UTEROTONIC PROPERTIES OF THE METHANOL EXTRACT OF MONECHMA-CILIATUM

The oxytocic activity of the hot methanol extract (HME) of the leaves of Monechma ciliatum was compared with other uterine stimulants like e rgometrine, oxytocin, 5-hydroxytryptamine (5-HT), acetylcholine (ACh) and prostaglandins (PGs) E-2 and F(2)alpha (PGE(2) and PGF(2)alpha) in the presence of some antagonists in an attempt to explain the mechani sm of action of the extract. The effects of the reference drugs on ute ri isolated from rats pretreated with HME for 2 weeks were also observ ed. Atropine blocked the effect of ACh and partially blocked those of HME while L-366-948 blocked only the effect of oxytocin. Indomethacin inhibited the effects of HME as well as all the other drugs, except th e PGs and ACh. D-600 blocked the effect of all the drugs including HME . Methysergide antagonised only the effect of 5-HT and partially block ed ergometrine. Prolonged treatment altered the uterine musculature an d the activity profile of the reference drugs. These results suggest t hat the HME may be acting by more than one mechanism to contract the u terus and explains the mechanism of the anti-implantation activity of the plant. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.