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The emergence and spread of drug-resistant pathogens, resulting in antimicrobial resistance, continue to compromise our capability to handle commonly occurring infectious diseases. The rapid global spread of multi-drug-resistant pathogens, particularly systemic fungal infections, presents a significant concern, as existing antimicrobial drugs are becoming ineffective against them. In recent decades, there has been a notable increase in systemic fungal infections, primarily caused by Candida species, which are progressively developing resistance to azoles. Moreover, Candida species biofilms are among the most common in clinical settings. In particular, they adhere to biomedical devices, growing as a resilient biofilm capable of withstanding extraordinarily high antifungal concentrations. In recent years, many research programs have concentrated on the development of novel compounds with possible antimicrobial effects to address this issue, and new sources, such as plant-derived antimicrobial compounds, have been thoroughly investigated. Essential oils (EOs), among their numerous pharmacological properties, exhibit antifungal, antibacterial, and antiviral activities and have been examined at a global scale as the possible origin of novel antimicrobial compounds. A recent work carried out by our research group concerned the synergistic antibacterial activities of commercially available and chemically characterized Cinnamomum verum L. essential oil (C. verum EO) in association with sertraline, a selective serotonin reuptake inhibitor whose repositioning as a non-antibiotic drug has been explored over the years with encouraging results. The aim of this work was to explore the synergistic effects of C. verum EO with sertraline on both planktonic and sessile Candida species cells. Susceptibility testing and testing of the synergism of sertraline and C. verum EO against planktonic and sessile cells were performed using a broth microdilution assay and checkerboard methods. A synergistic effect was evident in both the planktonic cells and mature biofilms, with significant reductions in fungal viability. Indeed, the fractional inhibitory concentration index (FICI) was lower than 0.5 for all the associations, thus indicating significant synergism of the associations with the Candida strains examined. Moreover, the concentrations of sertraline able to inhibit Candida spp. strain growth and biofilm formation significantly decreased when it was used in combination with C. verum EO for all the strains considered, with a reduction percentage in the amount of each associated component ranging from 87.5% to 97%. [ABSTRACT FROM AUTHOR]

The hepatitis C virus (HCV) is a major hepatotropic virus that affects humans with increased risk of developing hepatocellular carcinoma. The bovine viral diarrhea virus (BVDV) causes abortion, calf mortality and poor reproductive performance in cattle. Due the difficulties of in vitro cultivation for HCV, BVDV has been used as surrogate for in vitro assessment of the efficacy of antivirals. Essential oils (EOs) display antiviral and virucidal activity on several viral pathogens. In this study, the virucidal activity of five EOs, Salvia officinalis L. EO (SEO), Melissa officinalis L. EO (MEO), Citrus lemon EO (LEO), Rosmarinus officinalis L. EO (REO) and Thymus vulgaris L. EO (TEO) against BVDV was evaluated in vitro at different concentrations for several time contacts. MEO and LEO were able to considerably inactivate BVDV with a time- and dose-dependent fashion. MEO and LEO at the highest concentrations decreased viral titer by 2.00 and 2.25 log10 TCID50/50 μL at 8 h contact time, respectively. SEO, REO and TEO displayed mild virucidal activity at the highest concentrations for 8 h contact times. In this study, the virucidal efficacies of MEO and LEO against BVDV were observed regardless of compound concentration and contact time. Further studies are needed to confirm the potential use of MEO and LEO as surface disinfectants. [ABSTRACT FROM AUTHOR]

