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Background: Laurelia sempervirens, better known as Chilean laurel, is endemic to Chile. For many years, the leaves and branches of this plant have been popularly used as medicinal agents. However, its antifungal properties and antibiofilm activity against bacterial strains have not been studied. Objectives: To determine antibiofilm and antimicrobial properties of Chilean laurel essential oil on human pathogenic strains. Methods: The antifungal and antibacterial activities of Chilean laurel essential oil were evaluated through the agar diffusion method, and its minimum inhibitory concentration was determined using the standard microdilution method. Antibiofilm activity was examined based on the formation and disruption of bacterial biofilms and evidenced by the crystal violet technique. Results: The results showed important antimicrobial activity against human pathogenic yeast strains, and the minimum inhibitory concentration of Chilean laurel essential oil was 64 µg mL-1 against Candida albicans. The essential oil also showed an important inhibitory effect against the formation of biofilms produced by Staphylococcus aureus, since it inhibited the formation of biofilms by over 50% at the concentration of 64 µg mL-1. With increasing the essential oil’s concentration to 128 µg mL-1, its antibiofilm activity increased by 60%. Conclusions: These results approve the domestic use of Chilean laurel essential oil as an antimicrobial agent and provide knowledge about the antibiofilm and antifungal properties of L. sempervirens.

Background and Objectives: Haplopappus multifolius Phil. Ex Reiche and Haplopappus taeda Reiche are medicinal shrubs native to Chile and are popularly known as "Bailahuén". Regularly, this plant is used for liver, digestive and renal affections, as well as colds and the cleaning of infected wounds. The aim of the study was to identify the responsible compounds for the antimicrobial activity of H. multifolius and H. taeda. Materials and Methods: Infusions and ethanolic extracts of H. taeda and H. multifolius were analysed by thin-layer chromatography bioautography (TLC-B) to determine the compounds responsible for the antimicrobial activity against Gram-positive and Gram-negative bacterial strains and yeasts of Bailahuén. Finally, the minimum inhibitory concentration (MIC) of pure compounds isolated was determinate. Results: Extract of Bailahuén had activity only against Gram-positive bacterial strains and this activity was associated with aesculetin, 18-acetoxy-cis-cleroda-3,13E-dien-15-oic acid and aromadendrin-7-methyl ether compounds. Conclusion: H. multifolius and H. taeda have antibacterial capacity on different species of Gram-positive bacteria pathogenic for humans.

An efficient and novel step-by-step synthesis of poly(amidoamine) (PAMAM) dendrimers by the divergent and method using ultrasound irradiation at room temperature is presented here. The results were compared with the conventional and microwave-assisted approach synthesis. The mass spectra analysis showed a major consumption of PAMAM G -0.5 (m/z 403.5) to obtain PAMAM G0, with an intensity below 10% by ultrasonic synthesis to difference of 30 and 50% of intensity in conventional and microwave synthesis, respectively. Also, a plausible mechanism is proposal in order to understand the byproducts formation in conventional and microwave synthesis, thus, the formation of defects occurs for PAMAM G0-arm cleave through of an alpha-beta breakdown of a betaine adduct generated in situ, decreasing the reaction yields.The structural analyses of the samples were carried out using FT-IR and NMR spectroscopic, and (ESI-MS) spectrometric analysis. The results showed that the ultrasound-assisted synthesis reduces the reaction time, prevents the formation of defective structures, and increases reaction yields.

Currently, special emphasis is being given to the design and fabrication of antibacterial nanocomposite hydrogels for wound dressing applications. Herein, we report the synthesis and characterization of hydroxypropyl methylcellulose (HPMC) reinforced with HPMC capped copper nanoparticles (HCu NPs) based nanocomposite hydrogel films (NHFs). Spherical nanostructures of HCu NPs (∼40 nm) were achieved by facile precipitation technique using ascorbic acid as a nucleating agent and subsequently made their NHFs via solution casting method. Spectral, thermal and structural characteristics of the developed materials were carried out. Antibacterial activity of the resultant NHFs showed the MIC and MBC values of 350 and 1400 μg/mL for S. aureus, and 500 and 2000 μg/mL for E. coli, respectively. These results conveyed that the HCu NPs incorporated HPMC NHFs can be used effectively in antibacterial applications.

