Effects of Kenyan Grewia tenax (Mukawa Wa Guba) Root Extract on Female Wistar Albino Rats’ Estrus Cycle and Reproductive Hormones

Abstract

Globally, infertility is estimated to be 8-12 percent of couples within the childbearing years, while in Kenya it is at 11.9 per cent. In ethnobotanical studies in Kenya and India, Grewia tenax, a shrub (Fam. Teliaceae), has been reported to be used as a pro-fertility herb. The main objective of this research was to determine the effects of Kenyan Grewia tenax root extract on female Wistar albino rats’ ovarian cycle and reproductive hormones.The specific objectives of the study were to determine the phytochemical constituents of Kenyan Grewia tenax root extract and its acute oral toxicity. The study was also determined the extracts’ effects on the female Wistar albino rat's estrus cycle and reproductive hormone profile. The study used 30 female Wistar albino rats with established regular estrus weighing 160 – 200 grams. The study was undertaken in 27 consecutive days with the first 10 days being for checking to ensure regular estrous cycle via daily vaginal smears. Regular estrus cycles were disrupted using norethisterone for seven days. In the last 10 days the animals were randomly divided into three groups: Group I; (negative control) administered with normal saline, Group II (test group) divided into three subgroups of 250, 500 and 1000 mg/kg extract administration Group III (positive control), administered with 0.83mg/kg body weight clomiphene. Blood for reproductive hormones analysis was collected daily from each rat tail and put on a slide with silver paste for Raman spectroscopy analysis. Results were analyzed using SPSS, and the means compared using one-way ANOVA followed by Tukey HSD post hoc t-test, p-value <0.05 was considered statistically significant. Data was presented in graphs and charts. Preliminary phytochemistry of the extract revealed the presence of alkaloids, flavonoids, saponins, sterols, terpenes and cardiac glycosides. There were no adverse effects at 5000 mg/kg extract on oral administration. The study showed significant restoration of the estrus cycle at 250, 500 and 1000mg/kg administration of Grewia tenax in comparison to the negative control. The frequency of estrus cycle had a significant increase in proestrus phase (P=0.001) and estrus phase (P=<0.001) with subsequent decrease in metestrus (P=<0.001) and diestrus (p=0.001). Grewia tenax methanolic root extract caused an increase in reproductive hormone intensity in a dose depended manner. This study concludes that Grewia tenax has fertility-enhancing potential due to its ability to regularize disrupted estrus cycles and raise the intensity of reproductive hormones in rats. The study recommends Grewia tenax phytochemical compounds isolation and characterization. Subacute and chronic oral toxicity studies should also be undertaken to establish the safety of Grewia tenaxadministration over a more extended period. The species requires further investigation to establish its effects on reproductive hormone receptors.