Chemical Composition and Biological Activity of Essential Oil and Extract from the Seeds of Tropaeolum majus L. var. altum.

Research background: Plant Tropaeolum majus L. (garden nasturtium) belongs to the family Tropaeolaceae and contains benzyl glucosinolate. The breakdown product of benzyl glucosinolate, benzyl isothiocyanate (BITC), exhibits various biological activities such as antiproliferative, antibacterial and antiinflammatory. In order to optimize the content of biologically active volatile compounds in plant extract and essential oil, the use of appropriate extraction technique has a crucial role. Experimental approach: The current study investigates the effect of two modern extraction methods, microwave-assisted distillation (MAD) and microwave hydrodiffusion and gravity (MHG), on the chemical composition of volatile components present in the essential oil and extract of garden nasturtium (T. majus L. var. altum) seeds. Investigation of the biological activity of samples (essential oil, extract and pure compounds) was focused on the antiproliferative effect against different cancer cell lines: cervical cancer cell line (HeLa), human colon cancer cell line (HCT116) and human osteosarcoma cell line (U2OS), and the antibacterial activity which was evaluated against the growth and adhesion of Staphylococcus aureus and Escherichia coli to polystyrene surface. Results and conclusions: Essential oil and extract of garden nasturtium (T. majus) seeds were isolated by two extraction techniques: MAD and MHG. BITC and benzyl cyanide (BCN) present in the extract were identified by gas chromatography-mass spectrometry. Essential oil of T. majus showed higher antiproliferative activity (IC50<5 µg/mL) than T. majus extract (IC50<27 µg/mL) against three cancer cell lines: HeLa, HCT116 and U2OS. BITC showed much higher inhibitory effect on all tested cells than BCN. The essential oil and extract of T. majus showed strong antimicrobial activity against S. aureus and E. coli. Novelty and scientific contribution: This work represents the first comparative report on the antiproliferative activity of the essential oil and extract of T. majus seeds, BITC and BCN against HeLa, HCT116 and U2OS cells as well as their antimicrobial activity against S. aureus and E. coli. This study demonstrates that the essential oil of T. majus seeds exhibits stronger antiproliferative and antimicrobial activity than the plant extract.

The food industry by-products in bread making: single and combined effect of carob pod flour, sugar beet fibers and molasses on dough rheology, quality and food safety.

Obtaining high-quality value-added bread with extended shelf-life by utilizing food industry by-products that would have minimal negative effect on gluten structure while avoiding the usage of synthetic preservatives, was the challenge of this study. For this purpose the influence of the combination of carob pod flour (C, 0-15%), sugar beet fibers (F, 0-10%) and sugar beet molasses (M, 0-6%) on dough rheology and bread quality was investigated. Selected materials were of good microbiological quality, while carob flour and sugar beet fibers were rich in dietary fibers (43.6% and 67.0%, respectively). The presence of high share of dietary fibers (combination of C and F) increased dough resistance to extension up to 2.5 times, while dough extensibility was reduced by 50%. The addition of molasses had less pronounced single effect on dough properties however its impact in combination with fiber-rich materials outweighed the individual effect (an increase of dough resistance at about 55%). Molasses alone and in combination with other ingredients had positive effect on bread quality. Sample M6F5 attained crumb quality score (6.0 of maximum 7.0) higher than in control sample (5.6). High share of C and F reduced loaf volume and crumb quality of bread up to 56% and 50%, respectively and increased hardness 7.5 times. However, carob flour (7.5%) increased polyphenols content and antioxidant capacity 3 and 4 times, respectively. Moreover, carob flour and molasses and their combination showed inhibitory effect on mold mycelia growth and spores formation. Regarding all of the above, C7.5M3F5 was chosen as optimal sample.

Antibiofilm Potential of Lavandula Preparations against Campylobacter jejuni.

