Anticandida and antibiofilm activities of extract from Schinopsis brasiliensis Engl. against Candida spp.

The pathogenic nature of infections caused by Candida spp. underscores the necessity for novel therapeutic agents. Extracts of Schinopsis brasilienses Engl are \ a promising source of agents with antifungal effects. This study aimed to assess the antifungal potential of the leaf extract of S. brasilienses. The antifungal activity was evaluated by determining the minimum inhibitory concentrations and fungicide concentrations (MIC and MFC). The antibiofilm potential was assessed by counting colony-forming units/mL. The study examined the inhibition kinetics of fungal growth and potential synergism between gallic acid or the extract and nystatin using the Checkerboard method. Cytotoxicity was evaluated through the MTT assay. The extract exhibited antifungal effect against all tested strains, with MIC and MFC ranging from 31.25-250 µg/mL. Gallic acid, the main isolated compound, displayed a MIC of 2000 µg/mL. The extract of S. brasilienses at 31.25 µg/mL inhibited the formation of biofilm by C. albicans and significantly reduced the mass of mature biofilm after 24 and 48 h (p < 0. 05). At a concentration of 125 µg/mL, the extract demonstrated significant inhibition of fungal growth after 6 hours. The combination of gallic acid or extract with nystatin did not exhibit synergistic or antagonistic effect. Furthermore, the extract did not induce cytotoxicity to a human cell line. The extract of S. brasiliensis demonstrates antifungal activity against Candida, generally exhibiting fungicidal action and capacity to inhibit biofilm formation as well as reduce mature biofilms. Additionally, the extract showed low cytotoxicity to human cells.

Anticandida and antibiofilm activities of extract from Schinopsis brasiliensis Engl. against Candida spp

Abstract The pathogenic nature of infections caused by Candida spp. underscores the necessity for novel therapeutic agents. Extracts of Schinopsis brasilienses Engl are / a promising source of agents with antifungal effects. This study aimed to assess the antifungal potential of the leaf extract of S. brasilienses. The antifungal activity was evaluated by determining the minimum inhibitory concentrations and fungicide concentrations (MIC and MFC). The antibiofilm potential was assessed by counting colony-forming units/mL. The study examined the inhibition kinetics of fungal growth and potential synergism between gallic acid or the extract and nystatin using the Checkerboard method. Cytotoxicity was evaluated through the MTT assay. The extract exhibited antifungal effect against all tested strains, with MIC and MFC ranging from 31.25-250 μg/mL. Gallic acid, the main isolated compound, displayed a MIC of 2000 μg/mL. The extract of S. brasilienses at 31.25 μg/mL inhibited the formation of biofilm by C. albicans and significantly reduced the mass of mature biofilm after 24 and 48 h (p < 0. 05). At a concentration of 125 μg/mL, the extract demonstrated significant inhibition of fungal growth after 6 hours. The combination of gallic acid or extract with nystatin did not exhibit synergistic or antagonistic effect. Furthermore, the extract did not induce cytotoxicity to a human cell line. The extract of S. brasiliensis demonstrates antifungal activity against Candida, generally exhibiting fungicidal action and capacity to inhibit biofilm formation as well as reduce mature biofilms. Additionally, the extract showed low cytotoxicity to human cells.

E-liquid alters oral epithelial cell function to promote epithelial to mesenchymal transition and invasiveness in preclinical oral squamous cell carcinoma.

The gaining popularity of tobacco and nicotine delivery products, such as electronic cigarettes (e-cigarettes) being perceived as relatively safe is of a medical concern. The long-term safety of these new products remains uncertain for oral health. In this study, in vitro effects of e-liquid were assessed in a panel of normal oral epithelium cell lines (NOE and HMK), oral squamous cell carcinoma (OSCC) human cell lines (CAL27 and HSC3), and a mouse oral cancer cell line (AT84) using cell proliferation, survival/cell death, and cell invasion assays. In addition, signaling pathways underlying the pro-invasive activity of e-cigarettes were evaluated by gene and protein expression analysis. We demonstrated that e-liquid promotes proliferation and anchorage-independent growth of OSCC and induces morphological changes associated with enhanced motility and invasive phenotypes. Furthermore, e-liquid-exposed cells express significantly reduced cell viability, regardless of e-cigarette flavour content. At the gene expression level, e-liquid induces changes in gene expression consistent with epithelial to mesenchymal transition (EMT) revealed by reduced expression of cell epithelial markers such as E-cadherin and enhanced expression of mesenchymal proteins like vimentin and B-catenin seen both in OSCC cell lines and normal oral epithelium cells. In summary, the ability of e-liquid to induce proliferative and invasive properties along the activation of the EMT process can contribute to the development of tumorigenesis in normal epithelial cells and promote aggressive phenotype in pre-existing oral malignant cells.

