Efficacy of Medicinal Plants Used by Communities Around Lake Victoria Region and the Samburu Against Mycobacteria, Selecfed Bacteria and Candida Albicans

Abstract

In Africa more than 70% of the people refer to ethnomedicine for their health issues. With the emergence of new diseases and drug resistance to infections, traditional medicine should be given more attention in modern research and development. Tuberculosis (TB), a deadly infectious disease that annually kills about 3 million people worldwide is complicated. This is due to significant toxicity, emergence of multidrug resistant TB (MDR-TB) and extensively drug resistant TB (XDR- TB) and lengthy therapy which creates poor patient compliance. There is also a major therapeutic problem due to emergence of Escherichia coli, Klebsiella pneumoniae and other Blactamase producers. Diarrhoeal diseases are responsible for 4.6 million deaths every year. These highlight the need to develop novel drugs. Natural products provide unlimited opportunities for new drug leads because of the unmatched chemical diversity. This study evaluated the antimicrobial potential of 34 medicinal plants used by communities living around the Lake Victoria region and the Samburu Community of northern Kenya, following an ethnobotanical survey. Plants were collected and identified at the Department of Pharmacy and Complimentary Alternative Medicine, Kenyatta University, Nairobi, Kenya; in whose herbarium voucher specimens were deposited. Methanolic extracts from plants were tested against four strains of Mycobacteria (Mycobacteria tuberculosis, M. kansasii, M. fortuitum, and M. smegmatis) obtained from Kenya Medical Research Institute (KEMRI), Nairobi, Kenya. BACTEC MGIT 960 system was used. Salmonella typhi (clinical isolate), Klebsiella pneumoniae (clinical isolate), Pseudomonas aeruginosa (ATCC 25852), Escherichia coli (ATCC 25922) Staphylococcus aureus (ATCC 20591) and Candida albicans (ATCC EK138), obtained from Kenyatta National Hospital in Nairobi, Kenya, were also screened against using standard procedures. The crude extracts were analyzed for presence of phytochemicals. Croton macrostachyus, Vernonia amygdalina, Toddalia asiatica, Aloe secundiflora, Cordia sinensis, and Euphorbia scarlatina gave strong antimycobacterial activity (zero GUs) against M. kansasii, at all concentrations used. Entada abysinnica, T. asiatica, Salvadora persica, C. sinensis, Scadoxus multiflorus and E. scarlatina extracts were active (zero GUs) against M. tuberculosis. Extracts from Carissa edulis, V. amygdalina, A. secundiora, Pistacia aethiopica, S persica, S. multiflorus, E. scarlatina, and Acacia nilotica were active (zero GUs) against M. fortuitum. Against M. smegmatis, Carissa edulis, V. amygdalina, A. secundiora, S. persica, S. multiflorus, E. scarlatina and A. nilotica were active (zero GUs). Eurphobia scarlatina was active (Zero GUs) against all the strains of mycobacteria. There was significant difference of the means of the zones of inhibition of the S. typhi, K. pneumoniae, P. aeruginosa, E. coli, S aureus and C. albicans at P< 0.05. The MICs and the MBCs of the extracts were determined by use of microtitre plate method with E. abysinnica, T. asiatica, Thylachium africanum, A. secundflora, A. nilotica and Momordica charantia extracts showing good activity with MICS and MBCS of 4.687- 18.75 mg/ml in some test cultures. Klebsiella pneumoniae and C. albicans were mostly insensitive to extracts. Preliminary phytochemistry identified six phytochemicals to which tannins were common in most plant extracts. The data suggests that plant extracts could be a rich source of antimicrobial agents. Results also provide an indication of merit in their ethnomedicinal use