Antibacterial effect and mechanism of anthocyanin rich Chinese wild blueberry extract on various foodborne pathogens

Antilisterial activity of cinnamon essential oil, pomegranate extract, or strawberry tree extract against Listeria monocytogenes in slices of dry-cured ham and pork loin

Owing to concerns about the antimicrobial resistance of agents that can prevent the growth of Listeria monocytogenes in meat, researchers have investigated natural preservatives with antilisterial effects. However, in vivo application of essential oils and plant extracts usually results in reduced antimicrobial activity in meat products when compared to in vitro studies. This study aimed to evaluate the in vivo antimicrobial activity of cinnamon essential oil, pomegranate, and strawberry tree extracts in slices of dry-cured ham and pork loin against L. monocytogenes. Fragments of sterile dry-cured ham were inoculated with 100 μL cinnamon oil 0.5%, pomegranate, or strawberry crude extract. After 10 min, 100 μL of L. monocytogenes serotype 4b (104 colony-forming unit [CFU]/mL) was inoculated, and samples were incubated at 7 °C for 7 d to simulate the processing and storage temperature conditions of dry-cured meat products. L. monocytogenes was detected and quantified. Only strawberry extract presented significant differences (P < 0.05) from the control; thus, it was selected for the assay with 2% and 4% salt-treated pork loin. The strawberry tree extract significantly (P < 0.05) reduced the growth of L. monocytogenes in dry-cured ham. However, it could not reduce L. monocytogenes growth in pork loin, regardless of the salt concentration. This is the first report on the antimicrobial effect of strawberry tree leaf extract against L. monocytogenes in dry-cured ham.

Eco-Friendly and Smart Electrospun Food Packaging Films Based on Polyvinyl Alcohol and Sumac Extract: Physicochemical, Mechanical, Antibacterial, and Antioxidant Properties

With the increasing concern over environmental pollution caused by synthetic packaging, there is a growing demand for sustainable, biodegradable, and functional materials in the food industry. In this study, the antioxidant, antimicrobial, physicochemical, and mechanical properties of electrospun edible films based on sumac extract and polyvinyl alcohol were investigated. The films demonstrated a clear colorimetric response to pH changes, shifting from red in acidic to yellow in alkaline conditions, making them suitable for food packaging and freshness monitoring. The film containing 30% sumac extract (P-SE 30%) exhibited strong antimicrobial activity against Escherichia coli (17.01 mm) and Staphylococcus aureus (18.02 mm), along with acceptable antioxidant activity (46.32%). The film with 10% sumac extract showed the best mechanical strength (0.034 MPa). Moreover, moisture content (4.3%) and water vapor permeability (9.49 g mm/m2 Pa) were significantly reduced. Also, the physicochemical properties (SEM, FT-IR, X-ray, thickness, Opacity, and mechanical) of electrospun films were improved compared to the control sample. In general, this study demonstrates the potential of electrospun films reinforced with sumac extract as a smart food packaging solution for enhancing food safety.

Structural and functional properties of common natural organic cations

BACKGROUND

Natural products have emerged as a critical focus in modern scientific research due to their structural diversity and therapeutic potential. Among these are natural organic cations-a distinct class of nitrogen- and oxygen-containing compounds. Despite their pharmacological relevance, the literature lacks a systematic synthesis of structure-activity relationships for natural organic cations (NOC). This gap hinders the rational development of NOC-based therapies as sustainable alternatives to synthetic compounds.

METHODS

Literature was searched and collected using databases, including PubMed, Science Direct, and Web of Science. The search terms used included "natural organic cation", "alkaloid", "anthocyanin", "structure-activity relationship", "charge interaction", "π-cation interaction", "biological activity", "antimicrobial", "antioxidant", "anticancer", "neuroprotection", "anti-inflammatory", "berberine", "coptisine", "palmatine", "cyanidin", "delphinidin", "pelargonidin", "free radical scavenging", "gut microbiota metabolism", "NF-κB pathway", "G-quadruplex DNA", "isoquinoline alkaloid", "protoberberine", "benzophenanthridine", "planar conjugated system", "charge delocalization", "methylenedioxy group", and several combinations of these words.

