The antimicrobial effects of Murraya koenigii leaves extract against foodborne pathogens

Foodborne disease is a significant public health problem caused by ingesting foods or beverages contaminated with foodborne pathogens. Murraya koenigii (M. koenigii) or "daun kari" is an important medicinal plant belonging to Rutaceae family that has been traditionally and widely used as medicinal herbs. This study was conducted to determine the antimicrobial effects of M. koenigii against selected foodborne pathogenic bacterial isolates. Thus, a broader recognition of herbal medicines as therapeutically useful could be adapted. The methanol and aqueous extraction of M. koenigii leaves were prepared to test the antimicrobial effects against selected foodborne pathogens ( Staphylococcus aureus, Escherichia coli and Salmonella enterica serovar Typhi by disc diffusion method at a concentration of 100 mg/mL of the extract. Bacteria that produced an inhibition zone at 100 mg/mL Staphylococcus aureus ( S. aureus) were further tested for the minimum inhibitory concentration (MIC). The inhibition zone produced was measured and compared with commercial antibiotics. Only Gram-positive bacteria, S. aureus was found to be susceptible as compared to Gram-negative bacteria. The extract showed an antimicrobial effect by producing inhibition activity against S. aureus. The S. aureus was significantly inhibited by the extracts even in low MIC (1.56 mm), while E. coli and S. enterica serovar Typhi were found to be completely resistant. The methanol extract was found to be more effective compared to the aqueous extract. In conclusion, M. koenigii leaves methanol extract exhibit an antimicrobial effect, particularly on S. aureus and could be interesting information in designing a potential antibacterial agent against foodborne pathogens.