OXYTOCIC EFFECTS OF THE AQUEOUS LEAF EXTRACT OF COSTUS LUCANUSIANUS – FAMILY COSTACEAE ON ISOLATED NON-PREGNANT RAT UTERUS

Abstract

Costus lucanusianus J. Braun (Costaceae) is a climbing herb, found mainly in the Niger Delta region of Nigeria. This plant is locally used in situations of pains, inflammation, dysmenorrhoea and in pyrexia. The purpose of this study was to investigate this claim with view to validating scientifically the ethno-medicinal usage. The aqueous extract was subjected to pharmacological testing in vitro on a piece of isolated rat uterus previously pretreated with 1 mg/kg stilbestrol for 24 h. The dose response curves of oxytocin and that of the extract were first obtained. The effects of antagonists like atropine (1 mg) and salbutamol (2 µg) on the dose response curve of the extract were also investigated. Possible synergy was investigated via co-administration of the extract and oxytocin. Finally the proximate analysis of the extract was investigated. The aqueous extract of C. lucanusianus and oxytocin both produced a dose dependent contraction of the uterus. An effect of 0.63±0.06 g force of uterine contraction produced by 12.5 mg of the extract was increased to 1.37±0.09 g when 200 mg of the extract was administered. Oxytocin at 0.16 i.u was observed to produce a similar force of contraction with 200 mg of the aqueous extract. Synergy was established as co administration of the extract at 200 mg and oxytocin at 0.08i.u, produced higher contractile effect, significantly higher (p<0.05) than when either the extract (200mg) or oxytocin (0.08 i.u) was administered alone. Both atropine and salbutamol significantly (p<0.0001) inhibited the contractile effect produced by the extract. The inhibitory effect showed by atropine on the contractile effect of the extract seems to suggest the involvement of muscarinic receptors. The proximate analysis carried out in this study is used to establish the identity of the crude drug sample. A moisture content of 10.047 % was obtained. The total ash is a measure of the non-volatile inorganic constituents remaining after ashing. The values of 3.42 % were obtained.