Neurosedative and muscle-relaxant activities of ethyl acetate extract of Baphia nitida AFZEL

The sedative, anxiolytic and muscle-relaxant effects of the ethyl acetate leaf extract of Baphia nitida (BN) was investigated in intact mice, using the hole-board head-dip test for exploratory behavioural effect, elevated plus maze (EPM) and Y-maze (YM) models of anxiety; chimney, inclined screen, traction and climbing tests for muscle-relaxant effects. In each of these tests, BN (100–400 mg/kg, p.o.), diazepam (1 mg/kg, i.p.) or distilled water (10 ml/kg, p.o.) was administered, 30 or 60 min before performing the tests in mice. For exploratory behavioural test, number of head-dip within 15 min was counted. For EPM and YM tests, the cumulative time spent in open and closed arms was recorded within 5 min. In the muscle-relaxant tests, mice were subjected to modified models such as chimney, inclined screen, traction and climbing tests. BN produced a significant (P < 0.05) dose-related decrease in exploratory behaviour in the head-dip test and prolongation of cumulative time spent in open arms of both EPM and YM. BN did not show any significant effect in the chimney and traction tests, but produced significant, dose-dependent muscle relaxation in the inclined screen and climbing tests. Furthermore, BN (200–1200 μg/ml) non-competitively shifted the curves of acetylcholine contractions of the toad Rectus abdominis muscle to the right. Oral doses of BN (0.1–20 g/kg) did not produce mortality, but the LD50 when given intraperitoneally, was 645.65 mg/kg. Results suggest that the leaf extract of Baphia nitida has sedative, anxiolytic and skeletal muscle-relaxant effects and support its neurosedative use in traditional African medicine.