oxidative stress, and the nuclear factor-kappa B (NF-κB) biomarkers were assessed in the stomach tissues. The ulcer index and percentage of ulcer protection were determined. Stomach sections were examined histopathologically by staining with (H/E) and periodic acid Schiff (PAS). Moreover, the proliferative index was determined using the Ki-67 immunostaining. The treatment of rats with EOs (50, 100, and 200 mg/kg, orally) 1 hour prior to ethanol administration showed promising gastroprotective, anti-inflammatory, and antioxidant potentials. These findings declared the gastroprotective role played by both EOs with the superiority of A. bidwillii over A. heterophylla via modulation of oxidative stress/NF-κB/inflammatory cytokines. Their use can be recommended to protect against the recurrence of peptic ulcers.