Fumonisins are a group of mycotoxins found in various foods whose consumption is known to be harmful for human health. In this study, we evaluated the ability of three polymers (Polyvinylpolypyrrolidone, PVPP; a resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate, PVP-DEGMA-TAIC; and poly(acrylamide-co-ethylene glycol-dimethacrylate), PA-EGDMA) to remove fumonisin B1 (FB1) and fumonisin B2 (FB2) from model solutions and red wine. Various polymer concentrations (1, 5 and 10mgmL-1) and contact times (2, 8 and 24h) were tested, with all polymers exhibiting fumonisin removal capacities (monitored by LC-MS). The impact of all polymers on polyphenol removal was also assessed. PA-EGDMA showed to be the most promising polymer, removing 71% and 95% of FB1, and FB2, respectively, with only a 22.2% reduction in total phenolics.

In this study, a versatile synthesis of silver nanoparticles of well-defined size by using hydrogels as a template and stabilizer of nanoparticle size is reported. The prepared hydrogels are based on polyvinyl alcohol and maleic acid as crosslinker agents. Three hydrogels with the same nature were synthesized, however, the crosslinking degree was varied. The silver nanoparticles were synthesized into each prepared hydrogel matrix achieving three significant, different-sized nanoparticles that were spherical in shape with a narrow size distribution. It is likely that the polymer network stabilized the nanoparticles. It was determined that the hydrogel network structure can control the size and shape of the nanoparticles. The hydrogel/silver nanohybrids were characterized by swelling degree, Thermal Gravimetric Analysis (TGA), Fourier Transform Infrared (FT-IR), Scanning Electron Microscopy (SEM) and Transmission Electron Microscope (TEM). Antibacterial activity against Staphylococcus aureus was evaluated, confirming antimicrobial action of the encapsulated silver nanoparticles into the hydrogels.

A strain of Shigella flexneri producing bacteriocin was isolated from a patient with diarrhea. The main objective of this study was to isolate and partially characterize the bacteriocin. The producing microorganism was identified using biochemical, serological, and molecular methods. The lethal activity of the S. flexneri strain was studied using the drop method. This bacterial strain showed activity against different strains of E. coli and B. fragilis. Using immunological techniques, it was determined that S. flexneri belongs to serotype 2a, and by PCR, the presence of the ipaH plasmid was determined. By chromatographic techniques, it was determined that the bacteriocin is a peptide of high purity with a molecular weight of 66294.094 Da. The amino acid composition and sequence were determined by the Edman reaction, and a sequence of 619 amino acid residues was obtained. Only in five positions of this sequence, the amino acid glutamine changed to glutamic acid with respect to colicin U produced by S. boydii. From an ecological point of view, it could be assumed that SF1 bacteriocin contributes to eliminate some members of the normal microbiota of the human intestine, facilitating colonization and then producing the invasion process that characterizes the pathogenicity of Shigella.

A strain of Shigella flexneri producing bacteriocin was isolated from a patient with diarrhea. The main objective of this study was to isolate and partially characterize the bacteriocin. The producing microorganism was identified using biochemical, serological, and molecular methods. The lethal activity of the S. flexneri strain was studied using the drop method. This bacterial strain showed activity against different strains of E. coli and B. fragilis. Using immunological techniques, it was determined that S. flexneri belongs to serotype 2a, and by PCR, the presence of the ipaH plasmid was determined. By chromatographic techniques, it was determined that the bacteriocin is a peptide of high purity with a molecular weight of 66294.094 Da. The amino acid composition and sequence were determined by the Edman reaction, and a sequence of 619 amino acid residues was obtained. Only in five positions of this sequence, the amino acid glutamine changed to glutamic acid with respect to colicin U produced by S. boydii. From an ecological point of view, it could be assumed that SF1 bacteriocin contributes to eliminate some members of the normal microbiota of the human intestine, facilitating colonization and then producing the invasion process that characterizes the pathogenicity of Shigella.

