Evaluation of antibacterial properties of essential oils and/or of their major components

La recherche de nouveaux traitements contre les maladies infectieuses est un sujet de pleine actualité : l’émergence et la dissémination des mécanismes de résistance aux antibactériens, l’importance croissante des infections associées aux soins, combinées à la quasi absence de nouveaux antibiotiques génèrent, au-delà de la santé individuelle, un véritable problème de santé publique. Il y a urgence à trouver et à proposer des nouvelles approches thérapeutiques pour le traitement de ces infections. Dans ce contexte, les Huiles Essentielles (HE) connues et utilisées depuis des siècles pour leurs propriétés anti-infectieuses, peuvent se révéler être une alternative au « tout antibiotique ». En effet, depuis plusieurs années, les HE connaissent un très net regain d’intérêt, et plusieurs études tendent à démontrer leurs réelles propriétés antimicrobiennes. Cependant, avant d’envisager toute utilisation des HE en thérapeutique anti-infectieuse, nous devons relever un défi de taille : à l’heure actuelle, aucun protocole expérimental, permettant d’évaluer in vitro les propriétés antibactériennes d’une HE, n’est validé ou recommandé par aucune autorité règlementaire, quelle qu’elle soit (Pharmacopée, ISO, ANSM…). L’objectif de cette revue est de présenter les différentes techniques utilisées ou utilisables pour l’évaluation in vitro des propriétés antibactériennes d’une HE, en soulignant les avantages et les inconvénients de chacune.The search for new treatments against infectious diseases is currently highlighted : the emergence and dissemination of resistance mechanisms to antibacterial drugs, the increasing importance of infections associated to healthcare, combined with the quasi inexistence of new antibiotics generates, beyond individual health, a real problem of public health. It is now urgent to find and to propose new therapeutic approaches for the treatment of these infections. In this context, essential oils (EO) known and used for centuries for their anti-infectious properties, may present as an alternative to “all-antibiotic”. As a matter of fact, since many years now E O aroused considerable new interest and many studies tend to support their real antimicrobial properties. However, before envisaging the use of EO in infectious therapeutics, we must face a considerable challenge: currently no experimental protocol allowing and in vitro evaluation of the antibacterial properties of an EO has been validated or recommended by any health authority whatsoever. The aim of this review is to present the different techniques used or which could be used for the in vitro evaluation of antibacterial properties of EO, underlining the advantages and drawbacks of each

Coopérer pour se découvrir et développer ses compétences sociales

Les compétences sociales se travaillent tout au long de la vie et doivent s’apprendre au plus tôt car elles sont indispensables dans la vie professionnelle. La coopération notamment est une compétence essentielle dans une entreprise et c’est pour cela qu’elle est utilisée comme moyen pédagogique dans la formation proposée par les deux programmes Initiatives d’Excellences en Formations Innovantes (IDEFI). Ceux-ci se sont associés pour proposer aux étudiants en L2 Sciences pour la Santé de l’Université de Lorraine de « booster leur réussite » par le développement des compétences sociales. Grâce à une semaine de formation basée sur la coopération, les étudiants ont pu travailler leurs compétences sociales et augmenter leur confiance en eux

Collaborer pour se découvrir et développer ses compétences sociales

International audienceLe travail en équipe est une compétence qui doit s’apprendre lorsqu’on est étudiant car elle est indispensable dans la vie professionnelle. Pour cela, deux programmes Initiatives d’Excellences en Formations Innovantes (IDEFI) se sont associés pour proposer aux étudiants en L2 Sciences pour la Santé de l’Université de Lorraine de « booster leur réussite » par le développement des compétences sociales. Grâce à une semaine de formation basée sur la coopération et le travail en équipe, les étudiants ont pu augmenter leur confiance en eux

On the Plants Leaves Boundary, "Jupe \`a Godets" and Conformal Embeddings

The stable profile of the boundary of a plant's leaf fluctuating in the direction transversal to the leaf's surface is described in the framework of a model called a "surface \`a godets". It is shown that the information on the profile is encoded in the Jacobian of a conformal mapping (the coefficient of deformation) corresponding to an isometric embedding of a uniform Cayley tree into the 3D Euclidean space. The geometric characteristics of the leaf's boundary (like the perimeter and the height) are calculated. In addition a symbolic language allowing to investigate statistical properties of a "surface \`a godets" with annealed random defects of curvature of density $q$ is developed. It is found that at $q=1$ the surface exhibits a phase transition with critical exponent $\alpha=1/2$ from the exponentially growing to the flat structure.Comment: 17 pages (revtex), 8 eps-figures, to appear in Journal of Physics

Deprotometalation-iodolysis and computed CH acidity of 1,2,3- and 1,2,4-triazoles. Application to the synthesis of resveratrol analogues

