Antidepressant Activity and Mechanism of Aqueous Extract of Vigna Unguiculata ssp. Dekindtiana (L.) Walp Dried Aerial Part in Mice

Abstract

Objective: Vigna unguiculata ssp. dekindtiana (L.) Walp is used in traditional practice to treat depression-like disorders in some communities of Southwest Nigeria. This study investigated the antidepressant-like effects of the aqueous fraction of the dried aerial parts of V. unguiculata ssp. dekindtiana (AFVU). Methodology: AFVU was evaluated for antidepressant effect on the force-swimming test (FST), tail suspension test (TST) and locomotor activity (LC) in the open field test (OFT) using mice; and its probable neural mechanism(s) investigated using various receptor antagonists. Elemental composition (EC) and phyto-constituents of AFVU were analyzed using standard methods. Results: The AFVU (600 and 800 mg/kg, p.o.) significantly (p<0.05) decreased the immobility time of mice in FST and TST without significant (p<0.05) effect on LC, suggesting that its antidepressant-like effect is specific; anti-immobility effect of AFVU was significantly (p<0.05) blocked by intraperitoneal injection of prazosin (62.5 µg/kg), yohimbine, (1 mg/kg), cyproheptadine (3 mg/kg), sulpiride (50 mg/kg), methylene blue (10 mg/kg) and L-NNA (10 mg/kg) suggesting adrenergic, serotonergic, dopaminergic and nitergic pathways. The EC assured its safety; while phenols and alkaloids were the most abundant phytoconstituents in AFVU. Conclusion: This study concluded that AFVU possessed antidepressant-like effects which may be mediated through multiple receptor pathways.