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Gastric ulcer affects people worldwide, and its inefficacy and recurrence have fueled the search for new therapeutic strategies. Despite the well-known use of allantoin in medicines and cosmetic products, its effect has not yet been studied with regard to gastric ulcer. Hence, the aim of the present study was to explore the pharmaco-mechanistic efficacy of allantoin against commonly harmful agents that cause injuries to the stomach. Ethanol, indomethacin, and stress-induced gastric ulcer models were adopted, in addition to pylorus ligature, a quantification of vascular permeability, glutathione (GSH), gastric adhered mucus, prostaglandin (PGE 2 ), pro-inflammatory cytokines levels, myeloperoxidase (MPO), and catalase (CAT) activities. The gastric lesions were examined by gross, histological, and ultrastructural features. The results showed that treatment with allantoin (60mg/kg, per oral) reduced the gastric ulcer formation in all models. Furthermore, allantoin reduced the parameters of gastric acid secretion and attenuated both the vascular permeability and MPO activity. The levels of pro-inflammatory cytokines were also reduced, accompanied by a restoration of CAT activity and GSH levels. Notably, allantoin treatment preserved the gastric-adhered mucus and PGE 2 levels after ethanol administration. Microscopic and ultrastructural analysis revealed that allantoin maintained tissue integrity and prevented morphological changes in cells caused by ethanol. In summary, we demonstrated for the first time that allantoin possesses gastroprotective activity through anti-inflammatory, anti-oxidative, antisecretory, and cytoprotective mechanisms. The antisecretory and cytoprotective mechanisms are probably associated with an increase in PGE 2 levels., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: The leaves and stems bark of Memora nodosa (Silva Manso) Miers (Bignoniaceae) are used in Brazilian traditional medicine in the treatment of external ulcers and wounds; its roots are used to treat abdominal pain and scabies., Aim of the Study: Our aim was to evaluate the antinociceptive and anti-inflammatory activities of Memora nodosa roots ethanolic extract (EMN) and allantoin, a secondary metabolite isolated from this plant., Materials and Methods: The EMN and allantoin antinociceptive activity were evaluated in mice using both chemical and heat-induced pain models such as acetic acid-induced writhing, formalin and tail-flick tests. In the formalin test, a pre-treatment with naloxone was used to verify an involvement of opioid receptor in the antinociceptive effect of EMN and allantoin. Pre-treatment with glibenclemide was used to verity an involvement of ATP-sensitive K(+)channel in the allantoin antinociceptive effect. EMN and allantoin anti-inflammatory activity were assessed by carrageenan-induced paw edema and pleurisy tests., Results: The treatment with EMN (250, 500 and 1000mg/kg, p.o.) inhibit the acetic acid and formalin (both phases)-induced nociception. However, just at doses 500 and 1000mg/kg increased the latency time in tail-flick test. These results suggest the involvement of both peripheral and central antinociceptive mechanisms. The treatment with allantoin (40, 60 and 80mg/kg p.o.) produced a dose-dependent antinociceptive effect in both phases of formalin-induced nociception test; allantoin (60mg/kg) was not able to increase the latency time in tail flick-test. The pre-treatment with naloxone completely reversed the EMN (1000mg/kg) and allantoin (60mg/kg) effect in the first phase of formalin test; and glibenclamide reversed the allantoin effect. The administration of EMN (250, 500 and 1000mg/kg) and allantoin (60mg/kg) showed significant anti-inflammatory activity in the whole carrageenan-induced paw edema. Furthermore, EMN and allantoin reduced the leukocytes migration and pleural exudate to the pleural cavity., Conclusion: EMN have significant antinociceptive and anti-inflammatory effects, which appear to be, at least in part, due to the presence of allantoin. However, allantoin is not responsible for the EMN central antinociceptive activity. Allantoin has peripheral antinociceptive activity that involves the opioid receptor and ATP-sensitive K(+)channels. Opioid receptors are also involved in the EMN antinociceptive activity. These findings support the use of Memora nodosa in popular medicine and demonstrate that this plant has therapeutic potential for the development of antinociceptive and anti-inflammatory phytomedicines., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)