Antimicrobial Activity of Methanolic and Aqueous Extract of Rhodomyrtus tomentosa Leaves against Staphylococcus aureus and Escherichia coli

Abstract

Food poisoning is one of the riskiest illnesses caused by an organism like bacteria, viruses and parasites, which can contaminate food at any stage of food production. Most reports are associated with bacterial contamination through the food preparation process. Researcher nowadays attempts to discover a safer agent to use in food preparation as a food preservative agent. Thus, the potential of Rhodomyrtus tomentosa leaves as an antimicrobial agent was explored in this study. It was tested against two bacteria which are Staphylococcus aureus (gram-positive) and Eschericia coli (gram-negative). Antimicrobial activity of methanol and aqueous R. tomentosa leaves extract was compared using gram staining, bacterial identification, antimicrobial sensitivity testing (AST), minimal inhibitory concentration (MIC), minimal bactericidal concentration (MBC) and statistical analysis. The disc diffusion technique was used for AST where the mean area of inhibition methanol and aqueous extract against S. aureus was 18 mm and 16 mm respectively, whereas there was no area of inhibition for E. coli. MIC was done to determine the minimum concentration of the extract needed to inhibit the bacteria. After that, MBC was performed to confirm the previous MIC result. Statistical analysis was done by conduct it through SPSS software program. Then, the result for S. aureus is obtained from finding its p-value. Statistically, a significant difference between the two bacteria was analyzed by using independent t-test. A result of p-value less than 0.05 was considered significantly different as one another. Statistical analysis showed no significant difference between methanol and aqueous extract on antimicrobial activity. In conclusion, both aqueous and methanol leaves R. tomentosa yielded similar antibacterial activity which susceptible to S. aureus and can be used safely toward foodborne pathogen.