Antidepressant Effect of Sour Orange flowers Extract on Lipopolysaccharide-induced Depressive-like Behaviors in Rat

Introduction: Based on the documents in traditional medicine regarding the therapeutic effect of Sour orange flowers (Citrus aurantium L.) on the nervous system disorders, this experimental study was conducted to evaluate the pretreatment of Sour orange flowers extract in preventing or reducing depressive-like behaviors induced by systemic injection of lipopolysaccharide (LPS) in rats. Method: To perform this study, percolated extract of sour orange flowers was used. Each experimental group of animals was pretreated with the extract along with drinking water before the injection of LPS. The depressive-like behaviors induced by the injection of LPS consisted of the reduction in the preference for sucrose solutions, food consumption, body weight and inability to pleasure. Results: The LPS-injected rats that were chronically pretreated with the extract improved sucrose preference compared with control group, however this was not significant. Food consumption in extract-pretreated group was significantly increased on day 2 and 3 after the injection of LPS compared with control group (P<0.05). The effect of extract and LPS on social interaction (consisting of body sniffing and grooming) showed that in extract pretreated rats, the time spent for social interaction was equal to that before the injection (baseline). However in control group there was a significant reduction in the time spent for social interaction compared to the baseline. Conclusion: Considering the effect of LPS in reduction of neurotransmitters such as serotonin and norepinephrine, the attenuation of Sour orange flowers extract on the effect of LPS might be the result of the effect of extract in increasing the level of these neurotransmitter at their site of the activity. To confirm this, more studies to evaluate the pharmacological effect of extract are required.