Antibacterial and Antioxidant Potential of Essential Oils of Five Spices

Background: Essential Oils (EOs) of spices may serve as a potential source of antibacterial and antioxidant agents due to the presence of a diverse group of phytochemicals. In the present investigation, an attempt has been made to seek EOs from five commonly used spices that have both strong antibacterial and antioxidant potential to shed some light on these important aspects. Methods: In vitro antibacterial efficacy of black cumin, black pepper, cinnamon, clove, and nutmeg EOs were evaluated against some food-borne bacteria using agar well diffusion, microbroth dilution, and time-kill assay methods. Antioxidant potential was evaluated by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, β-carotene linoleic acid bleaching and Fe2+ ion chelating methods. Chemical characterization of EO components was performed by Gas Chromatography-Mass Spectrometry (GC-MS). Statistical analysis of data was performed using SPSS software, version 18.0. Results: Black pepper, cinnamon, and clove EOs had significantly (p<0.05) higher antibacterial properties comparing to the black cumin oil and nutmeg EOs. Clove and cinnamon EOs showed the highest and lowest antioxidant potential, respectively. GC-MS analysis revealed that eugenol, cinnamaldehyde, and β-caryophyllene were the main constituents of clove, cinnamon, and black pepper oils, respectively. Conclusion: The results provide evidence that EOs of clove, black pepper, and cinnamon may serve as effective natural preservatives in the food industry. Further studies are needed for their plausible applications in the food industry.