Ethnobotanical, Antioxidant And Toxicity Study Of Selected Medicinal Plants Used In Nyamira North Sub-county, Nyamira County

Abstract

Traditional medical practices are common with many Kenyan communities. There is a steady use of herbal remedies to treat diseases despite increased availability of conventional medicines. Therefore it is of paramount significance to document these plants as a means of preserving cultural knowledge of traditional medicine. The study aimed to identify and document all the plants used for oxidative stress-related diseases in the study area and also evaluate the antioxidant and toxic effects of some selected medicinal plants that are used by traditional medical practitioners (TMPs) in Nyamira County. Nyamira North Sub-county was the study area in which field study was carried out. Thirty six (36) TMPs were selected from the seven sub-county wards namely Bokeira, Magwagwa, Itibo, Ekerenyo, Bomwagamo, Kiabonyoru and Mekenene. The TMPs were interviewed using semi-structured questionnaires. Informational of the plants used (scientific name, local name, growth form, habitants, disease treated and the part used) was collected and documented. Four selected plants based on existing literature namely, Phragmanthera usuiensis, Ensete ventricosum, Echinops amplexicaulis and Rhoicissus tridentata, were screened for phytochemicals and subsequently subjected to toxicological studies to determine their safety Frequency tables and data triangulation was used to present the collected data. Fifty seven (57) medicinal plants species from 36 families and covering 53 genera were identified as being used in management of oxidative stress. Thirty nine plant species were found to have reports of similar use in literature whereas 18 species were being reported for the first time in regard to their use in oxidative stress-related diseases. The most common encountered families were Asteraceae (15.79 %) followed by Solanaceae (7.02%) and then Fabaceae and Rubiaceae each at 5.26%. Majority of the growth forms used were shrubs xiv (42%), followed by herbs (33%), trees (14%) and climbers (11%). The root/root barks were the parts of the plants that were used in greater percentage (53%) then the leaves (25%), stem bark (12%) and whole plant (8%). Phytochemicals analysis of the selected plants extracted using water and methanol showed presence of various bioactive compounds. The phytochemicals found in aqueous extracts were tannins, glycosides, saponins, flavonoids, phenols, coumarins and free sugars. Phytochemicals found in methanolic extracts include alkaloids, tannins, glycosides, saponins, steroids, flavonoids, terpenoids, phenols, coumarins and free sugars. Radical scavenging activities of the four plant extracts were evaluated using DPPH radical-scavenging method. At concentrations above the IC50, all methanolic extracts except in E. ventricosum extracts exhibited higher activity than the aqueous extracts. All groups of test animals did not exhibit any serious toxic or lethal effects even at the administration of the limit dose, 2000 mg/kg body weight.