Evaluation of anxiolytic effect of Medicago sativa in mice

Context: Medicago sativa Linn. (Leguminosae) has a long tradition of use as an Ayurvedic and Homoeopathic medicine in a variety of central nervous system (CNS) disorders. Traditionally, M. sativa is used to improve the memory, as a rejuvenator, antidiabetic, antioxidant, anti-inflammatory, and in CNS disorders. Despite a long tradition of use, no systematic phytochemical and pharmacological work has been carried out on this potential plant. M. sativa was subjected to preliminary anti-anxiety screening studies, with a view to ascertain the verity of its traditional use as an anxiolytic. Objective: Various extracts, viz., petroleum ether, chloroform, methanol and aqueous extract from the aerial parts of M. sativa was subjected to preliminary anti-anxiety screening studies, with a view to ascertain the truth on evidence of its traditional use as an anxiolytic. Materials and methods: The aerial parts of the plant were extracted using solvents in order of increasing polarity, viz., petroleum ether (60-80 degrees C), chloroform, methanol and distilled water. All the crude extracts were evaluated for anti-anxiety activity in mice using elevated plus-maze apparatus. Diazepam was used as the standard drug. Results: Among all extracts, only the methanol extract exhibited significant (p < 0.05) anti-anxiety activity by increasing the average time spent, and number of entries in open arms at a dose of 100 mg/kg in mice with respect to the vehicle treated control as well as the standard (2 mg/kg). Conclusion: These results suggest that administration of M. sativa exerts anxiolytic effect on mice, and it could serve as a new approach for the treatment of anxiety.