Novel hydro-alcoholic sanitizer model with minimum alcohol content and fortified with eugenol and cinnamaldehyde as natural antimicrobial boosters

Abstract

Abstract Objectives 70% alcohol-based sanitizers are frequently used for decontamination and controlling infections caused by pathogenic microorganisms. In the current investigation the authors aimed at developing and evaluating novel diluted hydro-alcoholic sanitizer containing 70% water and less than 30% alcohol. That is due to the fact that excessive use of alcoholic sanitizers containing 70% alcohol leads to immergence of alcohol resistant strains of pathogenic bacteria. In addition, some other toxic and environmental issues arise from using such high amounts of alcohol in the common sanitizing formula. The developed formula in the current work was fortified with some natural anti-microbial boosters from aromatic plants like eugenol, cinnamaldehyde and their mixture to compensate for the low alcohol content. Methods The solubility of eugenol and cinnamaldehyde in 70% water-containing hydro-alcoholic solution was investigated using the Gibbs’ triangle phase diagram. The broth dilution assay was used to evaluate the growth inhibition of the developed formula against four pathogenic bacteria including L. monocytogenes, S. typhimurium, E. coli and P. aeruginosa. Results The phase diagram study indicated that 3% of each of the antimicrobial boosters (eugenol, cinnamaldehyde) can be incorporated homogenously into a diluted hydro-alcoholic sanitizer containing 70% water and only 27% alcohol. Antimicrobial evaluation of that formula at only half concentration of the antimicrobial boosters (1.5%) showed complete inhibition of the growth of the four tested pathogens, where the count after treatment was zero cfu/ml. This antimicrobial activity was similar to that of a standard alcoholic sanitizer that contains 70% alcohol. Conclusions The study represents an insight towards a new generation of sanitizers which are characterized by significantly minimum content of alcohol without compromising efficiency. That also represents a step toward lowering alcohol toxicity and reducing its vapors emission to the environment.