Antimicrobial effect and the mechanical and surface properties of a self-disinfecting and a chlorhexidine-incorporated Type IV dental stone.

STATEMENT OF PROBLEM: Stone casts are subject to contamination, but whether disinfectants incorporated into the stone are effective is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the antimicrobial activity and the mechanical and surface properties of self-disinfecting gypsum (SDG) and gypsum mixed with 2% chlorhexidine (GCHX). MATERIAL AND METHODS: Antimicrobial action was evaluated using the diffusion-disk technique on Streptococcus aureus and Candida albicans 1 hour and 24 hours after pouring the gypsum. The groups were SDG, GCHX, a positive control (PC) of gypsum mixed with distilled water, and a negative control (NC) of filter paper disk soaked with 2% chlorhexidine; n=8. Inhibition halos were measured using the ImageJ software program and statistically analyzed using the repeated measures mixed ANOVA with time×group interaction. Compressive strength (CS) in MPa and surface roughness (SR) in µm (parameters: Ra - roughness average; and Sa - 3-dimensional (3D) arithmetic mean of the surface profile) tests were performed to characterize the specimens (evaluated groups: SDG, GCHX, and PC; n=10). CS data were analyzed by a 2-way ANOVA with time×group interaction, and SR data by a 1-way ANOVA (α=.05). RESULTS: For S aureus, there were differences between GCHX and SDG at 1 hour and 24 hours (P<.05), but no significant differences were found for C albicans (P>.05). GCHX was better than PC, except for C albicans, and showed a reduction in CS when compared with PC and SDG (P<.05) at all time intervals. The SR of GCHX increased (Ra:1.76, Sa:2.08) when compared with PC (Ra:0.89, Sa:1.12) and SDG (Ra:1.03, Sa:1.35) (Ra: P<.004 and Sa: P<.001). CONCLUSIONS: The antimicrobial activity of GCHX against S aureus was better than that of SDG, but neither had an effect against C albicans. As for CS and SR, GCHX presented a decrease in properties when compared with PC and SDG but was within the American Dental Association #25 specification values.

Implications and Emerging Therapeutic Avenues of Inflammatory Response in HPV+ Head and Neck Squamous Cell Carcinoma.

Head and neck squamous cell carcinomas (HNSCC) are a heterogeneous group of malignancies which have shown exponential incidence in the last two decades especially due to human papillomavirus (HPV) infection. The HPV family comprises more than 100 types of viruses with HPV16 and HPV18 being the most prevalent strains in HNSCC. Literature data reveal that the mutation profile as well as the response to chemotherapy and radiotherapy are distinct among HPV+ versus HPV-negative tumors. Furthermore, the presence of the virus induces activation of an immune response, in particular the recruitment of specific antiviral T lymphocytes to tumor sites. These T cells when activated produce soluble factors including cytokines and chemokines capable of modifying the local immune tumor microenvironment and impact on tumor response to the treatment. In this comprehensive review we investigated current knowledge on how the presence of an HPV can modify the inflammatory response systemically and within the tumor microenvironment's immunological responses, thereby impacting on disease prognosis and survival. We highlighted the research gaps and emerging approaches necessary to discover novel immunotherapeutic targets for HPV-associated HNSCC.

Effects of hybrid inorganic-organic nanofibers on the properties of enamel resin infiltrants - An in vitro study.

