| dc.description.abstract | lnfectious diseases are prevalent and Iife threatening in Kenya. The majority of the sick are
seeking herbal remedies in search of effective, safe, and affordable treatments. This study
investigated the antimicrobial activity and presence of alkaloids, terpenoids, sapogenins,
flavonoids and quinones in different parts of Vernonia glabra, Senna didymobotrya, and
Kigelia africana. Traditionally, these medicinal plants are used to treat microbial infections in
Kenya. The plants were selected based on the available traditional medical knowledge and
literature and collected in January 20 lOin Machakos and Kisumu counties. Diffcrent parts
were dried at room temperature under shade, ground into powder and extracted in
dichloromethane: methanol (1: 1) and water. The crude extracts were tested against
Staphylococcus aureus (gram positive), Escherichia coli (gram negative) bacteria, Candida
albicans (yeast fungus), and Aspergillus niger (filamentous fungus) for antimicrobial activity
and Minimum Inhibitory Concentrations (MICs) determined using disc diffusion technique
under sterile conditions. Discs impregnated with standard antibiotics (Streptomycin for
bacteria and Nystatin for fungi) were used as positive controls while the extraction solvents
were used as negative controls. Antimicrobial activity was determined by measuring the
diameter of the clear inhibition zones around the paper discs using a transparent ruler (ern)
after 24 to 48 hours for bacteria and yeast fungus, and up to 72 hours for f lamentous fungus.
Thin Layer Chromatography (TLC) was used to determine the chemical compounds present
in selected active crude extracts. Results showed that, organic extracts of V glabra leaf
(Mean inhibition zone of 1.85 em) and flower (MIZ of 1.78 ern) recorded the highest activity
against S. aureus than the standard antibiotic (Streptomycin MIZ of 1.30 em). Organic extract
of V glabra flower showed significant activity only against S. aureus, with the lowest MIC
of 1.5625 rng/I 00 ~I compared to streptomycin at high MIC of 6.25 mg/ 100 ul. Qual itative
spray reagents on TLC plates, showed the V glabra and S. didymobotrya flavonoids highly
present; terpenoids, sapogenins and quinones sufficiently present and V glabra flower
alkaloids greatly present. The results of this study suggest that the three plants have
significant antimicrobial properties and justify their use in traditional herbal medicine for the
management of microbial based diseases. The presence of chemical compounds in most
extracts of V glabra indicates its potential to produce novel compounds. Bioassay-guided
fractionations are recommended to identify the compounds responsible for antimicrobial
activity. Cytotoxicity assays are highly recommended for V glabra in order to verify,
validate and document its safety in medicine. | en |