New approaches for the control of Campylobacter jejuni biofilms in the food industry are being studied intensively. Natural products are promising alternative antimicrobial substances to control biofilm production, with particular emphasis on plant extracts. Dried flowers of Lavandula angustifolia were used to produce essential oil (LEO), an ethanol extract (LEF), and an ethanol extract of Lavandula postdistillation waste material (LEW). The chemical compositions determined for these Lavandula preparations included seven major compounds that were selected for further testing. These were tested against C. jejuni for biofilm degradation and removal. Next-generation sequencing was used to study the molecular mechanisms underlying LEO actions against C. jejuni adhesion and motility. Analysis of LEO revealed 1,8-cineol, linalool, and linalyl acetate as the main components. For LEF and LEW, the main components were phenolic acid glycosides, with flavonoids rarely present. The MICs of the Lavandula preparations and pure compounds against C. jejuni ranged from 0.2 mg/ml to 1 mg/ml. LEO showed the strongest biofilm degradation. The reduction of C. jejuni adhesion was ≥1 log10 CFU/ml, which satisfies European Food Safety Authority recommendations. Lavandula preparations reduced C. jejuni motility by almost 50%, which consequently can impact biofilm formation. These data are in line with the transcriptome analysis of C. jejuni, which indicated that LEO downregulated genes important for biofilm formation. LEW also showed good antibacterial and antibiofilm effects, particularly against adhesion and motility mechanisms. This defines an innovative approach using alternative strategies and novel targets to combat bacterial biofilm formation and, hence, the potential to develop new effective agents with biofilm-degrading activities. IMPORTANCE The Lavandula preparations used in this study are found to be effective against C. jejuni, a common foodborne pathogen. They show antibiofilm properties at subinhibitory concentrations in terms of promoting biofilm degradation and inhibiting cell adhesion and motility, which are involved in the initial steps of biofilm formation. These results are confirmed by transcriptome analysis, which highlights the effect of Lavandula essential oil on C. jejuni biofilm properties. We show that the waste material from the hydrodistillation of Lavandula has particular antibiofilm effects, suggesting that it has potential for reuse for industrial purposes. This study highlights the need for efforts directed toward such innovative approaches and alternative strategies against biofilm formation and maintenance by developing new naturally derived agents with antibiofilm activities.

Phenolic Profile, Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques.

Nettle is a widely known plant whose high biological activity and beneficial medicinal effects are attributed to various bioactive compounds, among which polyphenols play an important role. In order to isolate polyphenols and preserve their properties, advanced extraction techniques have been applied to overcome the drawbacks of conventional ones. Therefore, microwave-assisted extraction (MAE) has been optimized for the isolation of nettle leaves polyphenols and it was compared to pressurized liquid extraction (PLE) and conventional heat-reflux extraction (CE). The obtained extracts were analyzed for their individual phenolic profile by UPLC MS2 and for their antioxidant capacity by ORAC assay. MAE proved to be the more specific technique for the isolation of individual phenolic compounds, while PLE produced extracts with higher amount of total phenols and higher antioxidant capacity. Both techniques were more effective compared to CE. PLE nettle extract showed antimicrobial activity against bacteria, especially against Gram-negative Pseudomonas fragi ATCC 4973 and Campylobacter jejuni NCTC 11168 strains. This suggests that PLE is suitable for obtaining a nettle extract with antioxidant and antimicrobial potential, which as such has great potential for use as a value-added ingredient in the food and pharmaceutical industry.

Development of Biodegradable Whey-Based Laminate Functionalised by Chitosan-Natural Extract Formulations.

In this research, antimicrobial polysaccharide chitosan and natural extracts were used as surface coating of a plastic laminate with an integrated whey layer on the inside. The aim was to establish the biodegradable and active concept of packaging laminates. For this purpose, chitosan nanoparticles (CSNPs) with embedded rosemary or cinnamon extracts were synthesised and characterised. Additionally, a whey-based laminate was functionalised: i) chitosan macromolecular solution was applied as first layer and ii) cinnamon or rosemary extracts encapsulated in CSNPs were applied as upper layer (layer wise deposition). Such functionalised whey-based laminate was physicochemically characterized in terms of elemental surface composition, wettability, morphology and oxygen permeability. The antimicrobial activity was tested against Staphylococcus aureus, Escherichia coli, Aspergillus flavus and Penicillium verrucosum. The antioxidant properties were determined using the ABTS assay. It could be shown that after functionalization of the films with the above-mentioned strategy, the wettability was improved. Furthermore, such whey-based laminates still show excellent barrier properties, good antimicrobial activity and a remarkable antioxidative activity. In addition to the improved biodegradability, this type of lamination could also have a positive effect on the shelf-life of products packaged in such structured films.

