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Given the rise in the infectious diseases caused by pathogens, identification of medicinal plants and purification of their nutraceuticals can be useful in treating such diseases. In this experimental study, the antimicrobial activity of Dezfuli orange peel essential oil was examined on 3 Gram-negative strains (Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi) and 5 Gram-positive strains (Staphylococcus aureus, Bacillus cereus, Bacillus subtilis, Staphylococcus epidermidis and Listeria innocua) through agar disc diffusion, agar well diffusion, minimum inhibitory concentration (microdilution broth) and minimum bactericidal concentration. Furthermore, the interactions between the essential oil and chloramphenicol, gentamycin and tetracycline were investigated. The results of disc diffusion showed that the longest and shortest diameters of the growth inhibition zone belonged to B. cereus (21.20 mm) and L. innocua (13.20 mm) respectively. In the agar diffusion test, S. aureus and E. coli respectively had the longest (17.30 mm) and shortest (11.10 mm) diameters of the inhibition zone. The minimum inhibitory concentration was equal to 25, 400, 50, 12.5, 25, 25, 400 and 12.5 mg/ml for E. coli, P. aeruginosa, S. typhi, S. aureus, B. cereus, B. subtilis, S. epidermidis and L. innocua respectively. The minimum bactericidal concentration of the essential oil was greater than 400 mg/ ml for all the strains.

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Nowadays, due to the harmful effects of chemical preservatives in food products and antibiotic resistance too, the efforts of researchers to use natural and safe antimicrobial compounds, including plant essential oils, have increased. In the present study, after collecting the Badrashboo plant from the fields around Urmia city and drying it, extracting the essential oil from the plant was carried out using a Clevenger device, and the antimicrobial effects of this essential oil against some Gram-positive and Gram-negative food-borne pathogenic bacteria were determined by methods: Disk Diffusion Agar (DDA), Well Diffusion Agar (WDA), Minimum inhibitory concentration (MIC), Minimum bactericidal concentration (MBC) and interaction with four common broad-spectrum antibiotics including Vancomycin, Erythromycin, Chloramphenicol and Gentamicin were performed. The results of the DDA and WDA tests showed that the essential oil of Badreshbo had significant antimicrobial effects on all the tested bacteria in this study. The gram-positive bacteria were more sensitive than the gram-negative bacteria in front of this essential oil. The results of the MIC test of the essential oil for Salmonella typhimurium, Escherichia coli, Pseudomonas aeruginosa, Shigella dysentery, Staphylococcus aureus, Bacillus cereus, and Listeria monostogenes were 2.5, 1.25, 1.25, 0.625, 0.312, 1.25 and 1.25 mg/ml. The MBC of the mentioned strains were 5, 5, 2.5, 5, 2.5, 2.5, and 2.5 mg/mL, respectively. Also, the results of the study of the interaction effect of Badreshbo essential oil with the mentioned antibiotics indicate synergistic effects of the essential oil with all four antibiotics tested. Therefore, considering the significant antimicrobial effects observed for Badrashbo essential oil in this study, it can be used in the food and pharmaceutical industries.
 

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Although chemical antifungal preservatives are often used in various food products, the use of these substances has been limited due to their harmful effects on human health and the environment. Researchers have recently sought to replace these chemical compounds with natural and less dangerous substances. In this regard, using essential oils of medicinal plants can be considered a suitable alternative due to fewer side effects. Therefore, in the present research, after preparing the Badrashboo plant from the fields of Golmarz village located near Urmia city and drying it, extracting the essential oil from the Badrashboo was carried out using a Clevengerger, and the antifungal effect of Badrashboo essential oil on some important fungal strains with disc diffusion agar and well diffusion agar, minimum inhibitory concentration, minimum fungicidal concentration and the interaction of Badrashboo essential oil with Nystatin were performed. The results of disk diffusion agar and well diffusion agar tests showed that Badrashbo essential oil had a significant antifungal effect on all studied fungal strains. The results of the minimum inhibitory concentration of essential oil for strains of Saccharomyces cerevisiae, Candida albicans, Aspergillus niger, Fusarium solani, and Penicillium expansum were 8, 16, 2, 8, and 4 mg/ml, respectively. The minimum fungicidal concentration for the mentioned strains was 32, 64, 8, 16, and 32 mg/ml respectively. Also, the results of the interaction of Badrashboo essential oil with Nystatin indicated the synergistic effect of Badrashboo essential oil with Nystatin. Considering the significant antifungal effect observed for Badrashbo essential oil in the present study, it can be used in the food and pharmaceutical industries.