Parkinson's disease (PD) is a prevalent neurodegenerative disorder, primarily associated with dopaminergic neuron depletion in the Substantia Nigra. Current treatment focuses on compensating for dopamine (DA) deficiency, but the blood–brain barrier (BBB) poses challenges for effective drug delivery. Using differentiated SH-SY5Y cells, we investigated the co-administration of DA and the antioxidant Grape Seed Extract (GSE) to study the cytobiocompability, the cytoprotection against the neurotoxin Rotenone, and their antioxidant effects. For this purpose, two solid lipid nanoparticle (SLN) formulations, DA-co-GSE-SLNs and GSE-ads-DA-SLNs, were synthesized. Such SLNs showed mean particle sizes in the range of 187–297 nm, zeta potential values in the range of −4.1–−9.7 mV, and DA association efficiencies ranging from 35 to 82%, according to the formulation examined. The results showed that DA/GSE-SLNs did not alter cell viability and had a cytoprotective effect against Rotenone-induced toxicity and oxidative stress. In addition, this study also focused on the evaluation of Alpha-synuclein (aS) levels; SLNs showed the potential to modulate the Rotenone-mediated increase in aS levels. In conclusion, our study investigated the potential of SLNs as a delivery system for addressing PD, also representing a promising approach for enhanced delivery of pharmaceutical and antioxidant molecules across the BBB. [ABSTRACT FROM AUTHOR]

(1) Background: DA-Gelucire® 50/13-based solid lipid nanoparticles (SLNs) administering the neurotransmitter dopamine (DA) and the antioxidant grape-seed-derived proanthocyanidins (grape seed extract, GSE) have been prepared by us in view of a possible application for Parkinson's disease (PD) treatment. To develop powders constituted by such SLNs for nasal administration, herein, two different agents, namely sucrose and methyl-β-cyclodextrin (Me-β-CD), were evaluated as cryoprotectants. (2) Methods: SLNs were prepared following the melt homogenization method, and their physicochemical features were investigated by Raman spectroscopy, Scanning Electron Microscopy (SEM), atomic force microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). (3) Results: SLN size and zeta potential values changed according to the type of cryoprotectant and the morphological features investigated by SEM showed that the SLN samples after lyophilization appear as folded sheets with rough surfaces. On the other hand, the AFM visualization of the SLNs showed that their morphology consists of round-shaped particles before and after freeze-drying. XPS showed that when sucrose or Me-β-CD were not detected on the surface (because they were not allocated on the surface or completely absent in the formulation), then a DA surfacing was observed. In vitro release studies in Simulated Nasal Fluid evidenced that DA release, but not the GSE one, occurred from all the cryoprotected formulations. Finally, sucrose increased the physical stability of SLNs better than Me-β-CD, whereas RPMI 2650 cell viability was unaffected by SLN-sucrose and slightly reduced by SLN-Me-β-CD. (4) Conclusions: Sucrose can be considered a promising excipient, eliciting cryoprotection of the investigated SLNs, leading to a powder nasal pharmaceutical dosage form suitable to be handled by PD patients. [ABSTRACT FROM AUTHOR]

Systemic fungal infections have risen in recent decades and most of them are caused by Candida species, which are becoming increasingly resistant to conventional antifungal drugs. Biofilm production has been considered the most common growth form of Candida cells and is associated with a high level of antifungal resistance. At present, international research reports on the antifungal activity of non-traditional antimicrobial drugs and their potential use against life-threatening resistant fungal infections. Indeed, drug repurposing has led to the consideration of well-known compounds as a last-line therapy. The goal of this work is to evaluate the potential synergistic antifungal biofilm activity of new combinations between diclofenac sodium salt (DSS), a widely used non-steroidal anti-inflammatory drug (NSAID), with the essential oils (EOs) of Mentha piperita, Pelargonium graveolens, and Melaleuca alternifolia, whose antifungal activity has been well documented over the years. The in vitro antifungal activity of DSS and EOs was determined on different Candida strains. Susceptibility testing and the synergism of DSS and EOs versus biofilm cells was performed by using the broth microdilution assay and checkerboard methods. Minimum inhibitory concentrations (sMIC50) of DSS alone ranged from 1.25 to 2.05 mg/mL for all the strains considered. These values significantly decreased when the drug was used in combination with the EOs. The fractional inhibitory concentration index (FICI) was lower than 0.5 for almost all the associations, thus indicating a significant synergism, particularly for the DSS–Pelargonium graveolens combination towards the Candida strains examined. These preliminary results show that the combination of the EOs with DSS improves the antifungal activity on all the tested Candida strains, significantly lowering the concentrations of the components used and thus allowing any toxic effects to be overcome. [ABSTRACT FROM AUTHOR]

