Antinociceptive and anti-inflammatory effects of Caesalpinia pyramidalis in rodents

Caesalpinia pyramidalis Tul., Fabaceae, is a plant with an anti-inflammatory activity that is used in folk medicine. To evaluate the mechanism of action of this plant, studies were performed on its antinociceptive and anti-inflammatory properties using an ethanol extract (EE) made from the inner bark. Oral treatment of mice with the EE (100, 200, and 400 mg/kg) decreased their acetic acid-induced abdominal writhes (p<0.001) and their formalin-induced paw licking in both the first and second phases (p<0.001). This treatment increased the reaction time of mice on the hot-plate test (400 mg/kg, p<0.05); however, it did not alter their performance on the Rotarod performance test. The carrageenan-induced paw edema in the rats and the leukocyte migration into the peritoneal cavity of the mice were also reduced by the EE given at a dose of 400 mg/kg (p<0.05). In addition, the EE (100-400 mg/kg, v.o.) did not alter the arterial pressure of non-anesthetized rats. In conclusion, the EE of C. pyramidalis shows antinociceptive and anti-inflammatory activities in rodents, supporting the usage of this plant to treat various inflammatory diseases for which it has traditionally been used.