Antimicrobial Effects of Cinnamon and Rhubarb Extracts

The objectives of this study were to evaluate the antimicrobial efficacy of cinnamon essential oil (CEO) and rhubarb extract (REE) against 5 food-related microorganisms. The major active constituents of CEO were cinnamaldehyde (80.010%) and 2-methoxycinnamaldehyde (10.550%), and the major active constituents of REE were chrysophanic acid (54.950%) and physcion (13.270%). CEO and REE display strong inhibition against 5 strains. The checkerboard method was used to investigate the synergy antimicrobial potentiality of a combination of CEO and REE by analysis of the fractional inhibitory concentration index (FICI). The FICI was calculated and interpreted as synergy, addition, indifference, or antagonism. The combination showed additive efficacy against all tested microorganisms.