Metabolic syndrome (MS) is a growing disorder affecting thousands of people worldwide, especially in industrialised countries, increasing mortality. Oxidative stress, hyperglycaemia, insulin resistance, inflammation, dysbiosis, abdominal obesity, atherogenic dyslipidaemia and hypertension are important factors linked to MS clusters of different pathologies, such as diabesity, cardiovascular diseases and neurological disorders. All biochemical changes observed in MS, such as dysregulation in the glucose and lipid metabolism, immune response, endothelial cell function and intestinal microbiota, promote pathological bridges between metabolic syndrome, diabesity and cardiovascular and neurodegenerative disorders. This review aims to summarise metabolic syndrome's involvement in diabesity and highlight the link between MS and cardiovascular and neurological diseases. A better understanding of MS could promote a novel strategic approach to reduce MS comorbidities. [ABSTRACT FROM AUTHOR]

We have already formulated solid lipid nanoparticles (SLNs) in which the combination of the neurotransmitter dopamine (DA) and the antioxidant grape-seed-derived proanthocyanidins (grape seed extract, GSE) was supposed to be favorable for Parkinson's disease (PD) treatment. In fact, GSE supply would reduce the PD-related oxidative stress in a synergic effect with DA. Herein, two different methods of DA/GSE loading were studied, namely, coadministration in the aqueous phase of DA and GSE, and the other approach consisting of a physical adsorption of GSE onto preformed DA containing SLNs. Mean diameter of DA coencapsulating GSE SLNs was 187 ± 4 nm vs. 287 ± 15 nm of GSE adsorbing DA-SLNs. TEM microphotographs evidenced low-contrast spheroidal particles, irrespective of the SLN type. Moreover, Franz diffusion cell experiments confirmed the permeation of DA from both SLNs through the porcine nasal mucosa. Furthermore, fluorescent SLNs also underwent cell-uptake studies by using flow cytometry in olfactory ensheathing cells and neuronal SH-SY5Y cells, evidencing higher uptake when GSE was coencapsulated rather than adsorbed onto the particles. [ABSTRACT FROM AUTHOR]

The indiscriminate use of antimicrobials in poultry farms is linked to the increase in multi-resistant bacteria. Accordingly, based on the antimicrobial properties of Thyme Essential Oil (TEO), the present study evaluated the effects of TEO on the reduction of common microbial contaminants and Salmonella on poultry litter. A litter bulk sample was collected in a broiler farm and qualitative/quantitative investigations identified Escherichia coli and Mammaliicoccus lentus. The experimental contamination with Salmonella Derby wild strain was also performed. All pathogens showed phenotypic and genotypic resistance to different classes of antibiotics. The litter, split in different units, was treated with aqueous solutions of TEO at different concentrations (5% to 1.25%), demonstrating its effectiveness in reducing the total number of bacteria. The strongest antibacterial action was observed at the lowest concentration against Enterobacteriaceae, with a growth reduction compared to the positive control of 73.3% and 77.8% against E. coli and Salmonella Derby, respectively, while towards M. lentus the reduction was 50%. Our data confirm the antimicrobial activity of TEO and suggest its possible application for the treatment of poultry litter as an effective and natural approach for the prevention of diseases caused by the most common bacteria that colonize poultry farms, counteracting the onset of antibiotic resistance. [ABSTRACT FROM AUTHOR]

