| dc.description.abstract | In Kenya, microbial diseases are prevalent and life threatening. Currently, herbal remedies are of
interest as considered to be easily available, safe, effective and affordable. This study was
designed to investigate antimicrobial activity, toxicity and phytochemical composotion in crude
extracts of Leucas calostachys, Mimusops kummel, Acacia lahai and Caesalpinia decapetala.
These plants are majorly used by herbalist from Sotik Sub- County, Kenya for treatment of
gastroinstestinal problems. Antimicrobial activity was investigated using disc diffusion method
and data analyzed using ANOVA. Minimum inhibitory concentrations (MIC) were determined
by broth dilution method. Microorganisms employed were methicillin resistant Staphylococcus
aureus, Bacillus cereus, Escherichia coli, Pseudomonas aeruginosa and Candida albicans.
Extracts toxicity was investigated using brine shrimp lethality assay, LD-50 was determined by
analysis of data using Finney’s computer program. Phytochemical screening for flavonoids,
alkaloids, saponins and sesquiterpene lactones was determined using Thin layer Chromatography
(TLC). Highest antibacterial activity was noted with methanol extract of A. lahai on B. cereus
while acetone extracts of A. lahai exhibited the highest antifungal activity. Most active crude
extracts had MICS values of 20mg/ml. All the tested extracts had LC50 values greater than 1000
μg/ml hence non-toxic on Artemia salina larvae. Flavonoids, alkaloids and saponins were present
in all the plant species tested. Sesquiterpene lactones were present in L.calostachy and M.
kummel. The results of this study shows that the tested plants have antimicrobial effects and is
non-toxic supporting their traditional usage for treatment of microbial infections. Further
bioassay of isolated compounds from active crude extracts is recommended.
Key words: Antimicrobial activity, Brine shrimp lethality assay, Medicinal plants,
Phytochemical composition, Sotik Sub- County; Kenya. | en_US |
