Avaliação do potencial analgésico do extrato aquoso das folhas da Annona crassiflora (Araticum)

• Autor(a) principal: Magon, Renata Foschini
• Data de Publicação: 2019
• Tipo de documento: Trabalho de conclusão de curso
• Idioma: por
• Título da fonte: Repositório Institucional da UFU
• Texto Completo: https://repositorio.ufu.br/handle/123456789/29806
• topic: Annona crassiflora; Placa quente; Formalina; Antinocicepção; Analgesia; CNPQ::CIENCIAS AGRARIAS

Medicinal plants are plant species used for therapeutic and / or prophylactic purposes, actions which are often associated with the presence of secondary metabolites with biological activities, including terpenes, flavanoids, alkaloids and acetogenins. Annona crassiflora (AC) is a typical species of the Brazilian Cerrado and phytochemical studies have detected the presence of these compounds, which have been attributed anti-inflammatory properties. Considering that substances with anti-inflammatory actions can also decrease the production or block the action of algae mediators, such as prostaglandins, histamine, serotonin and bradykinin, it is not uncommon to find drugs that have both pharmacological, analgesic and anti-inflammatory activities. In this study, we investigated possible analgesic effects of the lyophilized aqueous extract of the AC leaves in experimental models in vivo. Different animal models of nociception are well established in the literature, among them the hot plate and formalin tests, which were used in this study. For the preparation of the aqueous extract, the leaves of the CA were collected in spontaneous vegetation fields at Fazenda Santa Rita in Lassance, MG. After being selected and washed, the leaves were dried in an oven at 45ºC for 48 hours. Then, the dried leaves were crushed and placed in a beaker containing 10% (m / v) distilled water for 48 hours at room temperature. The extract obtained was double filtered, in cotton and filter paper, frozen at - 20 oC and, later, lyophilized. The freeze-dried aqueous extract of A. crassiflora (EAAC) was stored at - 20 oC until the moment of use. For the hot plate and formalin tests, BALB / c mice were used, divided into five groups (G1 to G5), which received the following treatments, orally: G1 = 0.5% carboxymethylcellulose (CBX); G2 = indomethacin (INDO); G3 = EAAC 30 mg / kg; G4 = EAAC 55 mg / kg; G5 = EAAC 100 mg / kg. In the hot plate test, the indomethacin-treated group was not used. In this test, after 0, 30, 60 and 90 minutes the oral treatments, the latency time was evaluated, that is, the time, in seconds, for the animal, in each experimental group, to show the first nociception reactions (jumps , licking, removing or shaking the legs of the hind or forelimbs). In the formalin test, after 60 minutes of treatment by v.o., animals in all experimental groups, including the group treated with indomethacin, received an intraplantar injection of 2% formalin in the right posterior paw (20 μl / paw). Then, each animal was placed individually in the open field apparatus for behavioral observation. Then, the total time that the animal had reactions indicating pain in the intervals from 0 to 15 and from 15 to 30 minutes was recorded. In general, the results obtained showed that EAAC did not induce a statistically significant effect of thermal hypoalgesia in the experimental conditions used; in the formalin test, in the first phase (0-15 min), EAAC produced a dose-independent antinociceptive effect, compared to the negative control group treated with CBX. However, an antinociceptive effect was not observed in the second phase of the test. Taken together, the results obtained suggest that EAAC has an antinociceptive effect due, at least in part, to the possible inhibition of peripheral nociceptive pathways.