In vitro Evaluation of Spectrum of Antimicrobial Activities of Leaves and Stem Bark Extracts of Alchornea cordifolia against Some Pathogenic Clinical Isolates from University of Uyo Medical Centre

Abstract

Antimicrobial activities of the leaves and stem bark in aqueouse and ethanol extracts of Alchornea cordifolia were evaluated using tube dilution assay to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) and Minimum Fungicidal Concentration (MFC) of the plant parts and to determine spectrum of activities considering the antimicrobial effect on Gram positive, Gram negative and yeast (Candida albicans), these organisms are known to be pathogenic in nature. Results showed leaves extracts, both aqueouse and ethanol exerted higher activities than the stem bark extracts with MIC values ranging from 1.95 mg/mL – 15.63 mg/mL, although the stem bark extract exhibited good inhibitory activities as well with MIC values ranging from 3.91 mg/mL – 62.50 mg/mL. The antimicrobial spectrum of activities against the organisms was determined by the ratio (R) of MBC/MIC. The leaf extract is bactericidal against the Gram-positive and Gram negative organism with the exception of E. coli that MBC was not determined and, fungicidal against Candida albicans with (R) MBC/MIC ≤ 2. The stem bark extracts were bactericidal against all the Gram positive organisms but bacteriostatic against Salmonella spp and fungistatic against Candida albicans with (R) MBC/MIC ≥ 2. This study revealed that the aqueous and ethanol extracts of leaf and stem bark of A. cordifolia plant exhibited strong antibacterial activities on Staphylococcus aureus, Streptococcus pneumoniae, Bacillus Subtilis, (Gram positive), Escherichia coli, Pseudomonas aeruginosa, Salmonella spp (Gram negative) and also exhibit anti-fungal activity against the Candida albicans. The leaf extract exhibited broad antimicrobial spectrum with bactericidal activities against Gram positive, Gram negative and yeast (Candida albicans).