Abstract This study aimed to assess the anxiolytic and sedative properties and influence on biochemical stress markers of aqueous extract of seeds of Picralima nitida staph . The effects of three doses (25, 50 and 90 mg/kg) administered per os have been compared to distilled water as negative control and 5 mg/kg (or 30 mg/kg) of intraperitoneal diazepam as positive control for anxiety test (or sedation test). Firstly the extract was screened to identify the major active compounds. Then behavioral tests including Elevated Plus-Maze (EPM), Open Field (OF), and Hole-board (HB) were used to assess the level of anxiety in different treatments, and potentiation of diazepam-induced sleep test for sedation, Forced Swim Test (FST) to induce chronic stress. After FST, markers of oxidative stress were measured. Results indicate that the extract of P. nitida possesses alkaloids, saponins, flavonoids, tannins, and polyphenols. The EPM-test indicates that at all the doses used, P. nitida induced an increase of open arms time. In the OF-test, P. nitida at doses 25 and 50mg/kg significantly increased the number of crossing as well as central time. In the HB-test, the extract induced an increase of head-dip number and duration. Extract at 25mg/kg increased the duration of diazepam-induced sleep. Biochemical studies have shown an increase of gamma aminobutyric acid (GABA) and serotonin level, an increase of reduced glutathione (GSH) and superoxide dismutase (SOD) activities in the brain and a decrease of malondialdehyde (MDA). These results indicate that P. nitida can be used as anxiolytic and antioxidant agent.
Keywords stress, anxiety, neurotransmitters, oxidative stress, acute stress, chronical stress.