Antimicrobial Activity of Fruit Extracts of Xylopia Aethiopica and its Combination with Antibiotics against Clinical Bacterial Pathogens

Abstract

The in- vitro antimicrobial activity of ethanol and aqueous fruit extracts of Xylopia aethiopica, four conventional antibiotics: gentamycin, ampicillin erythromycin and ciprofloxacin and the combination of each extract with the conventional antibiotics were investigated using the agar diffusion method.  Clinically isolated strains of bacteria: Pseudomonas aeruginosa, Klebsiella pneumoniae, Escherichia coli, Bacillus subtilis,  Staphylococcus aureus Streptococcus faecalis and Shigella dysenteriae were used for the assay. The preliminary screening of phytochemical constituents of the fruits of Xylopia aethiopica showed the presence of cardiac glycosides flavonoids, phlobatannins, tannins, phenol, anthraquinones, saponin and steroids. The  ethanol extract was active against P. aeruginosa, B. subtilis, S. aureus,  but showed no activity against K. pneumoniae and  E. coli while the aqueous extract was only active against S.aureus. The test organisms showed susceptibility to the antibiotics used except P. aureginosa which was resistant to ampicillin. Synergism was obtained in 39.3% of   all the combinations investigated, antagonism  in 57.1%, and indifference  in 3.6%  Gentamycin when combined with the aqueous and ethanol extracts had the highest percentage of synergism, Caution should be taken in with concurrent administration of X.aethiopica with  conventional antibiotics  because of the higher percentage of antagonism observed.

KEYWORDS: Xylopia aethiopica, antibiotics, plant extract antimicrobial activity, synergism, antagonjsm.