Antimicrobial activity of some medicinal plants used by the Samburu community of Northen Kenya against selected bacterial and fungal pathogens.

Abstract
Medicinal plants form an integral social and cultural component, and sometimes the only alternative available treatment for health problems. Infectious diseases concern the whole world because they cause an estimated 98% of deaths in both children and adults in developing countries. The aim of the study is to determine ethnobotanical uses and the bioactivity of some medicinal plants used by the Samburu community against selected bacterial and fungal pathogens. This study evaluated both antibacterial and antifungal activity of the selected twenty two medicinal plants used by the Samburu community. An ethnobotanical survey was conducted and collected information from herbalists on their use in the treatment of various infectious diseases. Plants identification was done with assistant of a taxonomist from Kenyatta University. Voucher specimens were prepared and deposited at the Department of Plant Sciences herbarium. Methanolic plant extracts were screened using Kirby-Bauer disk diffusion technique against eleven strains of bacteria and fungi obtained from Centre for Microbiology Research at Kenya Medical Research Institute, Nairobi Kenya. They were either American Type Culture Collection (ATCC) or clinical isolates; Bacillus subtilis (clinical isolate), Staphylococcus aureus (ATCC 25923), Streptococcus pneumoniae (ATCC 28910), Escherichia coli (ATCC 25922), Vibrio cholerae (ATCC 27622), Shigella dysenteriae (ATCC 26988), Candida parapsilosis (ATCC 18310), Cryptococcus neoformans (ATCC 19310), Aspergillus jlavus (clinical isolate), Microsporum gypseum (clinical isolate), Trichophyton mentagrophyte (clinical isolate). Minimum inhibitory concentrations (MICs) were determined by measuring the diameter around the discs, while micro-dilution technique was used to determine the minimum bacteriocidal and fungicidal concentrations (MBCsIMFCs). Extracts of Acacia nilotica, Thylachium africanum and Loranthus acaciae produced high antibacterial and antifungal activity results of ~9-15 mm and 9.375 - 18.75 mg/ml as showed by the MICs and MBCslMFCs results. Screening for phytochemicals; tannins, saponins, flavonoids, cardiac glycosides, alkaloids, and terpenoids indicated presence at varying concentrations either high, moderate, low or absent. Significant difference of zones of inhibition means of all the strains was observed at P:S;0.05. Clear indications from the data obtained were that these plants extracts serve as an enormous source of untapped antimicrobial agents. This study recommended that the Samburu community should continuously be sensitized on sustainable use of medicinal plants and that they should give priority to domesticating the medicinal plants. Further studies on the biological properties, isolation and identification of active components in the plant parts used in this research in order to test specific antimicrobial activity was also recommended.
Description
Department of Microbiology, 140p. November 2014
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