Ten Nigerian plants suggested from their ethnomedical uses to possess antimicrobial and antioxidant activities were studied for their anti-microbial and anti-oxidant properties. Antimicrobial activity was tested against
Escherichia coli
NCTC 10418,
Pseudomonas aeruginosa
,
Staphylococcus aureus
,
Bacillus subtilis
,
Candida albicans
,
Candida pseudotropicalis
and
Trichophyton rubrum
(clinical isolate).
Trichilia heudelotti
leaf extract showed both antibacterial and antifungal activities and was the most active against all the strains of bacteria tested.
Boerhavia diffusa
,
Markhamia tomentosa
and
T. heudelotti leaf extracts inhibited the gram negative bacteria
E.coli and
P. aeruginosa strains whereas those of
M. tomentosa,
T. heudelotti and
Sphenoceutrum jollyamum
root inhibited at least one of the fungi tested. At a concentration of 312 μg/ml, hexane and chloroform fractions of
T. heudelotti extract inhibited 6 and 14% of the fifty mult-idrug resistant bacteria isolates from clinical infectins, respectively.At ≤ 5mg/ml, the CHCl
3 (64%) and aqueous (22%) fractions of
T. heudelotti and those of CHCl
3 (34%) and EtOAC (48%) of
M. tomentosa gave the highest inhibition that wasstronger than their corresponding methanol extracts. The corresponding EC
50 of the extracts on
M. acuminata, T. heudelotti, E. senegalensis and
M. tomentosa were 4.00, 6.50, 13.33, and 16.50 ig/ml using the TLC staining and 1,1-dipheyl-2-picry-hydrazyl (DPPH) free radical scavenging assay. Therefore, leaf extracts of
M. tomentosa and
T. heudelotti, especially the latter, possess strong antimicrobial and antioxidant activities and should be further investigated. These activities justified the ethnomedical uses of these plants.
