Atividade analgesica e antiulcerogenica de quatro extratos de diferentes polaridades obtidos a partir das cascas de Quassia amara L




Quassia amara L., is a small tree 2-6 m in height, which occur in northern Brazil, Venezuela, Surinam, Colombia, Panamá and Guiana; in Brazil, this species is cultivated from the border with Guiana to the state of Maranhão. The bark wood of this plant is reputed in traditional medicine as having antimicrobial, antianemic and antimalarial activities, as well as being useful for the treatment of digestive disorders, including the gastric ulcers. Moreover Quassia amara is knowed by folk medicine by your narcotic properties. Phytochemical analysis has identified numerous compounds from Quassia amara, including indole and cantinones alkaloids, triterpenes, steroids, and many bitter compounds know as quassinoids. Considering the use of this plant in Brazilian folk medicine and the numerous chemical substances identified from Quassia amara bark, we have evaluated the antinociceptive and anti-inflammatory effects of four bark extracts of different polarities using the hot-plate analgesic test and paw edema in mice. The possible mechanism s involved in the antinociceptive effect of this plant were investigated. When the extracts were administered byoral route (250 mg/kg), it was no observed that significant results in the paw edema and hot plate test (p>0.05); however, The DCM (100 mg/kg) and HEX extracts (100, 250 and 500 mg/kg) when administered in the hot plate test by intraperitoneal route showed an increase in the pain threshold. HEX the more active extract showed an increase in the pain threshold at dependent dose. We performed the hot plate test with the pre-treatment with naloxone, a specific opioid antagonist to evaluate the possible involvement of this activity with the opioid or opioidergic system. The data showed that this analgesic effect of these extracts was reverted by previously administration of naloxone (p<0.05). The compound(s) in the HEX extract are probabely the alkaloids and/or steroids. The antiulcerogenic activities of these extracts administered by oral route at dose of 100 mg/kg. The ethanolic (EtOH), DCM and HEX extracts reduced the ulcerative lesion index in experiments which lesions were induced with HCI-ethanol in mice. In ulcers induced by Nsaids-parassimpathomimetic drugs in mice, the DCM and HEX extracts inhibited significantly the ulcerogenic lesions. The gastric ulcer induced cold and restrain (stress) in mice, showed that ali the extracts inhibited the lesion index. When evaluated the biochemical parameters in the pylorus ligature, the EtOH, DCM and HEX increased pH and reduced the amount of volume and ionizable H+ ions of gastric content. The antiulcerogenic mechanism remains uncertain. However, in the antiulcerogenic activities we emphasize the presence of bitter principies quassinoids. Most probably this group of compounds seems to be involved in an increase of the defense mechanisms of gastric mucosa and/or antisecretory mechanisms. These results confirmed the utilization by folk medicine of bark from Quassía amara to treatment of the dolorous process and gastric ulcers


inflamação ulcera peptica plantas medicinais analgesia

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