Inhibitory effects of cinnamon and thyme essential oils against
            Salmonella
            spp. in hummus (chickpea dip)

Plant bioactive compounds have antimicrobial and antioxidant activities that allow them to be used as a substitute for synthetic chemical additives in both food and food packaging. To improve its sensory and bactericidal effects, its use in the form of effective combinations has emerged as an interesting possibility in the food industry. In this study, the antimicrobial activities of essential oils (EOs) of cinnamon bark, cinnamon leaves, and clove and the pure compounds vanillin, eugenol, and cinnamaldehyde were investigated individually and in combination against Listeria monocytogenes and Escherichia coli O157:H7. The possible interactions of combinations of pure compounds and EOs were performed by the two-dimensional checkerboard assay and isobologram methods. Vanillin exhibited the lowest antimicrobial activity (MIC of 3002 ppm against L. monocytogenes and 2795 ppm against E. coli O157:H7), while clove and cinnamon bark EOs exhibited the highest antimicrobial activity (402–404 against L. monocytogenes and 778–721 against E. coli O157:H7). For L. monocytogenes, pure compound eugenol, the main component of cinnamon leaves and clove, showed lower antimicrobial activity than EOs, which was attributed to the influence of the minor components of the EOs. The same was observed with cinnamaldehyde, the main component of cinnamon bark EO. The combinations of vanillin/clove EO and vanillin/cinnamon bark EO showed the most synergistic antimicrobial effect. The combination of the EOs of cinnamon bark/clove and cinnamon bark/cinnamon leaves showed additive effect against L. monocytogenes but indifferent effect against E. coli O157:H7. For L. monocytogenes, the best inhibitory effects were achieved by cinnamon bark EO (85 ppm)/vanillin (910 ppm) and clove EO (121 ppm)/vanillin (691 ppm) combinations. For E. coli, the inhibitory effects of clove EO (104 ppm)/vanillin (1006 ppm) and cinnamon leaves EO (118 ppm)/vanillin (979 ppm) combinations were noteworthy. Some of the tested combinations increased the antimicrobial effect and would allow the effective doses to be reduced, thereby offering possible new applications for food and active food packaging.

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Empirical prediction and validation of antibacterial inhibitory effects of various plant essential oils on common pathogenic bacteria

International Journal of Food Microbiology ◽

10.1016/j.ijfoodmicro.2015.02.030 ◽

2015 ◽

Vol 202 ◽

pp. 35-41 ◽

Cited By ~ 38

Author(s):

Gulsun Akdemir Evrendilek

Keyword(s):

Essential Oils ◽

Pathogenic Bacteria ◽

Inhibitory Effects ◽

Empirical Prediction ◽

Plant Essential Oils

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Effects of Essential Oils on Escherichia coli Inactivation in Cheese as Described by Meta-Regression Modelling

Foods ◽

10.3390/foods9060716 ◽

2020 ◽

Vol 9 (6) ◽

pp. 716

Author(s):

Beatriz Nunes Silva ◽

Vasco Cadavez ◽

José António Teixeira ◽

Ursula Gonzales-Barron

Keyword(s):

Escherichia Coli ◽

Essential Oils ◽

Meta Analysis ◽

Inhibitory Effects ◽

Food Preservatives ◽

E Coli ◽

Log Reduction ◽

Bactericidal Properties ◽

Study Characteristics ◽

Meta Regression

The growing intention to replace chemical food preservatives with plant-based antimicrobials that pose lower risks to human health has produced numerous studies describing the bactericidal properties of biopreservatives such as essential oils (EOs) in a variety of products, including cheese. This study aimed to perform a meta-analysis of literature data that could summarize the inactivation of Escherichia coli in cheese achieved by added EOs; and compare its inhibitory effectiveness by application method, antimicrobial concentration, and specific antimicrobials. After a systematic review, 362 observations on log reduction data and study characteristics were extracted from 16 studies. The meta-regression model suggested that pathogenic E. coli is more resistant to EO action than the non-pathogenic type (p < 0.0001), although in both cases the higher the EO dose, the greater the mean log reduction achieved (p < 0.0001). It also showed that, among the factual application methods, EOs’ incorporation in films render a steadier inactivation (p < 0.0001) than when directly applied to milk or smeared on cheese surface. Lemon balm, sage, shallot, and anise EOs showed the best inhibitory outcomes against the pathogen. The model also revealed the inadequacy of inoculating antimicrobials in cheese purposely grated for performing challenge studies, as this non-realistic application overestimates (p < 0.0001) the inhibitory effects of EOs.