International audience1-Aryl- and 2-aryl-1,2,3-triazoles were synthesized by N-arylation of the corresponding azoles using aryl iodides. The deprotometalations of 1-phenyl-1,2,3-triazole and -1,2,4-triazole were performed using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination and occurred at the most acidic site, affording by iodolysis the 5-substituted derivatives. Dideprotonation was noted from 1-(2-thienyl)-1,2,4-triazole by increasing the amount of base. From 2-phenyl-1,2,3-triazoles, and in particular from 2-(4-trifluoromethoxy)phenyl-1,2,3-triazole, reactions at the 4 position of the triazolyl, but also ortho to the triazolyl on the phenyl group, were observed. The results were analyzed with the help of the CH acidities of the substrates, determined in THF solution using the DFT B3LYP method. 4-Iodo-2-phenyl-1,2,3-triazole and 4-iodo-2-(2-iodophenyl)-1,2,3-triazole were next involved in Suzuki coupling reactions to furnish the corresponding 4-arylated and 4,2’-diarylated derivatives. When evaluated for biological activities, the latter (which are resveratrol analogues) showed moderate antibacterial activity and promising antiproliferative effect against MDA-MB-231 cell line

Laser spectroscopy for breath analysis : towards clinical implementation

Detection and analysis of volatile compounds in exhaled breath represents an attractive tool for monitoring the metabolic status of a patient and disease diagnosis, since it is non-invasive and fast. Numerous studies have already demonstrated the benefit of breath analysis in clinical settings/applications and encouraged multidisciplinary research to reveal new insights regarding the origins, pathways, and pathophysiological roles of breath components. Many breath analysis methods are currently available to help explore these directions, ranging from mass spectrometry to laser-based spectroscopy and sensor arrays. This review presents an update of the current status of optical methods, using near and mid-infrared sources, for clinical breath gas analysis over the last decade and describes recent technological developments and their applications. The review includes: tunable diode laser absorption spectroscopy, cavity ring-down spectroscopy, integrated cavity output spectroscopy, cavity-enhanced absorption spectroscopy, photoacoustic spectroscopy, quartz-enhanced photoacoustic spectroscopy, and optical frequency comb spectroscopy. A SWOT analysis (strengths, weaknesses, opportunities, and threats) is presented that describes the laser-based techniques within the clinical framework of breath research and their appealing features for clinical use.Peer reviewe

Limitations of Recent Studies Dealing with the Antibacterial Properties of Silver Nanoparticles: Fact and Opinion

Due to the constant increase in the number of infectious diseases and the concomitant lack of treatment available, metallic nanoparticles (e.g., silver nanoparticles) have been of particular interest in the last decades. Indeed, several studies suggest that silver nanoparticles have valuable antimicrobial activities, especially against bacteria, which may lead us to think that these nanoparticles may one day be an attractive therapeutic option for the treatment of bacterial infections. Unfortunately, when we look a little closer to these studies, we can see a very great heterogeneity (e.g., in the study design, in the synthetic process of nanoparticles, in the methods that explore the antibacterial properties of nanoparticles and in the bacteria chosen) making cross-interpretation between these studies impossible, and significantly limiting the interest of silver nanoparticles as promising antibacterial agents. We have selected forty-nine international publications published since 2015, and propose to discuss, not the results obtained, but precisely the different methodologies developed in these publications. Through this discussion, we highlighted the aspects to improve, or at least to homogenize, in order to definitively establish the interest of silver nanoparticles as valuable antibacterial agents

Généralités sur les antibiotiques par voie systémique et principes d'utilisation

International audienc

Human Coronaviruses: Insights into Environmental Resistance and Its Influence on the Development of New Antiseptic Strategies

viruse

Antimicrobial Spectrum of Titroleane™: A New Potent Anti-Infective Agent

Tea Tree oil (TTO) is well known for its numerous good properties but might be also irritating or toxic when used topically or ingested, thus limiting the number of possible applications in Humans. The aim of the study was to characterize the antimicrobial spectrum as well as the toxicity of Titroleane™, a new anti-infective agent obtained from TTO but cleared of its toxic monoterpenes part. The susceptibility to Titroleane™ of various pathogens (bacteria and fungi) encountered in animal and human health was studied in comparison with that of TTO. Antimicrobial screening was carried out using the broth microdilution method. Activities against aerobic, anaerobic, fastidious and non-fastidious microorganisms were performed. For all microorganisms tested, the MIC values for Titroleane™ ranged from 0.08% to 2.5%, except for Campylobacter jejuni, and Aspergillus niger. In particular, Titroleane™ showed good efficacy against skin and soft tissue infection pathogens, such as methicillin resistant Staphylococcus aureus (MRSA), intra-abdominal infections and oral pathogens, as well as fish farming pathogens. Toxicity testing showed little and similar cytotoxicities between TTO and Titroleane™ of 37% and 23%, respectively at a concentration of 0.025% (v/v). Finally, we demonstrated that the antimicrobial activity of Titroleane™ is similar to that of TTO