| dc.description.abstract | The use of plants to cure diseases and relieve physical sufferings started from the earliest times of mankind's history. In Africa, 80% of the population uses traditional medicine for primary health care. Due to antimicrobial resistance becoming a global problem with far reaching implications for the survival of human race, efforts are continuously made to overcome this. Current efforts include research in finding new and innovative antimicrobials from plants.
Participatory Rural Appraisal (PRA) method was used to identify plants used in management of diseases by 110 traditional medical practitioners in Machakos and Kitui districts. Voucher specimens were deposited at Department of Land Resource Management and Agricultural Technology (LARMAT), University of Nairobi for identification The two districts have a low doctor/patient ratio compounded with most hospitals being located in urban areas thus most of population seeks medical attention from TMP The minimum inhibitory concentration (MIC) of twelve (12) methanolic plant extracts were determined using standard cultures of Pseudomonas aeruginosa, Escherichia coli, Bacillus cereus and Micrococcus lutea. The data was stored in Microsoft Excel 2003°, and then analyzed using Genstat® (Version 9.0). Comparison was computed for the susceptibility of different bacterial species and considered statistically different at P<0.05.
Extracts of Harrisona abysssinica and Terminalia kilimandscharica showed activity against all bacterial strains. H. abyssinica showed inhibitory concentration against Pseudomonas aeruginosa at 37.5mg/ml. Ps aeruginosa was the least sensitive to the plant extracts with only 45% of plant extracts having inhibitory activity. Bacillus cereus was the most sensitive to the extracts with 83% of plant showing inhibitory activity and 64% had
MIC of less than 20mg/ml. The plant extracts were more active against Gram positive bacteria than Gram negatives. The positive controls showed significant inhibitory activity at concentration of less than Img/ml.
The bioactivity of the methanolic plant extracts was determined using the brine shrimp lethality test. The serial dilutions of 1000, 100 and lOpg/ml were made respectively. The percentage mortality was determined for each dilution and controls after 24 hours. The lethal concentration 50 (LC50) and 95% confidence intervals were determined using probit analysis.
The plant extract with the lowest LC50 value was the most toxic to brine shrimp nauplii while the one with highest LC50 value was the least toxic. All plant extracts showed significant bioactivity at LC50 <1000pg/ml except Ziziphus abyssinica which was the least toxic to brine shrimp with LC50 >1000pg/ml. Ajuga remota was lethal to brine shrimp nauplii at 61.6pg/ml. Twenty five percent (25%) of methanolic plant extracts under investigation showed lethality to brine shrimp at LCso^OOpg/ml.
The results of the present study support the continued use and further scientific validation of the selected medicinal plants by the herbalists in the management of infectious conditions. The plant extracts screened, A. remota showed the inhibitory concentration at less than 35mg/ml and also had the lowest LC50 less than 100 pg/ml, these results lend further support its traditional use. | en_US |