Bioactive Characterization of Packaging Foils Coated by Chitosan and Polyphenol Colloidal Formulations.

Polypropylene (PP) and polyethylene (PE) foils, previously activated by ultraviolet (UV)/ozone, were functionalized using chitosan-extract nanoparticle dispersions. A solution of macromolecular chitosan was applied onto foils as a first layer, followed by the deposition of various extracts encapsulated into chitosan nanoparticles, which were attached as an upper layer. Functionalized foils were analyzed from a bioactive point of view, i.e., regarding antimicrobial and antioxidant activity. Desorption kinetics were also studied. Moreover, barrier properties were examined, as the most important parameter influencing antimicrobial and antioxidant activity. Finally, all these properties were correlated with different surface parameters, determined previously, in order to understand if there is any direct correlation between surface elemental composition, surface charge, contact angle, or morphology and a specific bioactive property. It was shown that great bioactive properties were introduced due to the additive effect of antimicrobial chitosan and antioxidative plant extracts. Moreover, oxygen permeability decreased significantly, and the migration of polyphenols and chitosan from the foil surface was below the OML (overall migration limit), which is very important for food industry applications. Furthermore, surface properties of foils influence to some extent the desired bioactivity.

Combination of rosemary extract and buffered vinegar inhibits Pseudomonas and Shewanella growth in common carp (Cyprinus carpio).

BACKGROUND: Aquaculture is the fastest growing food-production sector, and common carp (Cyprinus carpio) is one of the most cultivated fish species in the world. Due to its intrinsic characteristics, fish meat is highly susceptible to microbiological spoilage. Pseudomonas and Shewanella are the primary and secondary occurring microbiota during storage of fish meat, with significant contribution to spoilage with the formation of hydrolytic enzymes (lipases and proteases). RESULTS: With in vitro testing, we show that rosemary extract (Inolens4), buffered vinegar and their combination (SyneROX) exhibit antimicrobial effects against P. fragi, P. psychrophila, S. putrefaciens and S. xiaemensis at concentrations of 3.13 and 1.56 mg mL-1 . The combination was the most effective in inhibiting growth of selected bacteria in food model, and production of lipases and proteases during 9 days at 5 °C. In situ testing of antimicrobial dip treatment of carp meat determined that aerobic mesophilic, total psychrotrophic, Pseudomonas and hydrogen sulfide producer counts were reduced in all treatments, with the most prominent influence being shown by the combination and buffered vinegar. CONCLUSIONS: Our study highlights the importance of a multilevel assessment of the antimicrobial potential of biopreservatives under conditions comparable to those of the selected food. Investigation with bacteria and food model provided coherent and consistent data for the evaluation of the antimicrobial potential for carp meat. Combination of buffered vinegar (as active antimicrobial) and rosemary extract, with well-known and researched antioxidant properties but low in situ antimicrobial activity, represents a good potential for combined effect in preservation of fish meat. © 2020 Society of Chemical Industry.

Spoilage Pseudomonas biofilm with Escherichia coli protection in fish meat at 5 °C.

BACKGROUND: Pseudomonas are part of the indigenous microbiota of different foods, where they gradually cause spoilage. In fish meat, Pseudomonas fragi and Pseudomonas psychrophila have been identified as important spoilers. The initial aim of this study was to investigate the physiological characteristics, adhesion, and biofilm of P. fragi and P. psychrophila under temperatures related to the fish-processing industry. The further aim was to define the problem of increased growth of pathogenic bacteria in the presence of spoilage bacteria in vitro and in fish meat. RESULTS: Temperature dependence on physiological characteristics, adhesion, and biofilm was observed. Hydrophobicity and autoaggregation were most prominent at 15 °C, and at this temperature floating biofilm was also formed. The adhesion of these Pseudomonas was up to 2 log CFU cm-1 more pronounced on stainless steel than polystyrene, with up to five times greater biofilm biomass production at 5 °C on polystyrene. This paralleled at least a 0.5 log CFU g-1 increase in the pathogenic bacterium Escherichia coli in fish meat. CONCLUSION: Pseudomonas fragi and P. psychrophila adhesion and biofilm depend on the temperature, and are stimulated by temperatures that can occur during the processing and storage of fish meat. Strong Pseudomonas biofilm formation under refrigeration conditions is protective for E. coli, potentially by providing more favorable conditions by ensuring a higher concentration of nutrients. Interactions between spoilage Pseudomonas and pathogenic bacteria can occur through different mechanisms, and an understanding of these is of particular importance to ensure the overall quality and safety of fish meat and other proteinaceous foods. © 2019 Society of Chemical Industry.

