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Male Unib-WH rats were pretreated for two weeks with butanolic (BuOH) and ethyl acetate (EtOAc) fractions. Colitis was induced by rectal administration of TNBS, the treatment continued, and animals were sacrificed on day 7 after the TNBS administration. Phytochemical studies were performed in order to provide the characterization of the tannins present in the bark of R. mangle. Results showed that EtOAc fraction increased the levels of IL-10 (∗∗P < 0.01) and diminished the levels of TNF-α (∗∗∗P < 0.001) and IL-6 (∗∗P < 0.01). BuOH fraction reduced the MPO activity (∗∗P < 0.01) and levels of TBARS (∗∗∗P < 0.001); it also increased COX-1 expression, diminished the levels of TNF-α (∗∗∗P < 0.001), and increased the levels of IL-12 (∗∗∗P < 0.001). Besides, both treatments augmented the levels of GSH (∗P < 0.05), the activity of GSH-Px (∗∗P < 0.01 for BuOH fraction and ∗∗∗P < 0.001 for EtOAc fraction), and CAT (∗∗P < 0.01). In conclusion, both treatments ameliorated the injury induced by TNBS through different mechanisms, probably by their chemical composition which directed its activity into an antioxidant or anti-inflammatory response, leading to an immune modulation.

Inflammatory bowel disease (IBD) is a chronic and disrupted inflammation of the gastrointestinal tract. IBD have two main conditions, Crohn's disease and ulcerative colitis, and have been extensively investigated in recent years. Antibiotics derived from salicylates, steroids, immunosuppressors, and anti-TNF therapy are part of the therapeutic arsenal for IBD. However, very often patients stop responding to treatments over the time. In this context, searching for alternative agents is crucial for IBD clinical management. Natural products derived from medicinal plants are an interesting therapeutic alternative, since several studies have proven effective treatments in animal models of intestinal inflammation. Several naturally occurring compounds are potent antioxidants, both as free radical scavengers and as modulators of antioxidant enzymes expression and activity. A number of natural compounds have also been proved to inhibit the release of proinflammatory cytokines, decreasing the activation of nuclear factor κB (NF-κB), which is important to the inflammatory response in IBD. The alkaloids are substances of a very diverse class of plant secondary metabolites; an extensive list of biological activities has been attributed to alkaloids, such as being anticholinergic, antitumor, diuretic, antiviral, antihypertensive, antiulcer, analgesic, and anti-inflammatory. In the present work, studies on the pharmacological activity of alkaloids in experimental models of IBD were reviewed.

Peptic ulcers are a common disorder of the entire gastrointestinal tract, its etiology has not been completely elucidated. The basic physiopathological of peptic ulcers result from an imbalance between some endogenous aggressive factor and cytoprotective factors. The treatment of this disease is usually done with antacids or proton pump, but are currently being used plants derivated compounds. We evaluated the gastroprotective properties and its possible mechanisms of action of the essential oil from Protium heptaphyllum (Aubl.) Marchand, Burseraceae (BB). The formation of ulcers, were evaluated in three experimental models, through the induction of gastric lesions by ethanol, nonsteroidal anti-infl ammatory drugs and acetic acid. The mechanisms of action were evaluated through the pylorus ligature experiment, western blot, GSH, GR, SOD, GPx, MDA and MPO activities. BB signifi cantly inhibited the formation of ulcers induced by the three different models, increased the GSH and GR levels and maintained the same levels of SOD and GPx of the sham group, inhibited MPO and MDA, did not produce signifi cant modifi cation in gastric juice content and showed increased COX-2 and EGF. BB exerts its gastroprotective activity, possibly, by increasing COX-2 and EGF expression and due to its possible antioxidant property.