Antimicrobial mechanism of the major active essential oil compounds and their structure–activity relationship

Xian, Hui; Yan, Gao; Tian, Fang-Lin; Li, Heng; Gao, Wenhua

doi:10.1007/s00044-016-1762-0

Cited by 29 publications

(26 citation statements)

References 44 publications

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“…Different extracted components from EOs such as carvacrol, thymol, eugenol, perillaldehyde, and cinnamaldehyde have been reported as antibacterial agents [ 17 ]. However, the reported values for their minimum inhibitory (MICs) and bactericidal (MBCs) concentrations are extremely divergent.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Antimicrobial Activity and Cytotoxicity of Different Components of Natural Origin Present in Essential Oils

et al. 2018

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Even though essential oils (EOs) have been used for therapeutic purposes, there is now a renewed interest in the antimicrobial properties of phytochemicals and EOs in particular. Their demonstrated low levels of induction of antimicrobial resistance make them interesting for bactericidal applications, though their complex composition makes it necessary to focus on the study of their main components to identify the most effective ones. Herein, the evaluation of the antimicrobial action of different molecules present in EOs against planktonic and biofilm-forming Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria was assessed. The bactericidal mechanisms of the different molecules, as well as their cytocompatibility, were also studied. Carvacrol, cinnamaldehyde, and thymol exhibit the highest in vitro antimicrobial activities against E. coli and S. aureus, with membrane disruption the bactericidal mechanism identified. The addition of those compounds (≥0.5 mg/mL) hampers S. aureus biofilm formation and partially eliminates preformed biofilms. The subcytotoxic values of the tested EO molecules (0.015–0.090 mg/mL) are lower than the minimum inhibitory and bactericidal concentrations obtained for bacteria (0.2–0.5 mg/mL) but are higher than that obtained for chlorhexidine (0.004 mg/mL), indicating the reduced cytotoxicity of EOs. Therefore, carvacrol, cinnamaldehyde, and thymol are molecules contained in EOs that could be used against E. coli– and S. aureus–mediated infections without a potential induction of bactericidal resistance and with lower cell toxicity than the conventional widely used chlorhexidine.

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Section: Introductionmentioning

confidence: 99%

Evaluation of the Antimicrobial Activity and Cytotoxicity of Different Components of Natural Origin Present in Essential Oils

et al. 2018

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“…The discovery of new drugs has been based on natural products for years, either by the synthesis of substances that mimic a natural product, by modifying an existing natural molecule, or by the use of the natural product itself [ 12 ]. Among natural products, monoterpenes stand out for their wide use in the industry, in addition to having vast biological activity already verified against fungi, bacteria, viruses, and parasites, including protozoa [ 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Thus, the present work aims to investigate the relationship between chemical structures and the activity of different monoterpenes and a phenylpropanoide, constituents of essential oils, against promastigote forms of Leishmania amazonensis .…”

Section: Introductionmentioning

confidence: 99%

Leishmanicidal Activity and Structure-Activity Relationships of Essential Oil Constituents

et al. 2017

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Several constituents of essential oils have been shown to be active against pathogens such as bacteria, fungi, and protozoa. This study demonstrated the in vitro action of ten compounds present in essential oils against Leishmania amazonensis promastigotes. With the exception of p-cymene, all evaluated compounds presented leishmanicidal activity, exhibiting IC50 between 25.4 and 568.1 μg mL−1. Compounds with the best leishmanicidal activity presented a phenolic moiety (IC50 between 25.4 and 82.9 μg mL−1). Alicyclic alcohols ((−)-menthol and isoborneol) and ketones ((−)-carvone) promoted similar activity against the parasite (IC50 between 190.2 and 198.9 μg mL−1). Most of the compounds showed low cytotoxicity in L929 fibroblasts. Analysis of the structure-activity relationship of these compounds showed the importance of the phenolic structure for the biological action against the promastigote forms of the parasite.

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Section: Biophysical Properties Of Bacteria Treated By Free and Nanoementioning

confidence: 99%

“…The latter was studied for the inhibition of 1-deoxy-D-xylulose 5-phosphate reductoisomerase (DXR) [30], a key enzyme of the methylerythritol phosphate pathway [29]. Eugenol had a much higher activity than carvacrol, thymol, and linalool inhibiting DXR and the mode of inhibition was observed to be competitive, indicating the specificity of binding between eugenol and DXR [29,30]. These mechanisms may be used to understand impact of nanoencapsulation on eugenol-bacterium interactions based on the measured biophysical properties, although variations in eugenol concentration, bacterial population, and treatment temperature and duration adopted for different assays may not allow direct correlation of all sets of data.…”

Section: Biophysical Properties Of Bacteria Treated By Free and Nanoementioning

confidence: 99%

Eugenol Nanoencapsulated by Sodium Caseinate: Physical, Antimicrobial, and Biophysical Properties

Zhang

Kang²,

Zhong³

2017

Food Biophysics

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To improve the application of essential oils as natural antimicrobial preservatives, the objective of the present study was to determine physical, antimicrobial, and biophysical properties of eugenol after nanoencapsulation by sodium caseinate (NaCas). Emulsions were prepared by mixing eugenol in 20.0 mg/mL NaCas solution at an overall eugenol content of 5.0-137.9 mg/mL using shear homogenization. Stable emulsions were observed up to 38.5 mg/mL eugenol, which had droplet diameters of smaller than 125 nm at pH 5-9 after ambient storage for up to 30 days. The encapsulated eugenol had similar minimal inhibitory and minimal bactericidal concentrations as free eugenol against Escherichia coli O157:H7 ATCC 43895, Listeria monocytogenes Scott A, and Salmonella Enteritidis but showed better inhibition of E. coli O157:H7 than free eugenol during incubation at 37 °C for 48 h. After 20 min interaction at 21 °C, bacteria treated with encapsulated eugenol had a greater reduction of intracellular ATP and a greater increase of extracellular ATP than free eugenol, suggesting the enhanced permeation of eugenol after nanoencapsulation. However, such overall trend was not observed when examining bacterial morphology and uptake of crystal violet, suggesting the possible membrane adaptation. Findings from this study showed the feasibility of preparing nanoemulsions with high loading of eugenol using NaCas.

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Antimicrobial mechanism of the major active essential oil compounds and their structure–activity relationship

Cited by 29 publications

References 44 publications

Evaluation of the Antimicrobial Activity and Cytotoxicity of Different Components of Natural Origin Present in Essential Oils

Evaluation of the Antimicrobial Activity and Cytotoxicity of Different Components of Natural Origin Present in Essential Oils

Leishmanicidal Activity and Structure-Activity Relationships of Essential Oil Constituents

Eugenol Nanoencapsulated by Sodium Caseinate: Physical, Antimicrobial, and Biophysical Properties

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