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 (ED (50)) and 95 % confidence limits (CL (50)) 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 [ED (50) (CL (50)) = 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.