RESULTS

The bioactivity of NOC is underestimated. This review uncovers the structure-activity relationships of NOC. Firstly, planar conjugated systems and substituents control target binding: N⁺ in alkaloids enhances DNA/protein affinity, while O⁺ in anthocyanins enables free radical scavenging and enzyme inhibition. Secondly, cationic species outperform neutral analogs in antimicrobial potency, antioxidant capacity, and target selectivity. NOC bind to biomolecules via π-cation/π-π stacking and electrostatic binding. Charge localization in conjugated systems enhances stability and bioactivity.

CONCLUSION

This review consolidates evidence that NOC represent promising candidates for replacing synthetic compounds in therapies for cancer, neurodegeneration, metabolic disorders, etc. Key findings highlight the superiority of cationic species in target engagement and bioactivity, driven by planar conjugated systems and substituent effects. However, clinical translation requires addressing gaps in bioavailability and long-term safety. Future research must prioritize structural optimization and mechanistic validation. By bridging these gaps, NOC could advance as sustainable, low-toxicity agents in precision medicine and functional nutrition.

Antimicrobial Potential of Polyphenols: Mechanisms of Action and Microbial Responses-A Narrative Review

Polyphenols (PPs) are recognized as bioactive compounds and antimicrobial agents, playing a critical role in enhancing food safety, preservation, and extending shelf life. The antimicrobial effectiveness of PPs has different molecular and biological reasons, predominantly linked to their hydroxyl groups and electron delocalization, which interact with microbial cell membranes, proteins, and organelles. These interactions may reduce the efficiency of metabolic pathways, cause destructive damage to the cell membrane, or they may harm the proteins and nucleic acids of the foodborne bacteria. Moreover, PPs exhibit a distinctive ability to form complexes with metal ions, further amplifying their antimicrobial activity. This narrative review explores the complex and multifaceted interactions between PPs and foodborne pathogens, underlying the correlation of their chemical structures and mechanisms of action. Such insights shed light on the potential of PPs as innovative natural preservatives within food systems, presenting an eco-friendly and sustainable alternative to synthetic additives.

Impact of Encapsulation Position in Pickering Emulsions on Color Stability and Intensity Turmeric Oleoresin

The emulsification of natural pigment is a widely utilized strategy to enhance its stability in the food industry. However, high turbidity in emulsions often causes color fading, limiting their application. Here, we developed a comprehensive Pickering emulsion (PE) system to improve the color intensity and stability of turmeric oleoresin (Tur) under various food processing conditions. Specifically, the effects of two encapsulation positions within the PE were compared: the inner oil phase (Tur-IPE) and the outer solid particle layer (Tur-OPE). Lysozyme and carboxymethyl cellulose nanoparticles (NPs) were used as natural solid particle surfactants, with their successful formation confirmed through physical property analysis and FTIR spectroscopy. The optimal oil fraction (φ) for suitable physical properties of PE was determined to be 0.2. Interestingly, Tur-OPE significantly exceeded Tur-conventional emulsions (Tur-CE) and Tur-IPE in terms of color vividness, exhibiting higher redness and lower lightness (p < 0.05). During thermal processing at 70 and 90 °C, all emulsions demonstrated significantly enhanced heat resistance, retaining 1.3 to 1.6 times more Tur, respectively, compared to unencapsulated Tur (free Tur) (p < 0.05). Furthermore, Tur's pH instability was significantly overcome by encapsulation in all emulsion systems (p < 0.05). During 4 weeks of storage period, Tur-OPE demonstrated the highest retention rates, with the half-life of Tur increasing in the following order: free Tur < Tur-CE < Tur-IPE < Tur-OPE. Thus, we highlighted the important role of encapsulation position in PEs in improving and maintaining the color stability and vividness of natural pigments under various food processing conditions.

