Palmitone isolated from Annona diversifolia induces an anxiolytic-like effect in mice

The aim of this study was to investigate the behavioral effects of palmitone in the anti-anxiety response in experimental models in mice. In the elevated plus-maze test, palmitone (0.3, 1, 3, 10 and 30 mg/kg, i.p.) lengthened, from 50% to 199%, the time spent in the open arm region of the maze at all doses tested, as compared to the vehicle group (P < 0.001). In relation to the rearing activity in the exploratory cylinder, palmitone significantly modified (P < 0.05), in a dose-dependent manner, this activity by decreasing the number of rearings with an effective dose value (ED50) and 95% confidence limits (CL50) of 0.79 (0.23-2.68) mg/kg. In addition, in the hole-board test, nose-poking was also significantly decreased (P < 0.01) in a dose-dependent fashion [ED50(CL50) = 9.07 (4.51-18.26) mg/kg]. Moreover, palmitone at any dose caused no change in motor activity nor disruption in traction performance. In contrast, diazepam, used as reference drug, produced an anxiolytic effect with a significant and dose-dependent decrease in motor coordination accompanied by disruption of the traction performance. Behavioral studies suggest an anti-anxiety effect produced by palmitone, but its neuropharmacological profile differs from that observed for benzodiazepines such as diazepam.