Norovirus (NoV) is regarded as a common cause of acute gastrointestinal illness worldwide in all age groups, with substantial morbidity across health care and community settings. The lack of in vitro cell culture systems for human NoV has prompted the use of cultivatable caliciviruses (such as feline calicivirus, FCV, or murine NoV) as surrogates for in vitro evaluation of antivirals. Essential oils (EOs) may represent a valid tool to counteract viral infections, particularly as food preservatives. In the present study, the virucidal efficacy of lemon EO (LEO) against FCV was assessed in vitro. The gas chromatography hyphenated with mass spectrometry (GC/MS) technique was used to reveal the chemical composition of LEO. The following small molecules were detected as major components of LEO: limonene (53%), β-pinene (14.5%), γ-terpinene (5.9%), citral (3.8%), α-pinene (2.4%), and β-thujene (1.94%). LEO at 302.0 μg/mL, exceeding the maximum non cytotoxic limit, significantly decreased viral titre of 0.75 log10 TCID50/50 μL after 8 h. Moreover, virucidal activity was tested using LEO at 3020.00 μg/mL, determining a reduction of viral titre as high as 1.25 log10 TCID50/50 μL after 8 h of time contact. These results open up perspectives for the development of alternative prophylaxis approaches for the control of NoV infection. [ABSTRACT FROM AUTHOR]

The spread of extended-spectrum β-lactamase-producing Escherichia coli and methicillin-resistant Staphylococcus aureus has caused a reduction in antibiotic effectiveness and an increase in mortality rates. Essential oils (EOs), known for their therapeutic efficacy, can be configured as novel broad-spectrum biocides. Accordingly, the bacteriostatic–bactericidal activity of Citrus Lemon (LEO), Pinus Sylvestris (PEO), Foeniculum Vulgaris (FEO), Ocimum Basilicum (BEO), Melissa Officinalis (MEO), Thymus Vulgaris (TEO), and Zingiber Officinalis Rosc. (GEO), at concentrations ranging from 1.25 to 40% (v/v), were tested in vitro against different E. coli and S. aureus strains using minimal inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs). The chemical compositions of the EOs were analyzed using GC/MS. The major components of all seven tested oils were limonene, α-pinene, anethole, estragole, citral, thymol, and zingiberene, respectively. We found that the bacteriostatic–bactericidal activity of the EOs was related to their chemotypes and concentrations, as well as the strain of the bacteria. A dose–effect correlation was found when testing GEO against S. aureus strains, whilst FEO was found to have no activity regardless of concentration. PEO, MEO, and BEO were found to have bactericidal effect with a MIC and MBC of 1.25% (v/v) against S. aureus strains, and LEO was found to have values of 1.25% (v/v) and 5% (v/v) against ATCC and clinical isolate, respectively. Interestingly, the antimicrobial activity of TEO was not related to oil concentration and the complete inhibition of growth across all E. coli and S. aureus was observed. Although preliminary, our data demonstrate the efficacy of EOs and pave the way for further investigations on their potential synergistic use with traditional drugs in the human and veterinary fields. [ABSTRACT FROM AUTHOR]

The worldwide scenario of antibiotic resistance and the falling number of funds for the development of novel antibiotics have led research efforts toward the study of specific cost-effective strategies aimed at discovering drugs against microbial infections. Among the potential options, drug repositioning, which has already exhibited satisfactory results in other medical fields, came out as the most promising. It consists of finding new uses for previously approved medicines and, over the years, many "repurposed drugs" displayed some encouraging in vitro and in vivo results beyond their initial application. The principal theoretical justification for reusing already existing drugs is that they have known mechanisms of action and manageable side effects. Reuse of old drugs is now considered an interesting approach to overcome the drawbacks of conventional antibiotics. The purpose of this review is to offer the reader a panoramic view of the updated studies concerning the repositioning process of different classes of non-antibiotic drugs in the antimicrobial field. Several research works reported the ability of some non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants, antipsychotics, and statins to counteract the growth of harmful microorganisms, demonstrating an interesting winning mode to fight infectious diseases caused by antimicrobial resistant bacteria. [ABSTRACT FROM AUTHOR]