Antiadhesion activity of juniper (Juniperus communis L.) preparations against Campylobacter jejuni evaluated with PCR-based methods.

The food-borne pathogen Campylobacter jejuni can cause bacterial gastrointestinal infections. Biofilm formation amplifies the risk of human infection by improving survival and persistence of C. jejuni in food processing environments and its transmission through the food chain. We aimed to control C. jejuni using an alternative strategy of low doses of Juniperus communis fruit preparations to target bacterial adhesion properties in the first step of biofilm formation. First, we defined the anti-Campylobacter activity of a juniper fruit crude extract and its fractionated biflavonoids, flavone glycosides, and purified amentoflavone, of juniper fruit essential oil and of juniper fruit postdistillation waste material extract. For accurate quantification of adherent C. jejuni, we optimised digital Polymerase Chain Reaction (PCR) and quantitative real-time PCR for construction of standard curves and quantification. We show for the first time that juniper fruit formulations can effectively inhibit adhesion of C. jejuni to polystyrene. Furthermore, ≥94% of the antiadhesion activity of juniper fruit crude extract and juniper fruit essential oil remained under food-related conditions: modified culture medium with glucose, or a stainless steel surface, or mixed co-cultures of C. jejuni and Listeria monocytogenes. This study indicates that addition of juniper fruit formulations can control growth and adhesion of C. jejuni and thus limit food chain transmission of campylobacters.

Bleeding of Common Carp (Cyprinus carpio) Improves Sensory Quality of Fillets and Slows Oxidative and Microbiological Changes During Refrigerated Aerobic Storage.

Common carp (Cyprinus carpio) aquaculture is one of the most important and rapidly growing productions around the world. However, for consumers, carp is often not acceptable due to its distinctive colour and odour. In this study, we investigated the effects of bleeding of common carp on fillet quality. The obtained results show that carp bleeding by cutting the gill arches is an effective way of reducing the total haem content, which here decreased from (9.6±1.6) in unbled carp to (2.34±0.8) µmol/kg of haemoglobin in bled carp. Furthermore, fillets from bled carp showed reduced formation of primary and secondary lipid oxidation products and growth of microorganisms during 12 days of refrigerated aerobic storage. On the last day of storage, the amount of lipid hydroperoxides decreased from (88.9±4.2) in unbled to (62.1±2.9) µmol/kg of cumene hydroperoxide in bled carp, TBARS decreased from (4.2±0.5) in unbled to (2.6±0.4) µmol/kg of malondialdehyde in bled carp, mesophilic and psychrotrophic bacteria count decreased from (6.4±0.1) and (6.2±0.3) log CFU/g in unbled to (4.0±0.2) and (4.2±0.2) log CFU/g in bled carp, respectively. These raw bled fillets showed increased lightness L*, and reduced redness a* and yellowness b* compared to unbled fillets. Sensory analysis showed improved colour, odour and overall acceptability of bled raw fillets. Overall, bleeding improves the quality of carp fillets. Thus, inclusion of bleeding into processing of carp fillets has the potential to improve their acceptance by consumers and prolong their shelf-life.

Aqueous Extracts of Wild Mushrooms Show Antimicrobial and Antiadhesion Activities against Bacteria and Fungi.

Mushrooms represent promising sources of novel bioactive compounds and can be applied as innovative strategies to control microbial contamination and infection via the food chain. We characterized aqueous extracts from 21 wild basidiomycete mushrooms and the cultivated oyster mushroom, Pleurotus ostreatus, as putative sources of antimicrobial and antiadhesive compounds. Broth microdilutions and adhesion to a polystyrene surface were evaluated on Gram-positive and Gram-negative bacteria and on fungi. The aqueous extracts tested showed antimicrobial and antiadhesive activities against these microorganisms. Biochemical analyses of the P. ostreatus extract indicated the involvement of several compounds with different molecular masses. Copyright © 2017 John Wiley & Sons, Ltd.

