Susceptibility of Proteus mirabilis, Staphylococcus aureus and Candida albicans to Extracts of Cola acuminata

Abstract

Ethanolic extract of the seed of Cola acuminata was evaluated for its antimicrobial and antifungal
activities as compared to standard anti-microbial agents using Proteus mirabilis, Staphylococcus aureus
and Candida albicans following standard microbiological procedures. Phytochemical screening of the
seed extracts reveals abundance presence of Tannins, Cardiac glycosides, flavonoids and Phlobatanins
and moderate presence of Alkaloids with a total absence of Saponins. At 25mg/ml, 50mg/ml, 100mg/ml,
200mg/ml and 400mg/ml concentrations of the extract used, Staphylococcus aureus and Candida
albicans were susceptible to all except the later which was resistant to 25mg/ml concentration. Proteus
mirabilis was resistant to all concentrations of the extract employed. Staphylococcus aureus was
susceptible to vancomycin (30µg) yielding 18mm zone of inhibition as compared to the seed extract
(20mm). Proteus mirabilis was susceptible to 10µg of Gentamycin (16mm), while Candida albicans was
susceptible to Clotrimazole (50µg) yielding 17 mm zone of inhibition as compared to the seed extract
(20mm). The Minimum inhibitory concentration of the extract was 50mg/ml and 25mg/ml for
Staphylococcus aureus and Candida albicans respectively. This study shows that ethanolic extract of
Cola acuminata is a superior antimicrobial agent against Staphylococcus aureus and Candida albicans,
but not for Proteus mirabilis as compared to the drugs evaluated.