This in vitro study aimed to evaluate the overall mechanical properties of resin infiltrants doped with bioactive nanofibers and their ability in inhibiting enamel demineralization or achieving remineralization of the adjacent enamel to white spots. A commercial resin infiltrant (ICON, DMG) was doped with hybrid inorganic-organic nanofibers and analyzed for degree of conversion (DC, n = 3) and surface hardness (SH, n = 6). Subsequently, enamel specimens (6 × 4 × 2 mm3) were prepared and submitted to a demineralizing/remineralizing process to produce a subsurface caries-like lesion. The specimens were treated with one of the following materials: ICON infiltrant, DMG (control); ICON + nanofibers of poly-lactic acid (PLA)-filled with silica (PLA-SiO2); ICON + nanofibers of (PLA)-filled with calcium incorporated into a silica network (SiO2-CaP). Then, the specimens were subjected to a pH-cycling demineralizing/remineralizing model for 7 days at 37 °C. The %ΔSH change (after treatment), %SH loss and %SH recovery (after pH-cycling regimen) were calculated after SH evaluation (n = 9/group). The Ca/P weight ratio before and after pH-cycling regimen was evaluated through SEM/EDX. The results of DC were analyzed through the T-test (p < 0.05). ANOVA followed by Tukey's test (p < 0.05) was performed for hardness and EDX. A significant SH increase was observed in the ICON/SiO2CaP group (p < 0.05). The ICON/PLA-SiO2 presented higher DC values than the control group (p = 0.043). All groups presented significant difference in %ΔSH (p < 0.05), although the specimens treated with ICON/SiO2CaP presented greater values. Regarding the %SHL and %SHR, the ICON/SiO2CaP and ICON/PLA-SiO2 were significantly different compared to the control group (p < 0.001). However, no difference was observed between the ICON/SiO2CaP and ICON/PLA-SiO2. The Ca/P ratio showed that the ICON/SiO2CaP and ICON/PLA-SiO2 after the pH-cycling regimen differed from sound enamel and modified infiltrants before pH-cycling. In conclusion, tailored hybrid nanofibers may be incorporated into enamel resin infiltrants without compromise the mechanical properties of such experimental materials. These latter can inhibit the demineralization of enamel and increase its hardness during pH-clycling challange.

In vitro antibacterial and anti-inflammatory effects of Anacardium occidentale L. extracts and their toxicity on PBMCs and zebrafish embryos.

This study evaluated the in vitro antimicrobial and immunomodulatory action of crude extracts from Anacardium occidentale L. (cashew tree) leaves and bark, and to determine their toxicity to peripheral-blood mononuclear cells (PBMCs) and to zebrafish embryos and larvae. Chemical analysis of extracts was performed by proton nuclear magnetic resonance (1H-NMR). The antibacterial activity was evaluated against selected bacteria strains by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). Cytotoxicity of the extracts was assessed using resazurin method, while the effect on production of ROS by PMN leukocytes was measured by luminol. Embryotoxicity to zebrafish was assessed using the fish embryo acute toxicity test (FET) and quantification of toxicity marker enzymes (AChE, LDH, and GST). 1H-NMR results showed anacardic acid as the main component of the extracts. All bacterial species tested were sensitive to the extracts, with MICs ranging from 312.5 to 10,000 µg/mL. Streptococcus mutans and Escherichia coli were the most susceptible species. The extracts promoted cell viability above 75% at concentrations from 1.25 to 80 µg/mL. Both extracts reduced zymosan-induced ROS (p < 0.05) at concentrations of 1, 8, and 80 µg/mL compared to the control. In vivo, there were embryotoxic effects in zebrafish embryos exposed to both extracts through the presence of lethal and sublethal endpoints. The samples also acted by inhibiting the activities of biomarker enzymes. The A. occidentale L. bark and leaf extracts showed antimicrobial potential and modulated ROS production in vitro, but these also showed embryotoxic effects to zebrafish.

Novel Therapeutic Options for Chagas Disease Based on Bioactive Compounds from Algae, Bacteria and Fungi Species.

