Essential Oils from Indigenous Iranian Plants: A Natural Weapon vs. Multidrug-Resistant Escherichia coli

Abstract: Aim of this study was to investigate the antimicrobial properties of herbal plant essential oils (EOs) from selected Iranian plant species such as Ferulago angulata, Zataria multiflora, Cuminum cyminum, and Mentha longifolia against antibiotic-resistant Escherichia coli (E. coli) strains. For this purpose, the Escherichia coli strains, isolated from raw cow’s milk and local dairy products (yogurt, cream, whey, cheese, and confectionery products) collected from different areas of Hamedan province, Iran, were investigated for their resistance to antibiotics (i.e., streptomycin, tetracycline, gentamicin, chloramphenicol, ciprofloxacin, and cefixime). Thus, the E. coli strains were tested for their susceptibility to the above-mentioned essential oils. Regarding antibiotics, the E. coli strains were highly sensitive to ciprofloxacin. In relation to essential oils, the most effective antibacterial activity was observed with Zataria multiflora; also, the bacteria were semi-sensitive to Cuminum cyminum and Mentha longifolia essential oils. All strains were resistant to Ferulago angulata essential oil. According to the results, the essential oil of Zataria multiflora can be considered as a practical and alternative antibacterial strategy to inhibit the growth of multidrug-resistant E. coli of dairy origin. Keywords: antibiotic susceptibility; pathogen; Zataria multiflora; essential oils; dairy product

Evaluating of Heavy Metal Contaminations in the Most Applicable Food Spices and Flavors in Hamedan, Iran

Background & Aims of the Study: Iranian food diet contains nutrients and herbal spices. From the most important challenges in relation to these spices is their pollution with various heavy metals. Thus, this study aims to characterize the amounts of heavy metals in collected spices from Hamedan city of Iran during 2015-2016. Materials & Methods: 180 samples of commercially accessible vegetal spices were collected from local stores all over the Hamedan city. The samples were weighted and dried in an electrical oven at 105 ±1 °C for 24 h. Then, samples were grounded to powder by a grinder. Afterwards, the samples were digested by adding 4 ml and 1 ml of concentrated nitric acid and hydrogen peroxide, respectively. After filtration of samples, flamed atomic absorption used for detection of Zinc, Copper, Iron, Nickel, Manganese, Cadmium and Lead concentrations. For the statistical analysis of the results, SPSS version 21 was used. For examining data normality, Kolmogorov-Smirnov test; to compare the mean concentration of elements between spice samples from Tukey test and in order to investigate the correlation between the average concentrations of the heavy metals in the samples, Pearson correlation test were used. Comparing mean concentration of elements with standard values was conducted, using one-sample t-test.                                                                                                                           Results: The mean concentrations of Cadmium as a toxic trace element were low in all samples and no risk threatens consumers. But, lead content in dried mint (6.04±0.85mg/kg) was high compared to the standard values. This trend was followed by cinnamon (4.88±1.32), turmeric (2.05±0.63), black pepper (1.51±0.63), sumac (1.17±1.08) and red pepper (0.72±0.85). Conclusion: Lead in dried mint exceeded the standard value whose reason can be the increase of population, mining, industrialization, transportation and usage of chemical fertilizers, leading to the spread of environmental pollution. Thus, more serious health cares and regular periodic supervisions on food spices regarding pollution with this element seem necessary

Influence of extraction techniques on the efficiency of pomegranate (Punica granatum L.) peel extracts in oxidative stability of edible oils

In this study, the effects of pomegranate (Punica granatum L.) peel extract (PPE) on the oxidative stability of soybean oil and ghee were investigated under heat conditions. Three extraction methods (immersion, ultrasound, and combined immersion-ultrasound) with eight solvents (hot water, cold water, absolute methanol, methanol 50%, absolute ethanol, ethanol 50%, absolute acetone, and acetone 50%) were used for the evaluation of the extracts. Ethanolic extract in maceration method significantly (p ≤ .05) showed the highest DPPH radical scavenging activity (95.018%), reducing power (3.981), and total phenolic content (520 mg GAE/g) compared to the other samples. Then, the effects of PPE in various concentrations (200, 400, 600, and 800 ppm) were compared to the synthetic antioxidant (Butylated hydroxytoluene 200 ppm) in the oxidative stability of soybean oil under 65°C and ghee under 55°C for 24 days with 6-day intervals, respectively. During storage period, all treatments showed a significant decrease (p ≤ .05) in peroxide value, thiobarbituric acid reactive substances, conjugated dienes value, polar compounds value, and acid value compared to the control. Except for the PPE 200 treatment, the other treatments exhibited superior efficiency to the synthetic antioxidant in a dose-dependent manner in accelerated stored edible oils. Based on the sensory analyses (flavor, odor, color, and overall acceptability), PPE significantly (p ≤ .05) preserved the sensory features compared to the control group during the entire storage time. PPE 800 ppm was the most efficient treatment in all analyses, followed by PPE 600, 400, and 200 ppm, respectively. Finally, it was concluded that PPE can be introduced as a unique alternative to synthetic antioxidants in edible oils under heating conditions

A cytotoxicity and comparative antibacterial study on the effect of Zataria multiflora Boiss, Trachyspermum copticum essential oils, and Enrofloxacin on Aeromonas hydrophila

Objective: this study designed to test the antibacterial potency of enrofloxacin (ENR) and essential oils from Zataria multiflora Boiss (ZEO) and Trachyspermum copticum (TEO) on Aeromonas hydrophila. Material and Methods: The antibacterial potency of test compounds was determined by several methods including the inhibition zone diameter determination, microbroth dilution method and colorimetric method of MTT. The cytotoxicity of test substances was assessed on Chinook salmon (Oncorhynchus tshawytscha) embryo (CHSE-214) cells. Results: Results showed that ENR and tested essential oils exert antibacterial effect against A. hydrophila. Moreover, ENR exerted the most potent antibacterial effect with MIC values of 62.5 ng/ml. The natural compounds of ZEO and TEO also showed antibacterial effects with rather high MIC values of 0.315 mg/ml, and 1.25 mg/ml, respectively. None of the tested substances showed toxicity on CHSE-24 cells. Conclusion: It is concluded that ZEO and TEO could be applied to prevent from A. hydrophila infection. Moreover, data also suggest that MTT method could be both cost- and time-effective and accurate method of MIC determination

A cytotoxicity and comparative antibacterial study on the effect of Zataria multiflora Boiss, Trachyspermum copticum essential oils, and Enrofloxacin on Aeromonas hydrophila

Objective: this study designed to test the antibacterial potency of enrofloxacin (ENR) and essential oils from Zataria multiflora Boiss (ZEO) and Trachyspermum copticum (TEO)on Aeromonas hydrophila. Material and Methods: The antibacterial potency of test compounds was determined by several methods including the inhibition zone diameter determination, microbroth dilution method and colorimetric method of MTT. The cytotoxicity of test substances was assessed on Chinook salmon (Oncorhynchus tshawytscha) embryo (CHSE-214) cells. Results: Results showed that ENR and tested essential oils exert antibacterial effect against A. hydrophila. Moreover, ENR exerted the most potent antibacterial effect with MIC values of 62.5 ng/ml. The natural compounds of ZEO and TEO also showed antibacterial effects with rather high MIC values of 0.315 mg/ml, and 1.25 mg/ml, respectively. None of the tested substances showed toxicity on CHSE-24 cells. Conclusion: It is concluded that ZEO and TEO could be applied to prevent from A. hydrophila infection. Moreover, data also suggest that MTT method could be both cost- and time-effective and accurate method of MIC determination