This study describes the in-silico rational design, synthesis and evaluation of cross-linked polyvinyl alcohol hydrogels containing γ-cyclodextrin (γ-CDHSAs) as platforms for the sustained release of prednisone (PDN). Through in-silico studies using semi-empirical quantum mechanical calculations, the effectiveness of 20 dicarboxylic acids to generate a specific cross-linked hydrogel capable of supporting different amounts of γ-cyclodextrin (γ-CD) was evaluated. According to the interaction energies calculated with the in-silico studies, the hydrogel made from PVA cross-linked with succinic acids (SA) was shown to be the best candidate for containing γ-CD. Later, molecular dynamics simulation studies were performed in order to evaluate the intermolecular interactions between PDN and three cross-linked hydrogel formulations with different proportions of γ-CD (2.44%, 4.76% and 9.1%). These three cross-linked hydrogels were synthesized and characterized. The loading and the subsequent release of PDN from the hydrogels were investigated. The in-silico and experimental results showed that the interaction between PDN and γ-CDHSA was mainly produced with the γ-CDs linked to the hydrogels. Thus, the unique structures and properties of γ-CDHSA demonstrated an interesting multiphasic profile that could be utilized as a promising drug carrier for controlled, sustained and localized release of PDN.

Ochratoxin A (OTA) is a mycotoxin produced by filamentous-type fungi that contaminates a wide variety of foods and beverages such as wines. In these trials, we evaluated the capacity of the following polymers for the removal of OTA from acidic model solutions and red wine: polyvinylpolypyrrolidone (PVPP), resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate (PVP-DEGMA-TAIC), and poly(acrylamide-co-ethylene glycol-dimethacrylate) (PA-EGDMA). In acidic model solution, PVP-DEGMA-TAIC and PA-EGDMA polymers removed up to 99.9% of OTA, but their trapping capacity was highly reduced by the presence of competing phenolic substances (i.e. gallic acid and 4-methylcathecol). In real red wine, PA-EGDMA polymer showed the most promising results, with more than 68.0% OTA removal and less than 14.0% reduction in total phenolic. Finally, computational chemistry analyses showed that the affinity between OTA and the polymers studied would be due to Van der Waals interactions.

Volatile phenols, such as 4-ethyphenol (4-EP) and 4-ethylguaiacol (4-EG), are responsible for the “Brett character” found in wines contaminated with Brettanomyces yeast (i.e., barnyard, animal, spicy and smoky aromas). In these trials, we explore the effectiveness of polyaniline-based compounds (polyaniline emeraldin salt (PANI-ES) and polyanaline emeraldin base (PANI-EB)), for the removal of 4-EP and 4-EG from acidic model solutions and red wine. First, a screening study, performed in an acidified 12% ethanol solution, was used to optimize parameters such as contact time and the amount of polymers required to remove 4-EP and 4-EG. Then, the trapping ability of PANI agents towards 4-EP and 4-EG was evaluated in a model solution containing other wine phenolics that could potentially be trapped by PANI (i.e., gallic acid and 4-methylcatechol). The results of this trial showed that both PANI compounds were capable of removing 4-EP, 4-EG, regardless of the presence of other phenolic compounds present at a much higher concentration. Finally, the capturing ability of PANI was evaluated in a red wine sample containing 5 mg·L−1 of 4-EP, 5 mg·L−1 of 4-EG and 2.03 ± 0.02 g·L−1 of total phenolics. The results showed that PANI-EB removed significantly more 4-EP and 4-EG than PANI-ES. For instance, a treatment with 10 mg·mL−1 of PANI-EB produced a 67.8% reduction of 4-EP, 50% reduction of 4-EG and 41.38% decrease in total phenols.