Chagas Disease, also known as American trypanosomiasis, is a Neglected Tropical Disease that affects around seven million people, especially in Latin America. Noteworthy, there has been an increase in the numbers of case reports in non-endemic areas, such as North America, Europe, Japan, and Australia. The disease is a vector-borne disease caused by the pathogen Trypanosoma cruzi being transmitted by infected bugs. It is known that about forty percent of infected patients develop cardiac, digestive, or neurological alterations. There are only two drugs currently used for treatment, benznidazole and nifurtimox. However, both therapeutic regimens present several limitations, such as toxicity, mutagenicity and low efficiency during the chronic phase. Some reports in the literature point to the occurrence of parasite resistance. To overcome these limitations, the bioprospection of novel molecules as alternatives is one of the major goals to improve therapeutic success in this chronic disease. Bioprospecting active metabolites from natural resources might bring new hopes for disease control and parasite elimination. Here we summarize the most recent advances to identify and test Algae, Bacteria and Fungi-derived bioactive compounds with trypanocidal activity using experimental models, in vitro testing and in silico approaches.

Effects of digested flours from four different sweet potato (Ipomoea batatas L.) root varieties on the composition and metabolic activity of human colonic microbiota in vitro.

This study evaluated the effects of flours from four different sweet potato root (SPR) varieties, being two with white peel and two with purple peel, on the composition and metabolic activity of human colonic microbiota in vitro. The capability of these SPR flours (20 g/L) to cause alterations in relative abundance of different bacterial groups found as part of human colonic microbiota, as well as in lactic acid and short-chain fatty acid production was evaluated during 48 hr of an in vitro colonic fermentation. The SPR flours were submitted to a simulated gastrointestinal digestion prior to use in experiments. The four SPR flours increased the relative abundance of Lactobacillus/Enterococcus (range: 0.49-4.48%) and Bifidobacterium (range: 0.32-3.27%) and decreased the relative abundance of Bacteroides/Prevotella (range: 0.29-7.49%), Clostridium histolyticum (range: 0.15-2.08%), and Eubacterium rectale/Clostridium coccoides (range: 0.28-3.86%) during the 48 hr of colonic fermentation. The four SPRF flours had positive prebiotic indexes (> 0.38) after 24 and 48 hr of colonic fermentation, reinforcing the occurrence of selective stimulatory effects on colonic microbiota. An increased metabolic activity of human colonic microbiota was caused by tested SPR flours, which was evidenced by decreased pH (range: 3.20-3.83) and increased lactic acid and short chain fatty acid production during the 48 hr of colonic fermentation. The four examined SPR flours were capable of causing positive alterations in composition and driving the metabolic activity of human colonic microbiota during in vitro colonic fermentation, which should be linked to their prebiotic properties. PRACTICAL APPLICATION: The four examined sweet potato root flours (SPRF) caused beneficial alterations in composition besides of driving the metabolic activity of human colonic microbiota in vitro. These results characterize the examined SPRF as candidates for use as prebiotic ingredients by food industry for formulation of value-added functional foods or dietary supplements.

Chitosan/PCL nanoparticles can improve anti-neoplastic activity of 5-fluorouracil in head and neck cancer through autophagy activation.

Head and neck squamous cell carcinoma (HNSCC), a prevalent cancer worldwide, has a high incidence of loco-regional dissemination, frequent recurrence, and lower 5-year survival rates. Current gold standard treatments for advanced HNSCC rely primarily on radiotherapy and chemotherapy but with limited efficacy and significant side effects. In this study, we characterized a novel 5-fluorouracil (5-FU) carrier composed of chitosan solution (CS) and polycaprolactone (PCL) microparticles (MPs) in HNSCC preclinical models. The designed MPs were evaluated for their size, morphology, drug entrapment efficiency (EE%) and in vitro drug release profile. The anti-cancer activity of 5-FU-loaded particles was assessed in HNSCC human cell lines (CAL27 and HSC3) and in a preclinical mouse model (AT84) utilizing cell proliferation and survival, cell motility, and autophagy endpoints. The results demonstrated a 38.57 % in 5-FU entrapment efficiency associated with reduced 5-FU in vitro release up to 96 h post-exposure. Furthermore, CS-decorated PCL MPs were able to promote a significant inhibition of cancer cell proliferation based on the metabolic and colony formation assays, in comparison to controls. In contrast, CS-decorated PCL MPs did not influence the pharmacological efficacy of 5-FU to inhibit in vitro cancer cell migration. Last, cell protein analysis revealed a significant increase of autophagy and cell death evaluated by LC3-II expression and PARP1 cleavage, respectively. In summary, these results support the potential utility of CS-decorated PCL MPs as an effective 5-FU-delivery carrier to improve HNSCC therapeutic management.

