<i>In Vitro</i> Evaluation of Ethanolic and Aqueous Crude Extracts of <i>Newbouldia laevis</i> Leaves on Bacterial Isolates from Ear Infections

Abstract

Abstract. The antibacterial effects of ethanolic and aqueous crude extract of leaves of Newbouldia laevis were evaluated against pathogenic Staphylococcus aureus, Staphylococcus epidermidis, Bacillus spp, Pseudomonas aeruginosa and Escherichia coli isolated from ear infections. A concentration gradient of the ethanolic and aqueous extract (12.5 mg/ml -100 mg/ml) was prepared and its effectiveness was tested by agar well diffusion method and nutrient broth dilution technique. The organisms tested varied in pattern of susceptibility but were more sensitive at high concentrations. The zone of inhibition of aqueous extract of Newbouldia laevis on test organisms ranged from 4.0 to 15 mm while the ethanolic extracts of Newbouldia laevis on test organisms ranged from 6.5 to 21.00 mm. The comparative susceptibility of test bacteria to Newbouldia and ciprofloxacin showed that there was a significant difference in the antibacterial activity of leaf extract and the antibiotic standard. The MIC values ranged from 12.5 mg/ml to 25 mg/ml. The extract showed a higher antibacterial activity against E. coli, Bacillus spp and S. epidermidis. The result of the study suggests that the leaf extract of N. laevis has the potential and could be used as a source for new broad spectrum antibiotics to treat ear infections caused by test organisms.