Oxytocic properties of the aqueous extract of Globimetula braunii (loranthaceae).

The leaves of Globimetula braunii are used in ethnomedicine to augment labour. The crude aqueous extract of the plant was tested on isolated rat uteri. The agonistic activity of the aqueous extract was compared with that of a standard uterine stimulant oxytocin and uterine smooth muscle antagonists atropine and salbutamol. The extract was found to exhibit oxytocic activity on the uterine smooth muscle which was less potent than that of oxytocin. The force of contraction (3.60 +/-0.25 g) elicited by the highest concentration of the extract (640 mg/ ml) was similar to that of 2.7 x 10-4 mg / ml of oxytocin (3.61+/-0.17 g). Oxytocin was also observed to significantly (p<0.05) enhance the uterine contractile effect of the extract. The oxytocic effects of the extract was significantly (p<0.05) inhibited by both atropine and salbutamol. The oxytocic effects indicate the presence of active principle(s) which would explain the use of the leaves of Globimetula braunii to "hasten delivery" in traditional medicine practice.