Synergistic antibacterial effect of ginsenoside Rh2 and calcium hydroxide on Enterococcus faecalis

Treatment of root canal infections becomes more challenging due to the extremely high tolerance of Enterococcus faecalis (E. faecalis) to calcium hydroxide (Ca(OH)2). Ginsenoside is a Chinese herbal extract that has been proven to have antimicrobial properties and synergistic activities. And this study evaluated the antibacterial activity of ginsenoside Rh2 in combination with Ca(OH)2 against E. faecalis and its preliminary mechanism of action. Broth microdilution method, checkerboard dilution method, time-inhibition curve, drug resistance assays, scanning electron microscopy, and biofilm inhibition and removal assays indicated that Rh2 in combination with Ca(OH)2 exhibited potent antibacterial activity against E. faecalis. Rh2 exerted significant in vitro antibacterial activity against E. faecalis, with a minimum inhibitory concentration (MIC) of 3.125 μg/mL and minimum bactericidal concentration (MBC) of 6.25 μg/mL, and significantly enhanced the susceptibility of E. faecalis to Ca(OH)2 (FICI = 0.5). Furthermore, cell membrane permeability assays, surface hydrophobicity assays, ATPase activity assays, and intra-biofilm extracellular polysaccharides (EPS) assays revealed that Rh2 and Ca(OH)2 synergistically inhibit bacteria mainly by increasing membrane permeability. Ultimately, cytotoxicity assays showed that Rh2 exhibited only low toxicity, the half maximal inhibitory concentration (IC50) of Rh2 was 19.75 μg/mL. This study confirmed the synergistic antibacterial activities of Rh2 and Ca(OH)2 against E. faecalis. Our findings indicate that the Rh2 and Ca(OH)2 combination may be a promising alternative approach to treating root canal infections.

Highly Efficient AIE-Active palmatine photosensitizer for photodynamic inactivation of Listeria monocytogenes in apple juice preservation

Photodynamic sterilization is a promising alternative to conventional antibacterial approaches with merits of high efficiency and safety. The exploration of aggregation-induced emission (AIE)-type photosensitizers from natural sources is highly valued by researchers and food industry. Herein, the use of palmatine (PA), an aggregation-induced emission-active natural product from traditional Chinese medicine, as photosensitizers for photodynamic inactivation of a tenacious foodborne pathogen of Listeria monocytogenes is investigated. Antibacterial and antibiofilm activity against L. monocytogenes of PA-mediated photodynamic process were first assessed. The results showed that PA-mediated photodynamic process could inhibit the growth of L. monocytogenes, and the minimum bactericidal concentration was determined as 80 μM. At this PA dosing level, well-established biofilms of L. monocytogenes can be effectively destroyed under light irritation. Afterward, cell- and gene-level investigations were conducted to explore the antibacterial mechanism. It is concluded that the exceptional photodynamic antibacterial activity of PA against L. monocytogenes is attributed to the disruption of the cell wall and membrane, increased cell permeability, leakage of functional proteins, and damage to DNA structure. Subsequently, PA-mediated photodynamic process was applied to reduce bacterial activity in apple juice while preserving its quality. Overall, this work highlights the significant potential of PA-mediated photodynamic strategy for controlling foodborne pathogens in food systems.

Green extraction and partial purification of roselle (Hibiscus sabdariffa L.) extracts with high amounts of phytochemicals and in vitro antioxidant and antibacterial effects

The aim of this study is to develop roselle (Hibiscus sabdariffa L.) extracts with high amounts of phytochemicals and in vitro antioxidant and antibacterial effects using green extraction technique. Roselle extract prepared by ultrasonic extraction with 80% ethanol and 1% hydrochloric acid (RSUEH) promoted the highest yield and high total phenolic (5.21 ± 0.05 g% gallic acid equivalent of dried extract), total flavonoid (1.29 ± 0.06 g% quercetin equivalent of dried extract), and total anthocyanin contents (0.21 ± 0.00 and 0.44 ± 0.00 g% cyanidin 3-glucoside equivalent of dried extract determined by pH-differential method with standard calculation and pH-differential method with standard curve of cyanidin 3-glucoside, respectively). From the validated high-performance liquid chromatography analysis, delphinidin-3-sambubioside, delphinidin-3-glucoside, and cyanidin-3-glucoside were found to be the major anthocyanins in roselle extract. This extract exhibited moderate 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging effect (EC50 289.61 ± 0.16 µg/mL) and strong inhibitory effects against Escherichia coli, Staphylococcus aureus, Staphylococcus intermedius, Proteus mirabilis, and Pseudomonas aeruginosa with the inhibitory concentration (IC50) values in the range of 0.15 ± 0.05 to 4.64 ± 0.07 mg/mL and the minimum inhibitory concentration (MIC) values ranged from 1.66 ± 0.06 to 7.11 ± 1.05 mg/mL. From partial purification, fraction 28 (F28) contained higher amounts of all analyzed phytochemicals than roselle extracts and promoted stronger DPPH scavenging effects (EC50 54.88 ± 2.23 µg/mL). F28 showed antibacterial activity with IC50 values against all tested bacteria in the range of 0.19 ± 0.07 to 4.69 ± 0.09 mg/mL, and the MIC values ranged from 2.46 ± 0.08 to 6.24 ± 0.09 mg/mL.

