Anti-inflammatory and antinociceptive activity of epiisopiloturine, an imidazole alkaloid isolated from Pilocarpus microphyllus.

The aim of this study was to investigate the antinociceptive and anti-inflammatory activities of epiisopiloturine (1), an imidazole alkaloid found in the leaves of Pilocarpus microphyllus. The anti-inflammatory activity of 1 was evaluated using several agents that induce paw edemaand peritonitis in Swiss mice. Paw tissue and peritoneal fluidsamples were obtained to determine myeloperoxidase(MPO) activity or tumor necrosis factor (TNF)-α and interleukin (IL)-1β levels. The antinociceptive activity was evaluated by acetic acid-induced writhing, the hot plate test, and pain induction using formalin. Compared to vehicle treatment, pretreatment with 1 (0.1, 0.3, and 1 mg/kg, ip) of mice significantly reduced carrageenan-induced paw edema(p < 0.05). Furthermore, compound 1 at a dose of 1 mg/kg effectively inhibited edemainduced by dextran sulfate, serotonin, and bradykinin, but had no effect on histamine-induced edema. The administration of 1 (1 mg/kg) following carrageenan-induced peritonitis reduced tota...