Antidepressant effect of methanol root bark extract of Acacia seyal Del. (Fabaceae): Possible involvement of the inflammatory pathway

Purpose: To study the involvement of inflammatory pathways in the antidepressant activity of Acacia seyal in mice. Methods: The median lethal dose (LD50) of the extract Acacia seyal (AS) was determined using OECD guideline 425. The antidepressant activity of AS was assessed against BCG (0.2 mg/kg, ip)-induced depression in mice using Tail suspension test (TST) and open field test (OFT) at 4, 24 and 48 hours post BCG administration. Results: The median lethal dose (LD50) for the extract was > 5000 mg/kg orally. The extract AS at all tested doses (250 - 1000 mg/kg) significantly (p <= 0.001) decreased the duration of immobility in TST but increased the number of line crossing in OFT post-BCG. Conclusion: The antidepressant activity of the methanol root bark extract of Acacia seyal in mice may involve an inflammatory mechanism. Thus, the extract of Acacia seyal may be suitable for the management of depression in humans resistant to other conventional antidepressant agents. However, further studies are required to ascertain this