Antibacterial activities of Adina rubella extract enhanced by fermentation and its application in packaging films

Food spoilage caused by pathogens pose great threat to food safety and human health. Plastarch-based packaging films with antibacterial activities provide an effective way to control foodborne pathogens. In this study, microbial fermentation dominated by yeast was used for the first time to increase the antibacterial activity of Adina rubella extract (ARE). The best antimicrobial effect of ARE was observed by fermentation for 9 days. The minimum inhibitory concentration of ARE against Listeria monocytogenes was 3.125 mg/mL. ARE destroyed the structure of the cell wall, increased the permeability of the cell membrane, led to the leakage of nucleic acids, and induced the change of ROS level, which caused cell death of Listeria monocytogenes. ARE-based biodegradable films were prepared and their performance in pork packaging application was evaluated. The films showed effective antimicrobial properties and showed great potential for the development of safe and sustainable food packaging films.

Antibacterial mechanism analysis of resveratrol against Salmonella typhimurium via metabolomics

Salmonella, a common pathogenic bacterium in food, can have a severe impact on food safety and consumer health. At present, Salmonella infection is controlled primarily by the use of antibiotics, which creates unsafe factors for food safety. Thus, finding a natural antibacterial agent is highly practical. In this study, resveratrol was screened from 17 kinds of polyphenols, and its inhibitory mechanism and effects on metabolites of Salmonella typhimurium were investigated to occur through cell wall and membrane damage and metabolomics analysis. The results revealed that the minimum inhibitory concentration of resveratrol against S. typhimurium was 250 μg/mL. After treatment with resveratrol, the lag period of the strain was prolonged, and the cell wall and membrane structure were destroyed. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) further confirmed that resveratrol induced damage to the cell walls and cell membrane. The metabolic profile of S. typhimurium following resveratrol treatment was analysed by gas chromatography‒mass spectrometry. In the metabolome evaluation, we screened 23 differentially abundant metabolites, including 11 upregulated and 12 downregulated metabolites. Eight metabolic pathways of S. typhimurium, including pathways important for amino acid metabolism and the tricarboxylic acid (TCA) cycle, exhibited significant changes after resveratrol treatment. The verification results of the citric acid content, cis-aconitase activity, and ATP content further revealed that the tricarboxylic acid cycle and other related metabolic pathways of S. typhimurium were affected. These results could provide a theoretical possibility for the use of resveratrol as a plant-derived bacteriostatic for food safety problems caused by S. typhimurium. KEY POINTS: • The mechanism of bacteriostasis was studied via metabolomics • Resveratrol causes the death of Salmonella by disrupting the cell wall and membrane.

Effect of co-fermentation of non-Saccharomyces yeasts with Saccharomyces cerevisiae on the quality and flavor of blueberry wine

The pure fermentation with Saccharomyces cerevisiae leads to a limited type and content of volatile aroma compounds in blueberry wine. This study analyzed the effect of three non-Saccharomyces yeasts (Candida glabrata E4, Pichia anomala E1, and Wickerhamomyces anomalus E3) on the quality and flavor of blueberry wine by co-fermenting them with S. cerevisiae NCUF309.2 (the CS, PS, and WS groups, respectively). The results showed that co-fermentation reduced the peak concentration of S. cerevisiae NCUF309.2 or put off the peak time. The total phenol and total flavonoid contents were notably elevated in the PS group compared with S. cerevisiae NCUF309.2 pure fermentation (the S group); the volatile aroma compound contents in the CS group were the highest (1314.33 μg/L), of which alcohols and esters contents increased by 60.29 % and 60.87 %, respectively. This study provides references for improving the quality and flavor of blueberry wine by selecting suitable non-Saccharomyces yeasts.