Attenuation of Adhesion, Biofilm Formation and Quorum Sensing of Campylobacter jejuni by Euodia ruticarpa.

Thermophilic campylobacters are a major cause of bacterial food-borne diarrhoeal disease. Adherence and biofilm formation are key elements of Campylobacter jejuni persistence in unfavourable environmental conditions. The phytochemical analysis of Euodia ruticarpa fruit ethanol solution extract (EREE) indicated that the major compounds were evodiamine (1), rutaecarpine (2) and evocarpine (9). E. ruticarpa fruit ethanol solution extract, compounds 1 and 2 as well as a mixture of quinolinone alkaloids with 41.7% of 9 were tested for antibacterial, antibiofilm and antiquorum sensing activities against C. jejuni. Minimal inhibitory concentrations varied from 64 to 1024 µg/mL. A mutant strain that lacks the functional gene coding for the CmeB efflux pump protein was the most susceptible. Interestingly, in addition to the wild-type (NCTC 11168) and cmeB mutant, also a mutant that lacks autoinducer-2 production (luxS) was able to adhere (1 h) and to produce a biofilm (24, 48 and 72 h). The subinhibitory concentrations of all preparations at least partly inhibited C. jejuni adhesion and biofilm formation with the most visible effect of the quinolinone alkaloid fraction. Using a Vibrio harveyi luminescence assay, the inhibition of autoinducer-2 production was observed in the wild-type and cmeB mutant after 48 h with the most visible effect of EREE and its fraction Q. Copyright © 2016 John Wiley & Sons, Ltd.

Anti-adhesion activity of thyme (Thymus vulgaris L.) extract, thyme post-distillation waste, and olive (Olea europea L.) leaf extract against Campylobacter jejuni on polystyrene and intestine epithelial cells.

BACKGROUND: In order to survive in food-processing environments and cause disease, Campylobacter jejuni requires specific survival mechanisms, such as biofilms, which contribute to its transmission through the food chain to the human host and present a critical form of resistance to a wide variety of antimicrobials. RESULTS: Phytochemical analysis of thyme ethanolic extract (TE), thyme post-hydrodistillation residue (TE-R), and olive leaf extract (OE) using high-performance liquid chromatography with photodiode array indicates that the major compounds in TE and TE-R are flavone glucuronides and rosmarinic acid derivatives, and in OE verbascoside, luteolin 7-O-glucoside and oleuroside. TE and TE-R reduced C. jejuni adhesion to abiotic surfaces by up to 30% at 0.2-12.5 µg mL(-1) , with TE-R showing a greater effect. OE from 3.125 to 200 µg mL(-1) reduced C. jejuni adhesion to polystyrene by 10-23%. On the other hand, C. jejuni adhesion to PSI cl1 cells was inhibited by almost 30% over a large concentration range of these extracts. CONCLUSION: Our findings suggest that TE, the agro-food waste material TE-R, and the by-product OE represent sources of bioactive phytochemicals that are effective at low concentrations and can be used as therapeutic agents to prevent bacterial adhesion. © 2015 Society of Chemical Industry.

Polyphenol, antioxidant and antimicrobial potential of six different white and red wine grape processing leftovers.

BACKGROUND: During winemaking, grape polyphenols are only partly extracted, and consequently unexploited. The main aim was to characterize the phenolic content of freeze-dried grape skin and seed (FDSS) extracts obtained from Slovenian and international grape varieties and to evaluate their antioxidant, antimicrobial and anti-adhesive activities. RESULTS: FDSS of six Vitis vinifera L. grapevine cultivars from Vipava Valley region (Slovenia) underwent extraction and sonification under different conditions. Flavonols were the predominant content of extracts from white 'Zelen' and 'Sauvignon Blanc' grape varieties, with strong antimicrobial activities against Gram-negative bacteria. 'Pinot Noir' FDSS extracted with 50% aqueous ethanol extraction produced a high phenolic content in the final extract, which was further associated with strong antioxidant and antimicrobial activities against all tested bacteria. Bacterial adhesion to stainless steel surfaces with minimal and maximal surface roughness was significantly inhibited (up to 60%) across a wide FDSS concentration range, with lower concentrations also effective with two types of stainless steel surfaces. CONCLUSION: FDSS extracts from winery by-products show interesting phenolic profiles that include flavonols, catechins, anthocyanins and hydroxycinnamic acids, with yields influenced by grapevine cultivar and extraction conditions. The antioxidant, antimicrobial and anti-adhesive activities of 50% aqueous ethanol 'Pinot Noir' FDSS extract reveals potential applications in food, pharmaceutical and cosmetic industries for these bioactive residues. © 2016 Society of Chemical Industry.