A technique based on liquid chromatography has been developed to facilitate studies of enantioselectivity in penicillin G acylase (PGA)-catalyzed hydrolysis of some 2-aryloxyalkanoic acid methyl esters and isosteric analogues. PGA was covalently immobilized on an aminopropyl monolithic silica support to create an immobilized HPLC-enzyme reactor. Two sets of experimental data were drawn to calculate the enantioselectivity (E) of the kinetically controlled enantiomer-differentiating reaction, the degree of substrate conversion and the enantiomeric excess of the product. The developed enzymatic reactor was coupled through a switching valve to an achiral analytical column for separation and quantitation of the hydrolysis products. The enantiomeric excess was determined off-line on a PGA-chiral stationary phase. In this way, highly precise E values were determined. A computational study related to the hydrolysis of the considered racemic esters was also carried out in order to unambiguously clarify both the substrate specificity and the enantioselectivity displayed by PGA.

Mentha piperita L. essential oil (EO) is employed for external use as antipruritic, astringent, rubefacient and antiseptic. Several studies demonstrated its significant antiviral, antifungal and antibacterial properties. The aim of this work is the study of the synergistic effects of M. piperita EO with antibacterials and antifungals that are widely available and currently prescribed in therapies against infections. The observed strong synergy may constitute a potential new approach to counter the increasing phenomenon of multidrug resistant bacteria and fungi. In vitro efficacy of the association M. piperita EO/drugs was evaluated against a large panel of Gram-positive and Gram-negative bacteria and yeast strains. The antimicrobial effects were studied by checkerboard microdilution method. The synergistic effect of M. piperita EO with gentamicin resulted in a strong growth inhibition for all the bacterial species under study. The synergistic effect observed for M. piperita EO and antifungals was less pronounced. [ABSTRACT FROM AUTHOR]

Seven uncommon types of essential oils obtained from Pinus nigra, Hyssopus officinalis, Sison amomum, Smyrnium olusatrum, Helosciadium nodiflorum, Pelargonium graveolens and Vepris macrophylla were tested against a panel of thirty bacterial strains that cause serious infectious diseases. Among these bacterial species, the most dangerous for human health were five documented multi-drug-resistant strains belonging to the Acinetobacter and Klebsiella genera and derived from clinical isolation. The chemical composition of essential oils was achieved by GC-MS analysis, whereas the antibacterial efficacy was evaluated by the microdilution technique according to CLSI document M7-A9. The Vepris macrophylla essential oil, which contains geranial (33.2%), neral (23.1%) and citronellol (14.5%), exhibited the strongest inhibition against the multi-resistant strains A. baumannii, K. pneumoniae and S. aureus, with MIC values of 4.1, 2.05 and 4.1 mg/ml, respectively. [ABSTRACT FROM AUTHOR]

Research was conducted to examine the enantioselective catalytic oxidation of (arylthio)- or (alkylthio)methylphosphonates as a route to enantiomeric pure aryl alkyl or dialkyl sulfoxides. The successful oxidation reaction produced the corresponding diethyl (methylsulfinyl)methylphosphonate, diethyl (ethylsulfinyl)methylphosphonate and diethyl (phenylsulfinyl)methylphosphonate in ee values up to >98%. 1H NMR techniques were used to determine the ee values of the products through the use of (S)-BINOL as a chiral solvating agent.