Antimicrobial and therapeutic potentials of the blackberry extracts against Escherichia coli infection in male albino rats

BACKGROUND

Blackberries have garnered attention recently due to their high concentration of bioactive components like anthocyanin and their health advantages. Therefore, this study aims to determine the bioactive profile, antioxidant and antibacterial effects of blackberry extracts (BBEs). Then, evaluate the protective effect of BBEs (20%, 30% and 40%) in a rat model of 2 mL of 4-8 × 106 Escherichia coli ATTC 25922 strain colony-forming unit mL-1 oral infection on the seventh day of the experiment.

RESULTS

Rats were divided into six groups: G1: control (C-: normal or negative group), G2: (C+: infected or positive group), G3: infected-treated group by 20% BBE, G4: infected-treated group by 30% BBE, G5: infected-treated group by 40% of BBE and G6: infected-treated group by Gentamicin. The results showed that BBE had a high content of total phenolic compounds, flavonoid, anthocyanin contents, and different vitamins (vitamins A, E and C), reaching 450, 186, 58.83 mg 100 g-1, 2.68, 2.14 and 107.46 mg 100g-1 fresh weight, respectively, which showed great antioxidant and antibacterial effects. Therefore, liver enzymes, kidney function and lipid profiles were significantly higher in the infected group than in the control or infected-treated groups. Furthermore, BBE ameliorated inflammation of the intestine and hepatocyte damage compared to the infected control group.

CONCLUSION

These results suggest that consistent intake of BBE might alleviate hepatic inflammation and the gut microbiota in ways that could significantly impact human health. © 2024 Society of Chemical Industry.

A new UiO-66-NH2 MOF-based nano-immobilized DFR enzyme as a biocatalyst for the synthesis of anthocyanidins

Anthocyanidins and anthocyanins are one subclass of flavonoids in plants with diverse biological functions and have health-promoting effects. Dihydroflavonol 4-reductase (DFR) is one of the important enzymes involved in the biosynthesis of anthocyanidins and other flavonoids. Here, a new MOF-based nano-immobilized DFR enzyme acting as a nano-biocatalyst for the production of anthocyanidins in vitro was designed. We prepared UiO-66-NH2 MOF nano-carrier and recombinant DFR enzyme from genetic engineering. DFR@UiO-66-NH2 nano-immobilized enzyme was constructed based on covalent bonding under the optimum immobilization conditions of the enzyme/carrier ratio of 250 mg/g, 37 °C, pH 6.5 and fixation time of 10 min. DFR@UiO-66-NH2 was characterized and its catalytic function for the synthesis of anthocyanidins in vitro was testified using UPLC-QQQ-MS analysis. Compared with free DFR enzyme, the enzymatic reaction catalyzed by DFR@UiO-66-NH2 was more easily for manipulation in a wide range of reaction temperatures and pH values. DFR@UiO-66-NH2 had better thermal stability, enhanced adaptability, longer-term storage, outstanding tolerances to the influences of several organic reagents and Zn2+, Cu2+ and Fe2+ ions, and relatively good reusability. This work developed a new MOF-based nano-immobilized biocatalyst that had a good prospect of application in the green synthesis of anthocyanins in the future.

Novel Bioplastic Based on PVA Functionalized with Anthocyanins: Synthesis, Biochemical Properties and Food Applications

Over the last ten years, researchers' efforts have aimed to replace the classic linear economy model with the circular economy model, favoring green chemical and industrial processes. From this point of view, biologically active molecules, coming from plants, flowers and biomass, are gaining considerable value. In this study, firstly we focus on the development of a green protocol to obtain the purification of anthocyanins from the flower of Callistemon citrinus, based on simulation and on response surface optimization methodology. After that, we utilize them to manufacture and add new properties to bioplastics belonging to class 3, based on modified polyvinyl alcohol (PVA) with increasing amounts from 0.10 to 1.00%. The new polymers are analyzed to monitor morphological changes, optical properties, mechanical properties and antioxidant and antimicrobial activities. Fourier transform infrared spectroscopy (FTIR) spectra of the new materials show the characteristic bands of the PVA alone and a modification of the band at around 1138 cm-1 and 1083 cm-1, showing an influence of the anthocyanins' addition on the sequence with crystalline and amorphous structures of the starting materials, as also shown by the results of the mechanical tests. These last showed an increase in thickening (from 29.92 μm to approx. 37 μm) and hydrophobicity with the concomitant increase in the added anthocyanins (change in wettability with water from 14° to 31°), decreasing the poor water/moisture resistance of PVA that decreases its strength and limits its application in food packaging, which makes the new materials ideal candidates for biodegradable packaging to extend the shelf-life of food. The functionalization also determines an increase in the opacity, from 2.46 to 3.42 T%/mm, the acquisition of antioxidant activity against 2,2-diphenyl-1-picrylhdrazyl and 2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) radicals and, in the ferric reducing power assay, the antimicrobial (bactericidal) activity against different Staphylococcus aureus strains at the maximum tested concentration (1.00% of anthocyanins). On the whole, functionalization with anthocyanins results in the acquisition of new properties, making it suitable for food packaging purposes, as highlighted by a food fresh-keeping test.

