Ação antinociceptiva e anti-inflamatória da fração acetato de etila da casca da Scutia buxifolia Reiss em camundongos

Abstract

Pain and inflammation are physiological processes, which when persist can be harmful to health. The pain when improperly or left untreated can become chronic pain. Moreover, the inflammation can be involved in the pathogenesis and progression of many inflammatory diseases. Over the years, it has been shown that natural products can be sources of several molecules diversity leading to drug discovery currently used in modern medicine, especially in the treatment of pain. Published data show that this species Scutia buxifolia Reiss, popularly called “coronilha”, presents phenolic compounds in its composition, including flavonoids, which are able to capture free radicals and prevent diseases resulting from oxidative stress. The objective of this work was to evaluate the antinociceptive and anti-inflammatory action of ethyl acetate fraction (Eta) from the bark of the stem of Scutia buxifolia Reiss in mice. For this screening were performed templates to new analgesic-induced chemical stimulus (formalin, acetic acid, capsaicin) and thermal (hot plate). It was also analyzed Eta activity against inflammation caused by carrageenan through dosages of inflammatory markers (tumor necrosis factor, interleukins, protein c reactive and interferon γ). E finally antinociceptive activity was investigated in a model Eta postoperative pain. Oral administration Eta inhibited nociception caused by acetic acid (Imax 59%±2.3), formalin (Imax 91±9.0%) and capsaicin (Imax 89.3±3.2%). In addition, the Eta administration inhibited the increase of mieloperoxisase activity (Imax 98%±0.2), the levels of nitric oxide (Imax 68±0.6%) and inteleucina (IL)-1 (Imax100%), IL-6 (Imax100%), tumor necrosis factor-α (Imax100%), interferon-γ (Imax100%) and C-reactive protein (Imax 98±0.05%) and was able to increase IL-10 levels (Imax 95±3.3%) in the carrageenan-induced inflammation in mice. Eta also reduced the mechanical hyperalgesia in a model of postoperative pain. However, Eta did not inhibit the thermal hyperalgesia in the hot plate test and its antinociceptive effect in the capsaicin test was not reversed by naloxone opioid receptor antagonist. These results demonstrated that Eta presents antinociceptive and anti-inflammatory activity in mice independent of opioid system and without causing significant advers effects such as changes in locomotor activity, body temperature or causing gastric lesions. In addition, Eta neither alter alanine aminotransferase (ALT) and aspartate aminotransferase (AST) enzymes activities, nor creatinine or urea levels. Taken together, these results support the use of the Eta for the treatment of painfull conditions, especially postoperative pain.