A novel class of antibacterial and antifungal agents is here identified by means of dockings and virtual screening techniques. Biological data proved the initial effort, formulated on the structure similarity of nuclear receptors binders with known quinolones or thiazole derivatives, to reposition PPARs agonists as likely bacterial type II topoisomerases inhibitors. [ABSTRACT FROM AUTHOR]

Some aminophenyl benzyl sulfides or benzyl pyridyl sulfides were asymmetrically oxidized withtert-butyl hydroperoxide in the presence of a complex between titaniumi-propoxide and (S, S)-hydrobenzoin, an oxidation system that works particularly well with a vast set of aryl benzyl sulfides. Notwithstanding the presence of nitrogen-containing moieties that, in principle, could interfere with the correct co-ordination of the sulfide to the metal center, satisfactory levels of enantioselectivity (up to 78%) were measured for this oxidation process. [ABSTRACT FROM AUTHOR]

The supply of nutrients, such as antioxidant agents, to fish cells still represents a challenge in aquaculture. In this context, we investigated solid lipid nanoparticles (SLN) composed of a combination of Gelucire® 50/13 and Precirol® ATO5 to administer a grape seed extract (GSE) mixture containing several antioxidant compounds. The combination of the two lipids for the SLN formation resulted in colloids exhibiting mean particle sizes in the range 139–283 nm and zeta potential values in the range +25.6–43.4 mV. Raman spectra and X-ray diffraction evidenced structural differences between the free GSE and GSE-loaded SLN, leading to the conclusion that GSE alters the structure of the lipid nanocarriers. From a biological viewpoint, cell lines from gilthead seabream and European sea bass were exposed to different concentrations of GSE-SLN for 24 h. In general, at appropriate concentrations, GSE-SLN increased the viability of the fish cells. Furthermore, regarding the gene expression in those cells, the expression of antioxidant genes was upregulated, whereas the expression of hsp70 and other genes related to the cytoskeleton was downregulated. Hence, an SLN formulation containing Gelucire® 50/13/Precirol® ATO5 and GSE may represent a compelling platform for improving the viability and antioxidant properties of fish cells. [ABSTRACT FROM AUTHOR]

CIC-Ka and CIC-Kb Cl- channels are pivotal for renal salt reabsorption and water balance. There is growing interest in identifying ligands that allow pharmacological interventions aimed to modulate their activity. Starting from available ligands, we followed a rational chemical strategy, accompanied by computational modeling and electrophysiological techniques, to identify the molecular requisites for binding to a blocking or to an activating binding site on CIC-Ka. The major molecular determinant that distinguishes activators from blockers is the level of planarity of the aromatic portions of the molecules: only molecules with perfectly coplanar aromatic groups display potentiating activity. Combining several molecular features of various CLC-K ligands. we discovered that phenyl-benzofuran carboxylic acid derivatives yield the most potent CIC-Ka inhibitors so far described (affinity <10 μM). The increase in affinity compared with 3-phenyl-2-p-chlorophenoxy-propionic acid (3-phenyl-CPP) stems primarily from the conformational constraint provided by the phenyl-benzofuran ring. Several other key structural elements for high blocking potency were identified through a detailed structure-activity relationship study. Surprisingly, some benzofuran-based drugs inhibit did-Kb with a similar affinity of <10 μM, thus representing the first inhibitors for this CLC-K isoform identified so far. Based on our data, we established a pharmacophore model that will be useful for the development of drugs targeting CLC-K channels. [ABSTRACT FROM AUTHOR]

Discusses the structure of propionic 2-(p-chlorophenoxy)propionic acid (CPP) analogues for activity in the skeletal muscle chloride conductance of rats. Independent modification of CCP structure leading to a decrease of chloride blocking activity; Identification of four molecular determinants pivotal to the interaction with the binding site on muscle CLC-1 channels.