Exploring chitosan-plant extract bilayer coatings: Advancements in active food packaging via polypropylene modification.

UV-ozone activated polypropylene (PP) food films were subjected to a novel bilayer coating process involving primary or quaternary chitosan (CH/QCH) as the first layer and natural extracts from juniper needles (Juniperus oxycedrus; JUN) or blackberry leaves (Rubus fruticosus; BBL) as the second layer. This innovative approach aims to redefine active packaging (AP) development. Through a detailed analysis by surface characterization and bioactivity assessments (i.e., antioxidant and antimicrobial functionalities), we evaluated different coating combinations. Furthermore, we investigated the stability and barrier characteristics inherent in these coatings. The confirmed deposition, coupled with a comprehensive characterization of their composition and morphology, underscored the efficacy of the coatings. Our investigation included wettability assessment via contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and attenuated total reflectance Fourier-transform infrared spectroscopy (ATR-FTIR), which revealed substantial enhancements in surface concentrations of elements and functional groups of CH, QCH, JUN, and BBL. Scanning electron microscopy (SEM) unveiled the coatings' heterogeneity, while time-of-flight secondary ion mass spectrometry (ToF-SIMS) and CA profiling showed moderately compact bilayers on PP, providing active species on the hydrophilic surface, respectively. The coatings significantly reduced the oxygen permeability. Additionally, single-layer depositions of CH and QCH remained below the overall migration limit (OML). Remarkably, the coatings exhibited robust antioxidative properties due to plant extracts and exceptional antimicrobial activity against S. aureus, attributed to QCH. These findings underscore the pivotal role of film surface properties in governing bioactive characteristics and offer a promising pathway for enhancing food packaging functionality.

Overcoming antibiotic resistance: non-thermal plasma and antibiotics combination inhibits important pathogens.

Antibiotic resistance (ATBR) is increasing every year as the overuse of antibiotics (ATBs) and the lack of newly emerging antimicrobial agents lead to an efficient pathogen escape from ATBs action. This trend is alarming and the World Health Organization warned in 2021 that ATBR could become the leading cause of death worldwide by 2050. The development of novel ATBs is not fast enough considering the situation, and alternative strategies are therefore urgently required. One such alternative may be the use of non-thermal plasma (NTP), a well-established antimicrobial agent actively used in a growing number of medical fields. Despite its efficiency, NTP alone is not always sufficient to completely eliminate pathogens. However, NTP combined with ATBs is more potent and evidence has been emerging over the last few years proving this is a robust and highly effective strategy to fight resistant pathogens. This minireview summarizes experimental research addressing the potential of the NTP-ATBs combination, particularly for inhibiting planktonic and biofilm growth and treating infections in mouse models caused by methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa. The published studies highlight this combination as a promising solution to emerging ATBR, and further research is therefore highly desirable.

Perspectives on antimicrobial properties of Paulownia tomentosa Steud. fruit products in the control of Staphylococcus aureus infections.