Efficacy of essential oil of cinnamon for the treatment of oral candidiasis: A randomized trial.

AIM: It was analyzed the efficacy of mouthwash and spray containing essential oil (EO) of Cinnamomum zeylanicum Blume for the treatment of oral candidiasis. METHODS AND RESULTS: A randomized, controlled, and blinded clinical trial was conducted with 36 individuals (probabilistic sample) with oral candidiasis who were divided into two treatment groups: C. zeylanicum (0.5 mg/mL), n = 18; nystatin (100,000IU/mL), n = 18. The efficacy of the products was evaluated by two parameters: (a) clinical evolution recorded by calibrated examiners (Kappa = 0.822) according to Newton's classification and (b) reduction of colony-forming units/mL. Mycological and clinical parameters were analyzed before and at 15 days after treatment. Clinical examination of the mucosa showed that C. zeylanicum (p < 0.0339) and nystatin (p < .0139) had efficacy, resulting in a reduction of signs and symptoms (Mann-Whitney test). Mycological analysis showed that C. zeylanicum caused a reduction of 61% and 33% of Candida spp., isolates oral mucosa and dentures, respectively. Candida tropicalis strains were eliminated after C. zeylanicum, in both sites. The participants reported a pleasant taste and few product-related complaints. CONCLUSION: C. zeylanicum EO and nystatin exhibited clinical efficacy, according to the Newton classification, and reducing in Candida spp. The clinical trial has been registered (Registration number: NBR-33s6 × 5, ensaiosclinicos.gov.br).

Effectiveness of Core-Shell Nanofibers Incorporating Amphotericin B by Solution Blow Spinning Against Leishmania and Candida Species.

The aim of this study was to develop polymeric nanofibers for controlled administration of Amphotericin B (AmpB), using the solution centrifugation technique, characterizing its microstructural and physical properties, release rate, and activity against Leishmania and Candida species. The core-shell nanofibers incorporated with AmpB were synthesized by Solution Blow Spinning (SBS) and characterized by scanning electron microscopy (SEM), differential scanning calorimetry, X-Ray diffraction, and drug release assay. In vitro leishmanicidal and antifungal activity were also evaluated. Fibrous membranes with uniform morphology and smooth surfaces were produced. The intensity of the diffraction peaks becomes slightly more pronounced, assuming the increased crystallization in PLA/PEG at high AmpB loadings. Drug release occurred and the solutions with nanofibers to encourage greater incorporation of AmpB showed a higher concentration. In the results of the experiment with promastigotes, the wells treated with nanofibers containing concentrations of AmpB at 0.25, 0.5, and 1%, did not have any viable cells, similar to the positive control. Various concentrations of AmpB improved the inhibition of fungal growth. The delivery system based on PLA/PEG nanofibers was properly developed for AmpB, presenting a controlled release and a successful encapsulation, as well as antifungal and antileishmanial activity.

SARS-CoV-2 and Saliva: an update

Covid-19 is a respiratory disease caused by the SARS-CoV-2 virus. The high rate of contagion and the spread of the virus in the population make the early detection of the pathogen the means for the adequate targeting of infection control measures. WHO directs sample collection on upper respiratory specimens, including nasopharyngeal and oropharyngeal swab or wash in ambulatory patients, as well as lower respiratory specimens: sputum and/or endotracheal aspirate or bronchoalveolar lavage, in addition to citing blood and feces. Among the various sample collection methods, saliva has been investigated and reported as a potential source for diagnosis. Thus, we propose to evaluate the current scenario, based on recent publications on the perspective of detecting SARS-CoV-2 in saliva as a diagnostic method for Covid-19.

Effects of Meglumine Antimoniate Treatment on Cytokine Production in a Patient with Mucosal Leishmaniasis and Chagas Diseases Co-Infection.

