In vitro Antimicrobial Activity and Effect on E. Coli Integrity of Cinnamon Essential Oil and Rhubarb Ethanol Extract

The objectives of this study were to evaluate the antimicrobial efficacy of cinnamon essential oil (CEO) and rhubarb ethanol extract (REE) against 5 food-related microorganisms and to investigate effect on E. coli integrity. The main chemical components (>0.1%) of CEO and REE were analyzed by GC/MS. The major active constituents of CEO were cinnamaldehyde and 2-methoxycinnamaldehyde, and the major active constituents of REE were chrysophanic acid and physcion. The antimicrobial efficacy of combination of CEO and REE was investigated by analysis of the fractional inhibitory concentration index. The combination showed additive efficacy against all tested microorganisms. Furthermore, the scanning electron microscope observations and the K+ concentration change in broth confirmed the physical damage and considerable morphological alteration to the E. coli treated with CEO, REE and combination of them. Thus, our study demonstrated that CEO and REE can be considered potential alternatives to control pathogens and microbial spoilage issues.