Synthesis and in vitro evaluation of peracetyl and deacetyl glycosides of eugenol, isoeugenol and dihydroeugenol acting against food-contaminating bacteria.

Essential oils, as well as their separate components, have shown promise as alternatives to synthetic preservatives. Therefore, it would be interesting to optimize the effect of these compounds and to evaluate their applicability as additives in food. To this end, six peracetyl and deacetyl glycosides were synthesized from eugenol, isoeugenol and dihydroeugenol. All of the glycosides were characterized by IR and NMR. The synthesized compounds and their aglycones were evaluated to determine their minimal bactericidal concentrations (MBC) against the spoilage food bacteria Escherichia coli, Listeria monocytogenes, Staphylococcus aureus and Salmonella enteritidis. All deacetyl glycosides were about twice as active as aglycones, and the peracetyl glycosides were, in most cases, equipotent with aglycones. The deacetyl glycoside of dihydroeugenol proved to be the most active compound against the bacteria tested, with a 0.37% MBC v/v for E. coli and 0.18% v/v for the other bacteria.