RESUMEN
Calea uniflora Less. (family Asteraceae), also named "arnica" and "erva-de-lagarto", is a native plant to the South and Southeast of Brazil. This species was used to treat rheumatism, respiratory diseases, and digestive problems in Brazilian folk medicine. In vitro studies have shown the important biological effects of C. uniflora. However no studies have focused on the mechanism of action of anti-inflammatory activity of C. uniflora. The aim of this study was to evaluate the anti-inflammatory effects of the crude extract, its fractions, and isolated compounds obtained from of C. uniflora, using mouse model of carrageenan-induced inflammation. The following inflammatory parameters: leukocyte influx, degree of exudation, myeloperoxidase (MPO) and adenosine deaminase (ADA) activities, nitric oxide metabolites (NOx), proinflammatory cytokines and phosphorylation of the p65 subunit of NF-κB (p-p65 NF-κB), and p38 mitogen-activated protein kinase (p-p38 MAPK) levels were determined. The crude extract of C. uniflora, its fractions and its isolated compounds reduced the leukocyte influx, degree of exudation, MPO and ADA activities, NOx, TNF-α, IFN-γ, MCP-1 and IL-6 levels (p<0.05). The isolated compounds reduced p-p65 NF-κB and p-p38 MAPK levels (p<0.01). This study demonstrated that C. uniflora exhibits a significant anti-inflammatory activity via inhibition of the leukocyte influx and degree of exudation. These effects were associated with a decrease in the levels of several proinflammatory mediators. The mechanism of the anti-inflammatory action of C. uniflora may be, at least in part, via the inhibition of p65 NF-κB and p38 MAPK activation by the isolated compounds.