The influence of antimoniate treatment on specific anti-protozoan T-cell responses was evaluated in a 48-year-old male patient diagnosed with mucosal leishmaniasis and Chagas disease infection. Before and after treatment, PBMC (peripheral blood mononuclear cells) were cultured in the absence or presence of Leishmania braziliensis or Trypanosoma cruzi live parasites, their soluble antigens, or PHA (phytohaemagglutinin). Cytokines were measured and Treg (T regulatory) cell percentages were quantified. Before treatment, PBMC were able to produce higher amounts of TNF-α, IL-6 (Interleukin-6), and IL-10 (Interleukin-10) but lower amounts of IL-12 (Interleukin-12) in response to culture stimulation. However, after treatment, there was a down-modulation of TNF-α, IL-6, and IL-10 cytokines but an up-modulation in IL-12 production. PBMC had the ability to produce TNF-α only against live parasites or PHA. There was an overall decrease of circulating Treg cells after treatment. In mixed Leishmaniasis and Chagas disease infection, treatment with antimoniate could modulate immune responses toward a more protective profile to both diseases.

In Silico Identification of New Targets for Diagnosis, Vaccine, and Drug Candidates against Trypanosoma cruzi.

Chagas disease is a neglected tropical disease caused by the parasite Trypanosoma cruzi. Despite the efforts and distinct methodologies, the search of antigens for diagnosis, vaccine, and drug targets for the disease is still needed. The present study is aimed at identifying possible antigens that could be used for diagnosis, vaccine, and drugs targets against T. cruzi using reverse vaccinology and molecular docking. The genomes of 28 T. cruzi strains available in GenBank (NCBI) were used to obtain the genomic core. Then, subtractive genomics was carried out to identify nonhomologous genes to the host in the core. A total of 2630 conserved proteins in 28 strains of T. cruzi were predicted using OrthoFinder and Diamond software, in which 515 showed no homology to the human host. These proteins were evaluated for their subcellular localization, from which 214 are cytoplasmic and 117 are secreted or present in the plasma membrane. To identify the antigens for diagnosis and vaccine targets, we used the VaxiJen software, and 14 nonhomologous proteins were selected showing high binding efficiency with MHC I and MHC II with potential for in vitro and in vivo tests. When these 14 nonhomologous molecules were compared against other trypanosomatids, it was found that the retrotransposon hot spot (RHS) protein is specific only for T. cruzi parasite suggesting that it could be used for Chagas diagnosis. Such 14 proteins were analyzed using the IEDB software to predict their epitopes in both B and T lymphocytes. Furthermore, molecular docking analysis was performed using the software MHOLline. As a result, we identified 6 possible T. cruzi drug targets that could interact with 4 compounds already known as antiparasitic activities. These 14 protein targets, along with 6 potential drug candidates, can be further validated in future studies, in vivo, regarding Chagas disease.

SARS-CoV-2 and Saliva as a Diagnostic Tool: A Real Possibility

Abstract Covid-19 is a respiratory disease caused by the SARS-CoV-2 virus. The high rate of contagion and the spread of the virus in the population make the early detection of the pathogen the means for the adequate targeting of infection control measures. WHO directs sample collection on upper respiratory specimens, including nasopharyngeal and oropharyngeal swab or wash in ambulatory patients, as well as lower respiratory specimens: sputum and/or endotracheal aspirate or bronchoalveolar lavage, in addition to citing blood and feces. Among the various sample collection methods, saliva has been investigated and reported as a potential source for diagnosis. Thus, we propose to evaluate the current scenario, based on recent publications on the perspective of detecting SARS-CoV-2 in saliva as a diagnostic method for Covid-19. The detection of SARS-CoV-2 through saliva seems to be very promising, although obstacles such as the technique and the location of the collection and the sample size of the research carried out so far may present a limitation for its use. The current scenario presents saliva as a reliable method for the detection of SARS-CoV-2, due to the ease of obtaining the samples, the possibility of self-collection, low cost because there is no need to use specific equipment, in addition to reducing the risk of transmission for health professionals.

Current Applications of Biopolymer-based Scaffolds and Nanofibers as Drug Delivery Systems.

