Antimicrobial Activity of Aqueous and Ethanolic Extracts of Acacia nilotica Fruits and Myrrh on Bacteria Isolated from Wound Infections

Abstract

Acacia nilotica belongs to family Fabaceae of genus Acacia while Myrrh is a natural gum or resin extracted from a number of tree species of genus Commiphora. They are important medicinal plants possess antimicrobial activities. This research aimed to provide information about the antimicrobial activity of aqueous and ethanolic extracts of Acacia nilotica and Myrrh on bacteria isolated from wound infections. A total of fifty-six wound swab bacterial isolates were re-identified and tested for their antibacterial susceptibility against chosen commercial antibiotics; Amoxicillin/Clavulanic acid, Ciprofloxacin, and Erythromycin, and 100mg/ml aqueous and ethanolic extracts of Acacia nilotica and Myrrh using Kirby-Bauer disc diffusion method and Cup-plate method respectively. Data was analyzed using the Statistical Package for the Social Sciences (SPSS) program. Bacterial isolates were 15(26.8%)Klebsiella pneumonia, 12(21.4%)Staphylococcus aureus, 11(19.6%)Pseudomonas aeruginosa, 8(14.3%)Escherichia coli, 7(12.5%)Proteus mirabilis, and 3(5.4%)Enterococcus faecalis. It showed varied susceptibility to antibiotics. Both aqueous and ethanolic extracts of Myrrh showed no antibacterial activity (0 mm) for all isolated bacteria. One hundred mg/ml of Acacia nilotica ethanolic extract showed minimum inhibitory zones of 0mm and maximum of 23mm with mean ranged from 11.5-16mm for all isolates while aqueous extracts figures were 0-20mm with mean ranged from 12.08-14.57mm. Inhibitory effect of 100 mg/ml Acacia nilotica water extract showed statistical significant difference with Staphylococcus aureus and Pseudomonas aeruginosa with P-value of (0.012) and (0.047) respectively. This study concluded that 100 mg/ml Myrrh extracts has no antibacterial activity while 100 mg/ml Acacia nilotica fruits ethanolic and aqueous extracts showed good activity against all bacterial isolates except for S.aureus that showed resistance to the ethanolic extract. Water extraction for Acacia nilotica fruits proved to be more effective than ethanol extraction in case of S.aureus and P.aeruginosa isolates.