摘要Objective: To elucidate the anxiolytic and free radical scavenging effect of methanolic extract of Apium graveolens (A. graveolens) in adult C57BL/6 mice. <br> Methods: Sixty male mice were divided into 6 groups:control, vehicle, positive control and A. graveolens (125, 250 and 500 mg/kg). Different behavioral models of elevated plus maze, open field, light/dark, hole-board and pentobarbital-induced sleep were used to assess anxiety-like behavior. Biochemical parameters including monoamine oxidase-A (MAO-A) activity, lipid peroxidation,%inhibition of superoxide anion and glutathione peroxidase activity were measured. Histologic studies were also examined. <br> Results: Mice receiving various doses of A. graveolens (125, 250 and 500 mg/kg) showed an alleviation of anxiety-like behavior as evidenced by the battery of behavioral tests. Likewise, A. graveolens treatment was found to significantly decrease MAO-A activity, lipid peroxidation as well as cause a significant increase of%inhibition of su-peroxide anion and glutathione peroxidase activity in both cortex and striatum. The total number of survival neurons found in the frontal cortex and striatum was significantly higher than that of the vehicle-treated group. <br> Conclusions: Taken together, we showed that A. graveolens improve the behavioral changes which might be related to the inhibition of free radicals and modulation of MAO-A activity resulting in an increased number of survival neurons. Our findings suggest the therapeutic potential of A. graveolens in the treatment of anxiety.