Seven medicinal plant extracts traditionally used in Kenya, mainly for management of infectious conditions, were chosen and screened for their antibacterial activity against Gram-negative (
Pseudomonas aeruginosa
and
Escherichia coli
) and Gram-positive (
Bacillus cereus
and
Staphylococcus aureus
) bacteria. Antibacterial activity was tested using the broth dilution method.
Harrisonia abyssinica
and
Terminalia kilimandscharica
extracts showed significant activity against Gram+ and Gram- bacteria. The methanolic extracts of
T. kilimandscharica bark and
H. abyssinica bark and leaves showed minimum inhibitory activity against all tested bacteria, with minimal inhibitory concentrations ranging from 25-150 mg/mL.
Ajuga remota
and
Amaranthus hybridus
, which are lethal to brine shrimp nauplii, showed significantly lower antibacterial activity than those that were relatively non-toxic.