Volatile phenols, such as 4-ethyphenol (4-EP) and 4-ethylguaiacol (4-EG), are responsible for the Brett character found in wines contaminated with Brettanomyces yeast (i.e., barnyard, animal, spicy and smoky aromas). In these trials, we explore the effectiveness of polyaniline-based compounds (polyaniline emeraldin salt (PANI-ES) and polyanaline emeraldin base (PANI-EB)), for the removal of 4-EP and 4-EG from acidic model solutions and red wine. First, a screening study, performed in an acidified 12% ethanol solution, was used to optimize parameters such as contact time and the amount of polymers required to remove 4-EP and 4-EG. Then, the trapping ability of PANI agents towards 4-EP and 4-EG was evaluated in a model solution containing other wine phenolics that could potentially be trapped by PANI (i.e., gallic acid and 4-methylcatechol). The results of this trial showed that both PANI compounds were capable of removing 4-EP, 4-EG, regardless of the presence of other phenolic compounds present at a much higher concentration. Finally, the capturing ability of PANI was evaluated in a red wine sample containing 5 mgL(-1) of 4-EP, 5 mgL(-1) of 4-EG and 2.03 +/- 0.02 gL(-1) of total phenolics. The results showed that PANI-EB removed significantly more 4-EP and 4-EG than PANI-ES. For instance, a treatment with 10 mgmL(-1) of PANI-EB produced a 67.8% reduction of 4-EP, 50% reduction of 4-EG and 41.38% decrease in total phenols.

We present a novel, insoluble, low-generation polyamidoamine (PAMAM)-based polymer. The monomer and polymer were characterized by fourier transform infrared spectroscopy, electrospray ionization mass spectrometry and thermogravimetric measurement, revealing that G0 acryloyl-terminated PAMAM were synthesized and polymerized using ammonium persulfate as an initiator, producing a high-density PAMAM derivative (PAMAM-HD). PAMAM-HD was tested for its ability to remove Na(I), K(I), Ca(II), Mg(II), Cu(II), Mn(II), Cd(II), Pb(II) and Zn(II) ions from acidic, neutral and basic aqueous solutions. PAMAM-HD efficiently removed metals ions from all three solutions. The greatest absorption efficiency at neutral pH was observed against Cu(II), Cd(II) and Pb(II), and the experimental data were supported by the calculated Kd values. Our data could have a significant impact on water purification by providing an inexpensive and efficient polymer for the removal of metal ions.

Fumonisins are a group of mycotoxins found in various foods whose consumption is known to be harmful for human health. In this study, we evaluated the ability of three polymers (Polyvinylpolypyrrolidone, PVPP; a resin of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate, PVP-DEGMA-TAIC; and poly(acrylamide-co-ethylene glycol-dimethacrylate), PA-EGDMA) to remove fumonisin B

This short review presents new insights on the mechanism and online monitoring using electrospray ionization tandem mass spectrometry (ESI–MS/MS) of Morita–Baylis–Hillman (MBH) reactions. MBH reactions are versatile carbon-carbon organocatalyzed bond forming reactions, making them environmentally friendly due to general organocatalysts employed. The organocatalyst behavior, which controls the transition state and thus the enantioselectivities in the obtained products, is very important in the performance of asymmetric MBH transformations. Some recent techniques and advances in asymmetric transformations are reviwed, as well as online reaction monitoring and analysis of the reaction intermediates. The mechanism accepted nowadays is also review through the insights gained from the use of ESI–MS/MS techniques.

The aim of this work was to study a fast, new, sensitive, and simple method for the chemotaxonomic classification of Chilean lichens (Teloschistes chrysophthalmus, Ramalina farinacea, Usnea pusilla, Ramalina chilensis and Stereocaulon ramulosum) using MALDI-TOF-MS and UPLC-ESI(-)-MS data. Lichens soluble proteins fingerprints were acquired by MALDI-TOF-MS and they were analyzed by chemometric (PCA). Lichens organic extracts fingerprints were obtained by UPLC-ESI(-)-MS. MALDI-TOF-MS associated with chemometric analysis was used to detect new m/z patterns of soluble proteins that were compared with Protein Data Bank of UnitPro. These data also permitted the satisfactory distinction among the families and species. UPLC-ESI(-)-MS fingerprints analyses of the organic extracts showed the presence of five major lichen compounds (atranorin, parietin, teloschistin, ramalinolic and usnic acids). In contrast to other techniques, MALDI-TOF-MS associated with chemometric analysis and UPLC-ESI(-)-MS provided a new, fast and sensitive method for chemotaxonomic characterization of lichens.

