RESUMO
Several secondary metabolites have been isolated from Zornia brasiliensis (Leguminosae), mainly flavonoids. These compounds are known for many pharmacological actions, such as antispasmodic and antidiarrheal. Therefore, we evaluated the antidiarrheal effect of the ethanolic extract obtained from Zornia brasiliensis aerial parts (ZB-EtOHAP), as well as its underlying mechanisms. Castor-oil-induced diarrhea, fluid accumulation, and intestinal transit (normal and castor oil induced) were performed to assess the antidiarrheal, antisecretory, and antipropulsive activities of the extract. The involvement of opioid and adrenergic pathways was also investigated. ZB-EtOHAP inhibited, in a dose-dependent manner, both total defecation frequency and the number of watery stools. The extract showed no effect on fluid accumulation or normal intestinal transit. On the other hand, when the animals were pretreated with castor oil, the extract decreased the distance traveled by the marker in the small intestine. Investigation of the involvement of opioid and adrenergic systems showed that the pharmacological potency of the extract did not change in the presence of naloxone, but it was reduced in the presence of yohimbine. The data indicate that Zornia brasiliensis has an antidiarrheal effect due to inhibition of the intestinal motility through adrenergic pathway activation.
RESUMO
Asthma is a chronic inflammatory disease of the airways related to epithelial damage, bronchial hyperresponsiveness to contractile agents, tissue remodeling, and luminal narrowing. Currently, there are many data about the pathophysiology of asthma; however, a new aspect has emerged related to the influence of reactive oxygen and nitrogen species (ROS and RNS) on the origin of this disease. Several studies have shown that an imbalance between the production of ROS and RNS and the antioxidant enzymatic and nonenzymatic systems plays an important role in the pathogenesis of this disease. Considering this aspect, this study is aimed at gathering data from the scientific literature on the role of oxidative distress in the development of inflammatory airway and lung diseases, especially bronchial asthma. For that, articles related to these themes were selected from scientific databases, including human and animal studies. The main findings of this work showed that the respiratory system works as a highly propitious place for the formation of ROS and RNS, especially superoxide anion, hydrogen peroxide, and peroxynitrite, and the epithelial damage is reflected in an important loss of antioxidant defenses that, in turn, culminates in an imbalance and formation of inflammatory and contractile mediators, such as isoprostanes, changes in the activity of protein kinases, and activation of cell proliferation signalling pathways, such as the MAP kinase pathway. Thus, the oxidative imbalance appears as a promising path for future investigations as a therapeutic target for the treatment of asthmatic patients, especially those resistant to currently available therapies.