Membrane Damage and Metabolic Disruption as the Mechanisms of Linalool against Pseudomonas fragi: An Amino Acid Metabolomics Study

Pseudomonas fragi (P. fragi) is usually detected in low-temperature meat products, and seriously threatens food safety and human health. Therefore, the study investigated the antibacterial mechanism of linalool against P. fragi from membrane damage and metabolic disruption. Results from field-emission transmission electron microscopy (FETEM) and atomic force microscopy (AFM) showed that linalool damage membrane integrity increases surface shrinkage and roughness. According to Fourier transform infrared (FTIR) spectra results, the components in the membrane underwent significant changes, including nucleic acid leakage, carbohydrate production, protein denaturation and modification, and fatty acid content reduction. The data obtained from amino acid metabolomics indicated that linalool caused excessive synthesis and metabolism of specific amino acids, particularly tryptophan metabolism and arginine biosynthesis. The reduced activities of glucose 6-phosphate dehydrogenase (G6PDH), malate dehydrogenase (MDH), and phosphofructokinase (PFK) suggested that linalool impair the respiratory chain and energy metabolism. Meanwhile, genes encoding the above enzymes were differentially expressed, with pfkB overexpression and zwf and mqo downregulation. Furthermore, molecular docking revealed that linalool can interact with the amino acid residues of G6DPH, MDH and PFK through hydrogen bonds. Therefore, it is hypothesized that the mechanism of linalool against P. fragi may involve cell membrane damage (structure and morphology), disturbance of energy metabolism (TCA cycle, EMP and HMP pathway) and amino acid metabolism (cysteine, glutamic acid and citrulline). These findings contribute to the development of linalool as a promising antibacterial agent in response to the food security challenge.

Dietary Sources, Stabilization, Health Benefits, and Industrial Application of Anthocyanins-A Review

Natural phytochemicals are well known to protect against numerous metabolic disorders. Anthocyanins are vacuolar pigments belonging to the parent class of flavonoids. They are well known for their potent antioxidant and gut microbiome-modulating properties, primarily responsible for minimizing the risk of cardiovascular diseases, diabetes, obesity, neurodegenerative diseases, cancer, and several other diseases associated with metabolic syndromes. Berries are the primary source of anthocyanin in the diet. The color and stability of anthocyanins are substantially influenced by external environmental conditions, constraining their applications in foods. Furthermore, the significantly low bioavailability of anthocyanins greatly diminishes the extent of the actual health benefits linked to these bioactive compounds. Multiple strategies have been successfully developed and utilized to enhance the stability and bioavailability of anthocyanins. This review provides a comprehensive view of the recent advancements in chemistry, biosynthesis, dietary sources, stabilization, bioavailability, industrial applications, and health benefits of anthocyanins. Finally, we summarize the prospects and challenges of applications of anthocyanin in foods.

Fabrication and characterization of chitosan/anthocyanin intelligent packaging film fortified by cellulose nanocrystal for shrimp preservation and visual freshness monitoring

