Antidepressant, Myorelaxant and Anti-Anxiety-Like Effects of Nauclea latifolia Smith (Rubiaceae) Roots Extract in Murine Models

The neuropharmacological effects of the decoction of Nauclea latifolia Smith (Rubiaceae) roots were studied in mice. Different experimental models (forced swimming test, horizontal wire test and hole-board test) were used for detecting antidepressant, myorelaxant and anxiolytic properties. The results revealed that Nauclea latifolia induced a reduction of immobility, in a similar way to that of fluoxetine, along with a significant increase in the percentage of spent time in swimming behavior. Nauclea latifolia displayed a myorelaxant activity in the horizontal wire test. In the hole-board test, Nauclea latifolia significantly increased the number and duration of head-dips. In addition, anxiolytic-like properties of Nauclea latifolia were blocked by anxiogenic agents as examined in the hole-board test. This was the case for N-methyl- beta -carboline-3-carboxamide (FG7142), a partial inverse agonist at the benzodiazepine site of the GABA sub(A) receptor complex, flumazenil (RO151788), a central benzodiazepine receptor antagonist and bicuculline, a light-sensitive competitive antagonist of GABA sub(A) receptors. These results suggest that Nauclea latifolia roots decoction possess antidepressant, myorelaxant and anti-anxiety-like properties in the models employed. The extracts might potentially act by GABAergic activation and/or by modulating the serotoninergic levels in the central nervous system. However, further studies were still required.