Synergistic effect of starch and royal jelly against Staphylococcus aureus and Escherichia coli.

OBJECTIVES To evaluate the synergistic action of starch on the antibacterial activity of royal jelly (RJ), a comparative method of adding RJ with and without starch to culture media was used. METHODS Strains of Staphylococcus aureus and Escherichia coli have been used to determine the minimum inhibitory concentration (MIC) of a variety of freshly reaped RJ. In a second step, lower concentrations of RJ than the MIC were incubated with a set of concentrations of starch and then were added to media to determine the minimum synergistic inhibitory concentration. RESULTS The MIC of RJ without starch was 1.7% (vol/vol) and 2% (vol/vol) against S. aureus and E. coli, respectively. When starch was incubated with RJ and then added to media, a significant MIC drop has been noticed against both strains. This MIC drop was 61% and 30% against S. aureus and E. coli, respectively. CONCLUSIONS The effectiveness of RJ against bacteria has been extensively reviewed, but this bee product remains unaffordable in most countries. Our findings suggest that combined mixture of RJ and starch could be used to treat infections that are resistant to conventional drugs, at a lower cost.