Synergistic Antibacterial, Antifungal and Antioxidant Efficacy of Cinnamon and Clove Essential Oils in Combination
The aim of the present investigation was to evaluate antibacterial, antifungal and antioxidant efficacy of essential oils of three commonly used spices (black pepper, cinnamon and clove) in combination along with chemical characterization of oil constituents and cytotoxic potential evaluation. Among the possible combinations tested, cinnamon /clove oil combination showed synergistic antibacterial activity against foodborne bacteria Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Escherichia coli and synergistic antifungal activity against Aspergillus niger in checkerboard titration method as well as in vitro synergistic antioxidant potential in DPPH model. GC-HRMS analysis revealed that out of thirteen identified components from clove oil, eugenol (53.9%)was the main constituent of the oil whereas out of eighteen identified constituents from cinnamon oil, the main constituent was cinnamaldehyde (59.04%).Cinnamon/clove oil combination did not show any cytotoxic potential at recommended dosage level in Allium cepa test (IC50> 1000µg/ml). The results provide evidence that cinnamon/clove oil combination might indeed be used as a potential source of safe and effective novel natural antibacterial, antifungal and antioxidant blend in the food and pharmaceutical industries. This research may provide a potential introduction to researchers in the field of study on synergism of essential oils to prevent both microbial proliferation caused by bacterial and fungal pathogens as well as oxidative deterioration in food at sufficiently low concentration.
Keywords - Essential oils, Foodborne microbes, Oxidation, Natural food preservatives, Synergistic interactions