ANTIFERTILITY PROPERTIES OF SELECTED KENYAN MEDICINAL

Abstract

It has been reported that many deaths occur in developing countries due to pregnancy related complications as well as during illegal abortions. The abortions are mainly due to unplanned pregnancies that can be avoided through use of birth control methods. People living in the rural areas of Kenya have poor access to conventional healthcare facilities and hence heavily rely on natural methods or medicinal plants extracts as birth control agents due to their affordability and accessibility. In addition, the affordable conventional contraceptives are associated with undesirable side effect. Medicinal plants are reported in folklore to play a role as contraceptives, but these claims and/or the mechanisms of action have not been demonstrated scientifically. Very few studies have been carried out to confirm the safety and efficacy of medicinal plants used as anti-fertility agents. The aim of this study was therefore to screen selected medicinal plant extracts for anti-fertility activity, effect on the oestrus cycle as well as on the weight of the ovaries and uterus in mouse model. The acute toxicity of the active extracts in mice was determined, as well as, the determination of the chemical profiles of the bioactive extracts. Extraction of Moringa oleifera (aerial, seed, root bark, twigs and stem bark), Terminalia brownii (stem bark), Ximenia americana (leaves, stem bark and root bark), Bridelia micrantha (aerial parts), Lippia kituensis (root), Rhoicissus revoilii (aerial parts and roots), and Ocimum masaiense (aerial parts and roots) parts was carried out using water, methanol, ethyl acetate, dichloromethane and petroleum ether. The extracts were then administered to mice at a dose of 800 mg/kg for anti-fertility experiment and in determination of their effect on ovary and uterus weight as well as oestrus cycle. Acute toxicity was tested by administering a dose of 0 to 5000 mg/kg orally. From the study, the extracts of the leaves of Bridelia micrantha, and Ximenia americana and the seeds of Moringa oleifera were shown to have reversible anti-fertility effect at a dose of 800 mg/kg when administered orally to female mice. The stem bark of Terminalia brownii had an irreversible anti-fertility effect at a dose of 800 mg/kg when administered orally. The study on the effect of the active extracts on the oestrus cycle exhibited an arrest of the normal oestrus cycle at either the diestrous or the proestrous phase. The presence of compounds such as steroids, terpenoids, alkaloids, saponins and flavonoids found in the bioactive extracts may have contributed to the anti-fertility activity. The bioactive extracts had no significant effects on the weight of both the ovaries and the uterus. The bioactive extracts did not show severe signs of toxicity at the highest concentration tested (5000 mg/kg) except Ximenia americana leaves extracts which had a mortality rate of 20% at 5000 mg/kg. The study provided several medicinal plant extracts that have potential to be developed into an alternative drug for birth control. The bioactive extracts may be taken for further analysis to determine their lowest effective doses as anti-fertility agents as well as their mechanisms of action.