The Effects of Aqueous Leaf Extracts of Hybanthus Enneaspermus and Parquetina Nigrescens on Female Reproduction and Pregnancy Outcome in Sprague-Dawley Rats

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Awobajo, F.O
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There is dearth of scientific information on the effects of Hybanthus enneaspermus (HE) and Parquetina nigrescens (PN) on female reproduction, pregnancy and its outcome. Yet, these two medicinal plants remain the first line of medicinal plants commonly used by Traditional Birth Attendants in care of women before, during and after pregnancy in South-west Nigeria. The effect of aqueous leaf extract of Hybanthus enneaspermus (HEaq) and Parquetina nigrescens (PNaq) on female reproduction and pregnancy outcome were investigated using Sprague-Dawley rats. The acute oral lethal doses (LD50) for the two extracts were determined in Swiss albino mice, using moving average method and probit analysis. Extract administration was orally at a dose of 2g/kg body weight for four weeks for non-pregnant rats and for the duration of pregnancy in gravid rats. The effects of the two medicinal plants were separately examined on gravid and non-gravid female reproductive parameters. Parameters examined in non-pregnant rats include; oestrus cycle pattern and length, ovulation, female hormonal profile (follicle stimulating hormone (FSH), luteinizing hormone (LH), estrogen and progesterone), reproductive and other organ weight (uterus, pituitary gland, ovary, liver and kidney) , organ histology and body weight changes. The effects of the two extracts were also examined on the following parameters in pregnant-rats; maternal body weight, uterine muscle contraction, blastocyst implantation, placenta weight, haematological profile, fasting blood glucose, lipid and electrolyte profile, blood pressure, gestation length, litter size, weight at birth, and the presence of any birth defect. The LD50 value of 8.23 ± 0.35 gram/kg body weight for HEaq and 13.93 ± 0.10 gram/kg body weight for PNaq was calculated using probit analysis. Oestrous cycle was studied prior to and after extract administration by daily examination of the vagina smears under the microscope. xx Blood samples were collected after 12 hours fasting, at the different phases of the oestrous cycle via retro-orbital sinus or via cardiac puncture after cervical dislocation for haematological, lipid, electrolyte and hormonal study. Ovulation study was carried out at estrus by flushing the oviduct with normal saline and counting the ovum in the effluent under the microscope. Certified pregnant rats grouped into the HEaq and PNaq extract treated groups were gavaged the corresponding extracts from day one till the day 19 of pregnancy for implantation/ resorption study or a day prior to delivery day. Laparotomy was carried out on day 19 of pregnancy after cervical dislocation, and the uterus examined for implantation sites and resorption sites that are vascularised areas without implantation. Dose-response of the two extracts at graded concentrations was examined on fasting blood glucose level in non-pregnant rats to determine their effective hypoglycaemic doses (EHD). The effective hypoglycaemic doses were subjected to oral glucose tolerance test and compared with standard known hypoglycaemic agent (Glibenclamide). Further studies on the hypoglycaemic effects of the two extracts at a dose of 2g/kg body weight were also tested in pregnant rats. The LD50 for the two extracts was determined using probit after oral injection of doses ranging between 2.5 - 20 gram/kg body weight for PNaq extract and 4 – 32gram/kg body weight for HEaq extract. The two extracts were found to have a wide LD50 margin producing no significant disruption of the liver tissue architecture thoug the weights were increased. However, an amorphous deposit was noticed in the glomerulus. The two extracts significantly increased (p<0.05) the estrogen and FSH level at all phases of the oestrous cycle. The two extracts also increased the length of the fertile period (proestrus and estrous). This was because of the reduced LH level recorded at the proestrus and estrus phases of the cycle. The reduced LH also resulted in reduction in the number of ovum released at ovulation with resultant increase in number of atretic follicles as revealed by the histological study of the ovaries. Contrary to their use in folkloric medicine, the two extracts had no significant effect on maternal red blood cell count. However, Hybanthus enneaspermus increased while Parquetina nigrescens reduced the white blood cell count. Both extracts increased significantly (p < 0.05) the spontaneous isometric contraction of the myometrial tissue. There was a significant reduction (p < 0.05) in the number of implants in extract treated rats while the placenta weights, weights and size of the litter at 19th day and at birth were also significantly reduced in all extract treated groups. The two extract have no effect on maternal weight gain during pregnancy but the wet weight of important organ such as pituitary responsible for secretion of gonadotrophins was significantly reduced after extract administration. The two extracts had hypoglycaemic activities and hypotensive effect in pregnant rats. Although, the mechanism of action of aqueous leaf extract of Hybanthus enneaspermus and Parquetina nigrescens on female reproduction and pregnancy is not fully known, it can however be concluded that the extracts possess anti-fertility effect in female rats. This anti-fertility effect was expressed via the down regulation of the luteinizing hormone released. The two extract also possessed hypoglycaemic and hypotensive activities that can justify their use in correcting some pregnancy associated diseases such as preeclampsia and foetal macrosomia. In addition, both extracts increased the contraction of the myometrial strips from pregnant rats justifying their possible use in inducing labour when given to pregnant women towards term.
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos
Hybanthus enneaspermus , Parquetina nigrescens , Female reproduction , Medicinal Plants , Research Subject Categories::MEDICINE::Physiology and pharmacology::Physiology
Awobajo, F.O (2010). The Effects of Aqueous Leaf Extracts of Hybanthus Enneaspermus and Parquetina Nigrescens on Female Reproduction and Pregnancy Outcome in Sprague-Dawley Rats. A Thesis Submitted to University of Lagos School of Postgraduate Studies Phd Thesis and Dissertation, 184pp.