The antifertility effect of crude extract of plumbago zeylanica in rats

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Plumbago zeylanica is a shrub that grows in many parts of tropical and some Asian countries. It is normally grown as ornamental plant, and in the wild found in maritime regions. Various parts of the plant are used ethno-medically to treat many ailments. In Ghana, the root decoction is use to treat piles, leprosy and as abortifacient. (Oliver Beaver, 1978) The present investigation is to test the hypothesis that administration of ethanolic crude extract of the root decoction of P. zeylanica to female Wistar rats would reveal any possible interference in the normal processes of the oestrus cycle, ovulation and implantation rate, teratogenlc and foetotoxic effect, as well as foetal development. The study also looks at the uterine stimulant activity of the extract, cytotoxicity using Brine shrimp; Artemia sauna, and the hormonal profile of the extract. Doses of the extract, equivalent by weight to normal adult human doses of 1 .0g/kg, 2.0 g/kg and 4.0 g/kg were administered orally to female rats in the study of the prenatal parameters. The median dose of 2.0 g/kg and a high of 4.0g/kg revealed a significant ova loss (P>0.05) when the extract was administered prior to and during pregnancy. There were no significant changes in the foetal weight, length, gait and stature. Neither were there any structural deformity in any of the maternal ovaries, uterus and the visceral organs. Thus the various doses of extract administered to the rats revealed no teratogenic and/or foetotoxic effect. The assessment of the uterine stimulant activity was performed on normal isolated uterine horns of pregnant and non-pregnant uterus primed with stilboesterol 24 hours before experimentation. Various doses of the extract, acetylcholine, nor- Adrenaline, and antagonist required to produce a contractile response were administered. The extract produced a dose-related contractile response as the standard spasmogens. However, the response was about 40% that of acetyicholine. The response produced by the extract and the acetylcholine were inhibited by atropine, but to a different extent. The study therefore revealed that, the root extract of P. zeylainca has muscarinic action, possibly by stimulating alpha-adrenoceptors in the rat uterus. In the study of the hormonal profile of the extract, oestrogenic & anti-oestrogenic, as well as the androgenic & anti-androgenic effect were considered. In the oestrogenic activity bioassay, 0.5 mg/kg of stilboestrol was administered intraperitoneally to immature female rat (25 — 30 days old) group, and extract doses of 2.0 g/kg and 4.0 g/kg were also administered orally to a second group. Concurrent administration of 0.5 mg/kg of stilboestrol (i.p.) and 2.0 g/kg of extract was administered (p.o). The study revealed that the extract possesses oestrogenic activity but is devoid of anti-antioestrogenic effect. The same process was considered for the assessment of the androgenic and anti-androgenic studies using testosterone and immature male rats (25-30) days old. The study showed that the extract is devoid of androgenic and anti-androgenic activity. The cytotoxicity test using Brine shrimp, Artemia sauna, revealed that, the extract possesses some significant levels of cytotoxicity. The study therefore confirms the traditional use of the plant as an abortifacient agent.
A Thesis Submitted to the school of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumaasi, in partial fulfilment of the requirements of the Degree of Master of Science (Reproductive Biology, 2000