ABSTRACT
Polygala paniculata L. (Polygalaceae) é uma erva que ocorre em todas as regiões do Brasil. No presente trabalho, foram avaliadas as atividades analgésica, através do teste da placa quente, da retirada de cauda e da formalina, e antiedematogênica, através do teste do edema de orelha induzido por óleo de cróton, dos extratos etanólicos obtidos das partes aéreas de Polygala paniculata selvagem e cultivadas por micropropagação. A aplicação oral do extrato etanólico de Polygala paniculata apresentou atividade analgésica, em ratos, tanto em testes de dor induzida por agentes térmicos (testes da placa quente e de retirada da cauda) quanto por agentes químicos (teste da formalina), de modo que os melhores resultados foram obtidos na dose de 400 mg/kg. Também foi observada redução na formação de edema de orelha induzida pela aplicação de óleo de cróton. Os efeitos provocados pelos extratos obtidos a partir das plantas cultivadas in vitro foram menos pronunciados que aqueles produzidos pelos extratos das plantas selvagens, embora ambos tenham sido significativos. Estes resultados sugerem que o extrato etanólico de Polygala paniculata possui atividades analgésica e antiedematogênica.
The ethanolic extracts of Polygala paniculata L. (Polygalaceae), wich is a herbaceous plant widely distributed all over Brazil, were tested for their analgesic effects using hot plate, tail flick and formalin test models, and for their antiedematogenic effects using croton oil induced ear oedema. The ethanolic extracts obtained from wild and micropropagated plants produced analgesic effects against thermal and chemical induced pain. The highest results were observed at the dose of 400 mg/kg. The inhibition of ear oedema in mice was also observed after treatment with ethanolic extract of Polygala paniculata. The effects produced by micropropagated plants were lower than wild plants, whereas both had produced significant effects. These results suggest that the ethanolic extracts from wild and micropropagated Polygala paniculata possess analgesic and antiedematogenic effects.
ABSTRACT
It was previously reported that systemic administration of dipyrone inhibited the tonic component of generalized tonic-clonic seizures in both the electroshock and the audiogenic seizure models. The aim of the present study was to investigate the mechanisms involved in the anticonvulsant action of dipyrone by assessing the role of nitric oxide and opioids in the electroshock (female 60- to 90-day-old Wistar rats, N = 5-11) and audiogenic seizure (female 60- to 90-day-old Wistar audiogenic rats, N = 5-11) models of epilepsy. Naloxone (5 mg/kg, sc) significantly reversed the anticonvulsant effect of dipyrone in rats submitted to the induction of audiogenic seizures (ANOVA/Bonferroni's test), suggesting the involvement of opioid peptides in this action. In the electroshock model no reversal of the anticonvulsant effect of dipyrone by naloxone (5 mg/kg, sc) was demonstrable. The acute (120 mg/kg, ip) and chronic (25 mg/kg, ip, twice a day/4 days) administration of L-NOARG did not reverse the anticonvulsant action of dipyrone in the audiogenic seizure model, suggesting that the nitric oxide pathway does not participate in such effect. Indomethacin (10, 20 and 30 mg/kg, ip) used for comparison had no anticonvulsant effect in the audiogenic seizure model. In conclusion, opioid peptides but not nitric oxide seem to be involved in the anticonvulsant action of dipyrone in audiogenic seizures