Effects of Daniellia oliveri stem bark and leaf extracts on rat skeletal muscle.

The stem bark and leaves of Daniellia oliveri were screened phytochemically and the effects of their respective methanol extracts on the skeletal muscle of rats were investigated using the isolated phrenic nerve hemidiaphragm muscle preparation. Both were found to contain tannins, cardiac and saponin glycosides. In addition, the bark, but not leaves, contained cyanogenetic glycosides. The methanol extracts were found to possess neuromuscular blocking properties. The leaf extract appeared to act primarily by inhibiting the influx of extracellular Ca(2+) principally by inhibiting K(+) channels. The inhibitory action of the bark extract appeared to be mediated by interference with transmitter release and an action on multiple sites. Copyright 1999 John Wiley & Sons, Ltd.