BACKGROUND: The high surface-to-volume ratio of polymeric nanofibers makes them an effective vehicle for the release of bioactive molecules and compounds such as growth factors, drugs, herbal extracts and gene sequences. Synthetic polymers are commonly used as sensors, reinforcements and energy storage, whereas natural polymers are more prone to mimicking an extracellular matrix. Natural polymers are a renewable resource and classified as an environmentally friendly material, which might be used in different techniques to produce nanofibers for biomedical applications such as tissue engineering, implantable medical devices, antimicrobial barriers and wound dressings, among others. This review sheds some light on the advantages of natural over synthetic polymeric materials for nanofiber production. Also, the most important techniques employed to produce natural nanofibers are presented. Moreover, some pieces of evidence regarding toxicology and cell-interactions using natural nanofibers are discussed. Clearly, the potential extrapolation of such laboratory results into human health application should be addressed cautiously.

Influence of stressing conditions caused by organic acids and salts on tolerance of Listeria monocytogenes to Origanum vulgare L. and Rosmarinus officinalis L. essential oils and damage in bacterial physiological functions.

This study evaluated whether the pre-exposure (24, 48 and 72 h) to sublethal conditions caused by acetic acid (AA), lactic acid (LA), sodium chloride (NaCl) or potassium chloride (KCl) could induce increased cross-tolerance to the essential oils from Origanum vulgare L. (OVEO) and Rosmarinus officinalis L. (ROEO) in different Listeria monocytogenes strains. Damage to membrane integrity, membrane potential, enzymatic activity and efflux activity in L. monocytogenes cells pre-exposed (24 h) to AA or NaCl and further treated with OVEO or ROEO (8 and 24 h) were investigated using flow cytometry (FC). Results of minimum inhibitory concentration (MIC) modulation test showed that pre-exposure to sublethal conditions caused by organic acids or salts increased cross-tolerance only to ROEO, since MIC of ROEO increased up to 4.8-fold against pre-exposed cells. Otherwise, MIC of OVEO against these pre-exposed cells was up to ten-fold lower than that observed against not pre-exposed cells, indicating no increase in cross-tolerance. Bacterial survival assays showed that ROEO only decreased the counts over time of cells not pre-exposed to organic acids or salts, while OVEO decreased similarly or more the counts of pre-exposed cells compared to not pre-exposed cells. Results of FC analysis showed that all measured functions in L. monocytogenes cells pre-exposed to AA or NaCl and treated with OVEO or ROEO were affected, although with different intensities. These data indicate that exposure to sublethal conditions imposed by organic acids or salts could result in a phenotype of increased cross-tolerance to ROEO but not to OVEO in L. monocytogenes.

Cytokine Regulation from Human Peripheral Blood Leukocytes Cultured In Vitro with Silver Doped Bioactive Glasses Microparticles.

Bioactive glasses (BG) applications include tissue engineering for bone regeneration, coating for implants, and scaffolds for wound healing. BG can be conjugated to ions like silver, which might add some antimicrobial properties to this biomaterial. The immunomodulatory activity of ion-doped bioactive glasses particles was not investigated before. The aim of this work was to evaluate the cytotoxic and immunomodulatory effect of BG and silver-doped bioactive glass (BGAg) in human peripheral blood cells. BG and BGAg samples belonging to the system 58SiO2 •(36-x)CaO·6P2O5 ·xAg2O, where x = 0 and 1 mol%, respectively, were synthesized via sol-gel method and characterized. Cytotoxicity, modulation of cytokine production (TNF-α, IL-1ß, IL-6, IL-4, and IL-10), and oxidative stress response were investigated in human polymorphonuclear cells (PMNs) and peripheral blood mononuclear cells (PBMCs) cultures. Cell viability in the presence of BG or BGAg was concentration-dependent. In addition, BGAg presented higher PBMCs toxicity (LC50 = 0.005%) when compared to BG (LC50 = 0.106%). Interestingly, interleukin4 was produced by PBMCs in response to BG and BGAg in absence of phytohemagglutinin (PHA) and did not modulate PHA-induced cytokine levels. Subtoxic concentrations (0.031% for BG and 0.0008% for BGAg) did not change other cytokines in PBMCs nor reactive oxygen species (ROS) production by PMN. However, BG and BGAg particles decreased zymosan-induced ROS levels in PMN. Although ion incorporation increased BG cytotoxicity, the bioactive glass particles demonstrated a in vitro anti-inflammatory potencial. Future studies are needed to clarify the scavenger potential of the BG/BGAg particles/scaffolds as well as elucidate the effect of the anti-inflammatory potential in modulating tissue growth in vivo.