Antinociceptive and anti-inflammatory effects of the essential oil from Eremanthus erythropappus leaves.

The chemical composition of the essential oil from air-dried leaves of Eremanthus erythropappus was studied. The main compounds wereβ-pinene (23.24%),β-caryophyllene (22.92%),β-myrcene (10.03%) and germacrene D (9.40%). The essential oil had an LD50 of 2.90 g kg&minus1in mice. Doses of 200 and 400 mg kg&minus1 inhibited 10.69% and 27.06% of acetic-acid-induced writhing in mice, respectively. In the formalin-induced nociception test in mice, the essential oil inhibited the first phase of paw licking by 29.13% (400 mg kg&minus1) and the second phase by 32.74% (200 mg kg&minus1) and 37.55% (400 mg kg&minus1). In the hot-plate test in mice, doses of 200 mg kg&minus1 and 400 mg kg&minus1 significantly increased the reaction time after 30, 60 and 90 min of treatment. Doses of 200 and 400 mg kg&minus1 inhibited carrageenan-induced paw oedema in rats by 15.18% and 36.61%, respectively. Doses of 200 and 400 mg kg&minus1 administered 4 h before intrapleural injection of carrageenan significantly reduced exudate volume (by 20.20% and 48.70%, respectively) and leucocyte mobilization (by 5.88% and 17.29%, respectively). These results demonstrate that E. erythropappus has analgesic and anti-inflammatory properties, supporting the use of this plant in folk medicine. [ABSTRACT FROM AUTHOR]