4-ethylguaiacol (4-EG) is one of the important compounds responsible for the "Brett character" (i.e. spicy and smoky aromas) found in wines contaminated with Brettanomyces yeast. In this trial, the ability of polyaniline-based materials (PANI-EB and PANI-ES) was tested as a potential fining agent for the removal of 4-EG in wine. First, a screening study was developed in order to determine the binding capacity of 4-EG by PANI materials in 12% ethanol solution. Then, the capturing ability of PANI against 4-EG was evaluated with a solution containing gallic acid (GA), 4-methyl-catechol (4-MC), in which the concentration of the phenolic compounds were maintained as in the real wine. The results obtained showed that the retention percentage varied between 0 to 100% (4-EG), 13.81% to 72.32% (GA), and 0 to 17.39% (4-MC), depending on the interaction time and amount of the PANI used. Finally, the capturing capacity of PANI-EB and PANI-ES against 4-EG was evaluated in a real win e sample containing originally 3.10 ± 0.13 mg L-1 of 4-EG and 2.55 ± 0.10 g L-1 of other total phenolic compounds. The analyses performed indicated that PANI-EB is more effective in removing 4-EG than PANI-ES, with retention percentages varying between 36 and 50%.

The search for new nano-systems for targeted biomedical applications and controlled drug release has attracted significant attention in polymer chemistry, pharmaceutics, and biomaterial science. Controlled drug delivery has many advantages over conventional drug administration, such as reduction of side effects, maintaining a stable plasma level concentration and improving the quality of life of patients. In this study, PAMAM G5 dendrimers and PAMAM G5-folic acid conjugates (PAMAM G5-FA) are synthesized and characterized by mass spectrometry (MALDI-MS). Controlled release studies at different pH values show that PAMAM G5-FA is a good candidate as a carrier for tramadol and morphine, while mathematical modeling is conducted, suggesting that the release process is governed by a diffusion mechanism. In addition, using molecular dynamics simulations, we investigate the structural and energetic properties that facilitate the encapsulation of tramadol and morphine by unmodified and functionalized PAMAM-G5 dendrimers at low, neutral and high pH. Our results correlate well with experimental data, confirming that tramadol and morphine may be encapsulated both by functionalized PAMAM dendrimers and unmodified PAMAM. Moreover, the simulations further reveal that hydrogen-bond and electrostatic interactions govern the affinity the dendrimers for both drugs. This information is envisioned to prove useful for the encapsulation of other drugs and for the design of novel functionalized dendrimers.

Volatile species with thiol functions are important contributors to the flavour of a wide variety of wine types. However, in spite of their importance, their fate during winemaking has not been fully elucidated. In this work, the iron-catalysed reaction between 3-sulfanyl-1-hexanol, catechol-containing phenolics, and sulfurous acid, under in vitro aerobic conditions was evaluated by means of electrospray ionisation mass spectrometry (ESI-MS). The results indicate that a direct addition reaction between the thiol and some of the phenolics tested, and between sulfite and some of the phenolics may occur, thus contributing evidence of a possible route of thiol losses in wines.

This short review presents new insights on the mechanism and online monitoring using electrospray ionization tandem mass spectrometry (ESI–MS/MS) of Morita–Baylis–Hillman (MBH) reactions. MBH reactions are versatile carbon-carbon organocatalyzed bond forming reactions, making them environmentally friendly due to general organocatalysts employed. The organocatalyst behavior, which controls the transition state and thus the enantioselectivities in the obtained products, is very important in the performance of asymmetric MBH transformations. Some recent techniques and advances in asymmetric transformations are reviwed, as well as online reaction monitoring and analysis of the reaction intermediates. The mechanism accepted nowadays is also review through the insights gained from the use of ESI–MS/MS techniques.