Comparative Analyses of the Efficacy of Dry and Fresh <i>Mangifera indica</i> Ethanolic Extracts on <i>E. coli</i> and <i>S. aureus</i>

Abstract

Background: The need to identify and characterize new antimicrobial agents is important due to the increasing development of resistance by microorganisms to the existing antimicrobial agents. Aim: This study examined the efficacies of Mangifera indica on Escherichia coli and Staphylococcus aureus. Method: Three parts (leaf [L], root [R], and bark [B]) of the plant were analyzed. The extraction of the samples was performed by aseptically grinding the samples, dissolving in absolute ethanol, and filtering through whatman filter paper. The efficacy of the extracts bothsingle and combined was determined using agar well diffusion assay with gentamycin [10 μl] (E. coli) and vancomycin [30 μl] (S. aureus) as control antibiotics. Results: The higher concentration (C2 = 3.0 g/ml) showed more antibacterial effectiveness than the lower concentration (C1 = 1.5 g/ml) against both bacterial isolates with significant differences (P E. coli dry leaf extract; fresh bark extract), double extracts (S. aureus: dry and fresh leaf extracts) and triple extract (E. coli and S. aureus dry extracts). For the single extracts the bacteria has the following significant results: E. coli L (dry 6.3 ± 2.5 mm, fresh 14.7 ± 0.6 mm, P = 0.0050), R (dry 11.3 ± 1.5 mm, fresh 7.3 ± 1.5 mm, P = 0.0327); for S. aureus L (dry 7.0 ± 1.7 mm, fresh 11.0 ± 1.0 mm, P = 0.0257), R (dry 7.0 ± 2.0 mm, fresh 11.7 ± 1.5 mm, P = 0.0325), and B (dry 5.0 ± 1.0 mm, fresh 16.0 ± 1.0 mm, P = 0.0002). For the double extracts the bacteria has the following significant results: E. coli L + R (dry 15.7 ± 2.3 mm, fresh 1.7 ± 1.5 mm, P = 0.0070), R + B (dry 18.7 ± 1.5 mm, fresh 9.7 ± 1.5 mm, P = 0.0020), and L + B (dry 9.7 ± 1.5 mm, fresh 6.3 ± 0.6 mm, P = 0.0241); S. aureus L + R (dry 14.7 ± 1.5 mm, fresh 7.0 ± 1.0 mm, P = 0.0019), R + B (dry 15.3 ± 1.5 mm, fresh 11.7 ± 1.5 mm, P = 0.0424). For the triple extracts, the fresh leaves showed significantly higher levels of efficacy than the dry for both E. coli L + R + B (P = 0.0101) and S. aureus (P = 0.0307). The fresh extracts showed higher levels of efficacy than dry extracts against both bacteria for all the single and three combined conditions. Conclusions: Fresh extracts show better efficacies against E. coli while dry extracts show greater efficacies against S. aureus for both single and triple combined extracts. The reverse is true for double combined extracts.