Antimicrobial Studies of Aqueous and Ethanolic Extracts of Enantia chlorantha Leaves and Stem Bark and Their Combined Effect on Selected Bacteria and Fungi

Abstract

Aim: To revalidate the antimicrobial effects of aqueous and ethanolic extracts of Enantia chlorantha leaves and stem bark against Enterococcus faecalis, Escherichia coli, Salmonella Typhi, Shigella sonnei, Staphylococcus aureus, Proteus vulgaris and Candida albicans; and to check the effects on the isolates when the stem bark and leave extracts are combined. Place and Duration of Study: Department of Biotechnology, School of Science, Federal University of Technology Owerri, Nigeria, between January 2013 and May 2013. Methodology: Agar well diffusion method was used for the susceptibility studies while the Minimum Inhibitory Concentrations were determined using the broth dilution method. The Minimum bactericidal/fungicidal concentration was determined by plating on nutrient agar. Results: The ethanolic extract of E. chlorantha stem bark showed antimicrobial activity on all 7 isolates tested with zones of inhibition in the range of 5mm to 33mm, while its aqueous extracts showed activity on only 3 of the 7 isolates with diameter zones of inhibition ranging between 5mm to 20mm. The aqueous leaf extracts showed activity against 3 of the 7 isolates while the ethanolic extracts had activity on 6.  The minimum inhibitory concentration (MIC) of the ethanolic extract of both stem bark and leaves was between 1.56 and 12.5mg/ml, while that of aqueous extracts ranged from 6.25 to 12.5mg/ml. There was no obvious difference in the activity of the extracts when combined.  Conclusion: This study validates potent antimicrobial activity of ethanol and aqueous extracts of Enantia chlorantha leaves and stem bark in line with similar studies. Further work is however needed to determine the toxicity of the plant extracts and also identify active components of the plant.