Chemical composition of essential oils of some common culinary spices and their antimicrobial activities

Antimicrobial resistance is one of the top 10 global threats to public health. Natural products can be effectively used to prevent antimicrobial resistance. Spices are highly used food commodities. Their essential oils (EOs) possess excellent antimicrobial potential. Therefore, the present study aimed to extract oil from three commonly used spices and assess their antimicrobial activity.The EOs were extracted from cinnamon (Cinnamomum verum J. Persel), cumin (Cuminum cyminum L.) and trigonella (Trigonella foenum-graecum L.) and were characterized by GC-MS. Antimicrobial activities were screened against two Gram +ve bacterial strains: Staphylococcus aureus (MTCC No. 737), Bacillus subtilis (MTCC No. 441); two Gram-ve bacterial strains, Escherichia coli (MTCC No. 443), Pseudomonas aeruginosa (MTCC No. 1688); and two fungal strains: Aspergillus oryzae(NCIM1008) and Fusarium oxysporum (MDU-4) via disc diffusion and broth dilution assays.The highest yield of EOs was obtained with trigonella (4.35 %), followed by cinnamon (2.75%) and cumin (1.53%). GC-MS analysis confirmed the presence of various phytocompounds in different EOs. Antimicrobial results showed that cinnamon EO was the most active with the maximum zone of inhibition of 15.3±0.08 mm, 11.3±0.25 mm, and 13.1±0.14 mm against E. coli, P. aeruginosa, and F. oxysporum, respectively. Cumin EOhas also shown promising antimicrobial activity with a zone of inhibition of 13.0±0.09 mm, 10.2±0.20 mm, and 11.4±0.08 mm against E. coli, P. aeruginosa, and F. oxysporum. E. coli and F. oxysporum were the most sensitive microbial strains.Cinnamon EO exhibited the highest antimicrobial activity and, therefore, can be used as a natural antimicrobial herb after clinical trials.