Inhibitory effects of essential oils on the growth of E. coli and S. aureus

BSC-Ursa Minor 85

Essential oils have antibacterial properties due to their high concentration of phenolic compounds. These compounds are found to induce apoptosis and inhibit cell proliferation and differentiation. Carvacrol in particular, attacks the cellular membrane, making it permeable to potassium ions and protons, thus acidifying the cytoplasm and inhibiting ATP production. Oregano oil is known to have carvacrol as a natural source of antioxidants. Moringa oleifera poses to have potential antioxidant, anticancer, anti-inflammatory, antidiabetic and antimicrobial properties. Maracuja oil stems from the genus Passiflora incarnata and is known to be rich in quercetin, which is the source of its acclaimed antioxidant, anti-inflammatory, and anticancer properties. We hypothesized that the growth of Escherichia coli (a gram-negative bacterium) and Staphylococcus aureus (a gram-positive bacterium) would show decreased growth in the presence of oregano, moringa, and maracuja essential oils. We grew both E.coli and S. aureus under high concentrations; 2% of oregano, maracuja, and moringa oils. We used a spectrophotometer as a proxy to measure cell growth over a 24 to 36-hour period. Our results showed that the oregano oil negatively affected the growth of E.coli and S. aureus. The moringa and maracuja oils have shown potential elements of inhibiting the bacterial growth, but a definitive result has not been obtained. Having documented the difference in cell growth of E. coli and S. aureus with these three essential oils, we would like to screen and test additional essential oils and investigate the effects of these oils on the cellular mechanism.