The consumption of meals prepared, packaged, and consumed inside and outside the home is increasing globally. This is a result of rapid changes in lifestyles as well as innovations in advanced food technologies that have enabled the food industry to produce more sustainable and healthy fresh packaged convenience foods. This paper presents an overview of the technologies and compatible packaging systems that are designed to increase the shelf-life of foods prepared by cook–chill technologies. The concept of shelf-life is discussed and techniques to increase the shelf life of products are presented including active packaging strategies. [ABSTRACT FROM AUTHOR]

Triclocarban (TCC) is a polychlorinated, aromatic, antimicrobial agent commercially used since the 1950s in personal care products for the prevention of spoilage and infections. Humans are frequently exposed to TCC due to its widespread use, leading to its substantial release into the aquatic environment. With the recent ban of TCC from some personal care products, implemented in 2016, many replacement antimicrobial compounds have been studied by researchers. Herein, we report the synthesis and biological activity of a series of diarylureas, analogues of TCC that bear the benzothiazole nucleus as one of the two aryl moieties. Among the studied compounds, 2bF and 2eC showed the highest antimicrobial activity against Staphylococcus aureus, being also more active than TCC, with MIC values of 8 µg/mL versus 16 µg/mL of TCC. Moreover, compound 2bB was much more active than TCC against Enterococcus faecalis, a Gram-positive bacterium that is, unfortunately, strongly responsible for nosocomial infections. Finally, interesting results were found for compound 2bG that, even though less active than the others, exerts an interesting bactericidal action. [ABSTRACT FROM AUTHOR]

According to recent studies, Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) have shown a good antimicrobial and antifungal activity. Their association with essential oils (EOs) could be useful for the treatment of infections caused by Candida spp. The aim of this studyis to evaluate the synergistic antifungal activity of new combinations between Diclofenac Sodium Salt (DSS), a widely used NSAID, with EOs of Mentha × piperita, Pelargonium graveolens and Melaleuca alternifolia. The in-vitro antifungal activity was determined on different Candida strains. The determination of the chemical composition of EOs was carried out by gaschromatography-massspectrometry (GC-MS). Susceptibility testing of planktonic cells was performed by using the broth microdilution assay and checkerboard methods. Minimum Inhibitory Concentrations (MIC) of DSS was in a range from 1.02 to 2.05 μg/mL reaching a MIC value of 0.05 μg/mL when combined with Pelargonium graveolens (FICI = 0.23–0.35) or Menthapiperita (FICI = 0.22–0.30) EOs. These preliminary results show thatthe combination of the EOs with DSS improves the antifungal activity on all the tested Candida strains. [ABSTRACT FROM AUTHOR]

In recent years, the increase of bacteria antibiotic- resistance has been a severe problem for public health. A useful solution could be to join some phytochemicals naturally present in essential oils (EOs) to the existing antibiotics, with the aim to increase their efficacy in therapies. According to in vitro studies, EOs and their components could show such effects. Among them, we studied the activity of Cinnammonum zeylanicum, Mentha piperita, Origanum vulgare, and Thymus vulgaris EOs on bacterial biofilm and their synergism when used in association with some common antibiotics such as norfloxacin, oxacillin, and gentamicin. The chemical composition of EOs was determined using gas chromatography (GC) coupled with mass spectrometry (MS) techniques. The EOs drug efficacy was evaluated on four different strains of Gram-positive bacteria forming biofilms. The synergistic effects were tested through the chequerboard microdilution method. The association EOs-antibiotics showed a strong destruction of the biofilm growth of the four bacterial species considered. The interaction of norfloxacin with EOs was the most effective in all the tested combinations against the strains object of this study. These preliminary results suggest the formulation of a new generation of antimicrobial agents based on a combination of antimicrobial compounds with different origin. [ABSTRACT FROM AUTHOR]

A multistep gram-scale synthesis of (S)-ethyl 2-(tert-butoxycarbonylamino)-3-(2-iodo-4,5-methylenedioxyphenyl)propanoate (2) has been developed. The title compound was prepared starting from commercially available l-DOPA which was O- and N-protected before undergoing iodination by CF3CO2Ag/I2. The structure of the target compound was confirmed using IR, 1H-NMR, 13C-NMR, 2D (COSY, HSQC) NMR spectroscopy, as well as ESI-MS and HRMS. [ABSTRACT FROM AUTHOR]