ETHNOPHARMACOLOGICAL RELEVANCE: Paulownia tomentosa Steud. (P. tomentosa) is a medium-sized tree traditionally used in Chinese folk medicine for the treatment of infectious diseases. It is a rich source of prenylated phenolic compounds that have been extensively studied for their promising biological activities. AIM OF THE STUDY: Due to the increasing development of antibiotic resistance, our study investigated plant-derived natural products from the fruits of P. tomentosa that could control Staphylococcus aureus infections with novel targets/modes of action and reduce antimicrobial resistance. MATERIALS AND METHODS: The ethanolic extract was fractionated and detected by liquid chromatography. The antistaphylococcal effects of the plant formulations were studied in detail in vitro by various biological methods, including microdilution methods for minimum inhibitory concentration (MIC), the checkerboard titration technique for synergy assay, fluorescence measurements for membrane disruption experiments, autoinducer-2-mediated bioassay for quorum sensing inhibition, and counting of colony-forming units for relative adhesion. Morphology was examined by transmission electron microscopy. RESULTS: Total ethanolic extract and chloroform fraction showed MICs of 128 and 32 µg/mL, respectively. Diplacol, diplacone, and 3'-O-methyl-5'-hydroxydiplacone inhibited S. aureus growth in the range of 8-16 µg/mL. Synergistic potential was shown in combination with mupirocin and fusidic acid. The ethanolic extract and the chloroform fraction destroyed the cell membranes by 91.61% and 79.46%, respectively, while the pure compounds were less active. The ethanolic extract and the pure compounds reduced the number of adhered cells to 47.33-10.26% compared to the untreated control. All tested plant formulations, except diplacone, inhibited quorum sensing of S. aureus. Transmission electron microscopy showed deformation of S. aureus cells. CONCLUSIONS: The products from the fruit of P. tomentosa showed antimicrobial properties against S. aureus alone and in combination with antibiotics. By affecting intracellular targets, geranylated flavonoids proposed novel approaches in the control of staphylococcal infections.

Dietary Intake of Adolescents and Alignment with Recommendations for Healthy and Sustainable Diets: Results of the SI.Menu Study.

BACKGROUND: The SI.Menu study offers the latest data on the dietary intake of Slovenian adolescents aged 10 to 17. The purpose of this study is to comprehensively assess their dietary intake (energy and nutrients) and compare their food intakes with dietary recommendations for healthy and sustainable diets. METHODS: The cross-sectional epidemiological dietary study SI.Menu (March 2017-April 2018) was conducted on a representative sample of Slovenian adolescents aged 10 to 17 years (n = 468) (230 males and 238 females). Data on dietary intake were gathered through two non-consecutive 24 h recalls, in line with the European Food Safety Authority (EFSA) EU Menu methodology. The repeated 24 h Dietary Recall (HDR) and Food Propensity Questionnaire (FPQ) data were combined to determine the usual intakes of nutrients and food groups, using the Multiple Source Method (MSM) program. RESULTS: Adolescents' diets significantly deviate from dietary recommendations, lacking vegetables, milk and dairy products, nuts and seeds, legumes, and water, while containing excessive meat (especially red meat) and high-sugar foods. This results in insufficient intake of dietary fibre, and nutrients such as vitamin D, folate, and calcium. CONCLUSIONS: The dietary intake of Slovenian adolescents does not meet healthy and sustainable diet recommendations. This study provides an important insight into the dietary habits of Slovenian adolescents that could be useful for future public health strategies.

In vivo modulation of Campylobacter jejuni virulence in response to environmental stress.

Campylobacters have developed a number of mechanisms for responding to environmental conditions, although the different virulence properties of these cells following exposure to stress are still poorly understood. We analyzed in vitro stress responses and the consequent in vivo modulation of Campylobacter jejuni pathogenicity in BALB/c mice, as a result of the exposure of the C. jejuni to environmental stress (starvation, oxidative stress, heat shock). In vitro, the influence of starvation and oxidative stress was milder than that of heat shock, although the majority of the stress conditions influenced the survival of C. jejuni. During starvation, C. jejuni viability was maintained longer than its culturability. Additionally, starvation elicited transformation of stressed bacteria to coccoid forms. In contrast, bacteria exposed to oxygen remained culturable, but their viability decreased. Pre-starvation did not contribute to improved survival of C. jejuni cells during oxygen exposure. Changes in bacteria numbers and the levels of several cytokines (interleukins 6 and 10, tumor necrosis factor-α, interferon-γ) were followed in vivo, in liver homogenates from the mice intravenously infected with either control (untreated) or stressed C. jejuni. The systemic infection with the control or stressed C. jejuni occurred with different production dynamics of the cytokines investigated. Starvation was the most powerful stress factor, which significantly decreased infectious potential of C. jejuni during the first 3 days postinfection. The most pronounced differences in cytokine production were found in interferon-γ and interleukin-10 production, which indicates that these have roles in the immune response to C. jejuni infection. These in vivo studies of environmental impact on bacterial virulence reveal that microbial adaptation during stress challenge is crucial not just for pathogen survival out of the host, but also during host-pathogen interactions, and thus for the bacterial pathogenicity.