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Composition and Antibacterial Activity of Essential Oils from Leaf, Stem and Root of Chrysanthemum parthenium (L.) Bernh. from Iran

Natural Product Communications ◽

10.1177/1934578x0900400624 ◽

2009 ◽

Vol 4 (6) ◽

pp. 1934578X0900400 ◽

Cited By ~ 4

Author(s):

Ali Shafaghat ◽

Hajar Sadeghi ◽

Khodamali Oji

Keyword(s):

Escherichia Coli ◽

Staphylococcus Aureus ◽

Antibacterial Activity ◽

Essential Oils ◽

Salmonella Typhi ◽

Inhibitory Effects ◽

Germacrene D ◽

Leaf Oil ◽

Main Components ◽

Microdilution Broth

The water distilled essential oils from leaves, stems and roots of Chrysanthemum parthenium (L.) Bernh. were analyzed by GC and GC/MS methods. The leaf oil was characterized by a high amount of camphor (56.4%), whereas in the stem oil, camphor (26.0%), trans-β-ocimene (23.6%) and germacrene-d (15.0%) were the major constituents. The main components of the root oil were α-pinene (50.0%), trans-β-farnesene (13.8%) and bicyclogermacrene (11.0%). Antibacterial activity of the leaf, stem and root oil were evaluated using the microdilution broth method. The oils showed inhibitory effects on Escherichia coli and Salmonella typhi, but were not active against Staphylococcus aureus.

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Geranium and Lemon Essential Oils and Their Active Compounds Downregulate Angiotensin-Converting Enzyme 2 (ACE2), a SARS-CoV-2 Spike Receptor-Binding Domain, in Epithelial Cells

Plants ◽

10.3390/plants9060770 ◽

2020 ◽

Vol 9 (6) ◽

pp. 770 ◽

Cited By ~ 4

Author(s):

K. J. Senthil Kumar ◽

M. Gokila Vani ◽

Chung-Shuan Wang ◽

Chia-Chi Chen ◽

Yu-Chien Chen ◽

...

Keyword(s):

Epithelial Cells ◽

Angiotensin Converting Enzyme ◽

Essential Oils ◽

Cell Receptor ◽

Gas Chromatography Mass Spectrometry ◽

Converting Enzyme ◽

Inhibitory Effects ◽

Angiotensin Converting Enzyme 2 ◽

Host Cell Receptor ◽

Lemon Oil

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), also known as coronavirus disease-2019 (COVID-19), is a pandemic disease that has been declared as modern history’s gravest health emergency worldwide. Until now, no precise treatment modality has been developed. The angiotensin-converting enzyme 2 (ACE2) receptor, a host cell receptor, has been found to play a crucial role in virus cell entry; therefore, ACE2 blockers can be a potential target for anti-viral intervention. In this study, we evaluated the ACE2 inhibitory effects of 10 essential oils. Among them, geranium and lemon oils displayed significant ACE2 inhibitory effects in epithelial cells. In addition, immunoblotting and qPCR analysis also confirmed that geranium and lemon oils possess potent ACE2 inhibitory effects. Furthermore, the gas chromatography-mass spectrometry (GC–MS) analysis displayed 22 compounds in geranium oil and 9 compounds in lemon oil. Citronellol, geraniol, and neryl acetate were the major compounds of geranium oil and limonene that represented major compound of lemon oil. Next, we found that treatment with citronellol and limonene significantly downregulated ACE2 expression in epithelial cells. The results suggest that geranium and lemon essential oils and their derivative compounds are valuable natural anti-viral agents that may contribute to the prevention of the invasion of SARS-CoV-2/COVID-19 into the human body.

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Inhibitory Effects of Spice Essential Oils on the Growth of Bacillus Species

Journal of Medicinal Food ◽

10.1089/jmf.2006.9.418 ◽

2006 ◽

Vol 9 (3) ◽

pp. 418-421 ◽

Cited By ~ 18

Author(s):

Mehmet Musa Özcan ◽

Osman Saǧdıç ◽

Gülcan Özkan

Keyword(s):

Essential Oils ◽

Bacillus Species ◽

Inhibitory Effects

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Antimicrobial effects of spices and herbs essential oils

Acta periodica technologica ◽

10.2298/apt0940195s ◽

2009 ◽

pp. 195-209 ◽

Cited By ~ 16

Author(s):

Marija Skrinjar ◽

Nevena Nemet

Keyword(s):

Antimicrobial Activity ◽

Essential Oils ◽

Food Additives ◽

Inhibitory Effect ◽

Natural Food ◽

Garlic Mustard ◽

Salmonella Spp ◽

Food Preservatives ◽

Bacteria And Fungi ◽

Staphylococcus Spp

Spices and herbs have been used as food additives since ancient times, as flavouring agents but also as natural food preservatives. A number of spices shows antimicrobial activity against different types of microorganisms. This article gives a literature review of recent investigations considering antimicrobial activity of essential oils widely used spices and herbs, such as garlic, mustard, cinnamon, cumin, clove, bay, thyme, basil, oregano, pepper, ginger, sage, rosemary etc., against most common bacteria and fungi that contaminate food (Listeria spp., Staphylococcus spp., Salmonella spp., Escherichia spp., Pseudomonas spp., Aspergillus spp., Cladosporium spp. and many others). Antimicrobial activity depends on the type of spice or herb, type of food and microorganism, as well as on the chemical composition and content of extracts and essential oils. Summarizing results of different investigations, relative antimicrobial effectiveness can be made, and it shows that cinnamon, cloves and mustrad have very strong antimicrobial potential, cumin, oregano, sage, thyme and rosemary show medium inhibitory effect, and spices such as pepper and ginger have weak inhibitory effect.

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