Introduction: Anxiety disorders are one of the most common psychiatric diseases and associated with the serious disease like. Despite numerous anti-anxiety drugs, the treatment of anxiety have still several limitations, such as side effects, long latency and treatment resistance. So, searching for safer and more efficient anti-anxiety agents are necessary. The natural products can suggested as the safe therapeutic agents. Among them, the plant seed oil as the rich source of essential fatty acids can be a candidate for treatment of neurological disorders. Nano-emulsions, a safe technique, improve the bioactivity of the lipid-based substances through increase the solubility. In this study, we evaluated the effect of nanoemulsion of Echium seed oil (NEEO) on anxiety-like behavior induced by chronic unpredictable mild stress (CUMS). Material and methods: In this study, mice were subjected to several mild stressors on a weekly schedule for 4weeks: deprivation of food and water (24h), exposure to an empty bottle (1h), experiencing reversed light/dark (24h), cage tilting 45°, keeping in the wet cage, physical restraint (2h), and exposing to a foreign object (24h). Then, mice were randomly divided into 3groups (n=8 in each), including CUMS, CUMS+100 and CUMS+250. NEEO were administered orally once a day for 4weeks. During the treatment, CUMS procedure was completely considered. Control group did not receive stress or treatment. The elevated plus maze test was performed, and the ratio of the time spent in the open arm/the total time spent in all arms was measured as the anxiety index. Results: compared to control, ratio time of open arm decreased in CUMS. Both doses of NEEO, increased the ratio time of open arm vs. CUMS. But, data was not significant. Conclusion: NEEO administration can partially inhibit anxiety-like behavior induced by CUMS; but the evaluation of higher doses of NEEO, and other anxiety parameters were suggested.