In this study, a multi-functional packaging film was fabricated, utilizing the natural polysaccharide chitosan (CS) as the base material, integrating natural blueberry anthocyanin (AN) as pH-responsive indicator, and reinforced with cellulose nanocrystals (CNCs). The implications of addition levels of CNCs on the characteristics of the films were systematically investigated, resulting in that CS-AN-CNCs 9 % film exhibited optimal performance. Specifically, the film showed a substantial enhancement in maximum tensile strength from 15 MPa to 35 MPa; On the other hand, the swelling degree properties, the oxygen permeability and water vapor permeability decreased from 159.2 % to 92.0 %, from 51.7 g/(m2d) to 12.2 g/(m2d), from 31.6 × 10-12 g/(m·s·Pa) to 1.6 × 10-12 g/(m·s·Pa), respectively. Moreover, the CS-AN-CNCs 9 % film exhibited antioxidant, antibacterial, coupled with a color metrically responsive to pH variations, displaying great potential in indicating the shrimp freshness and delaying spoilage. Another notable advantage of the-prepared packaging material lies in its completely biodegradability, therefore meeting the requirement of environmental protection. Therefore, the prepared CS-AN-CNCs film as an intelligent packaging solution with potential applications in food preservation and freshness monitoring applications.

A green method for anthocyanin extraction from Clitoria ternatea flowers cultivated in southern Brazil: Characterization, in vivo toxicity, and biological activity

This study aimed to develop a green method to obtain an anthocyanin-rich edible extract of Clitoria ternatea flowers grown in southern Brazil. The extract was characterized by UHPLC-MSn and analyzed for toxicological potential in an in vivo model, total phenolic content, and biological activities. By using a 23 multivariate design to study the effects of temperature, acidified solvent, and time on the total anthocyanin content (487.25 mg/g), total phenolic content (2242.47 mgGAE/g), it was possible to determine the optimal point (45 °C, 16 min, and 22.5 mL extraction solution). Thirteen anthocyanins and nine non-anthocyanins were quantified. In vivo toxicity assay using Galleria mellonella showed a safe concentration when administered up to 2.2 g of extract per body kg. The extract showed antioxidant activity and antibacterial action against food pathogens, the method proved to have a low environmental impact, in addition to producing an extract with potential for application in food.

Exploring the Antibacterial Potential and Underlying Mechanisms of Prunella vulgaris L. on Methicillin-Resistant Staphylococcus aureus

Prunella vulgaris L. (PV) is a widely distributed plant species, known for its versatile applications in both traditional and contemporary medicine, as well as in functional food development. Despite its broad-spectrum antimicrobial utility, the specific mechanism of antibacterial action remains elusive. To fill this knowledge gap, the present study investigated the antibacterial properties of PV extracts against methicillin-resistant Staphylococcus aureus (MRSA) and assessed their mechanistic impact on bacterial cells and cellular functions. The aqueous extract of PV demonstrated greater anti-MRSA activity compared to the ethanolic and methanolic extracts. UPLC-ESI-MS/MS tentatively identified 28 phytochemical components in the aqueous extract of PV. Exposure to an aqueous extract at ½ MIC and MIC for 5 h resulted in a significant release of intracellular nucleic acid (up to 6-fold) and protein (up to 10-fold) into the extracellular environment. Additionally, this treatment caused a notable decline in the activity of several crucial enzymes, including a 41.51% reduction in alkaline phosphatase (AKP), a 45.71% decrease in adenosine triphosphatase (ATPase), and a 48.99% drop in superoxide dismutase (SOD). Furthermore, there was a decrease of 24.17% at ½ MIC and 27.17% at MIC in tricarboxylic acid (TCA) cycle activity and energy transfer. Collectively, these findings indicate that the anti-MRSA properties of PV may stem from its ability to disrupt membrane and cell wall integrity, interfere with enzymatic activity, and impede bacterial cell metabolism and the transmission of information and energy that is essential for bacterial growth, ultimately resulting in bacterial apoptosis. The diverse range of characteristics exhibited by PV positions it as a promising antimicrobial agent with broad applications for enhancing health and improving food safety and quality.

Studies on the Inhibition Mechanism of Linalyl Alcohol against the Spoilage Microorganism Brochothrix thermosphacta

The aim of this study was to investigate the bacterial inhibitory ability and mechanism of action of linalyl alcohol against B. thermosphacta. Linalyl alcohol causes the leakage of intracellular material by disrupting the cell wall and exposing the hydrophobic phospholipid bilayer, which binds to bacterial membrane proteins and alters their structure. In addition, linalyl alcohol causes cell membrane damage by affecting fatty acids and proteins in the cell membrane. By inhibiting the synthesis of macromolecular proteins, the normal physiological functions of the bacteria are altered. Linalyl alcohol binds to DNA in both grooved and embedded modes, affecting the normal functioning of B. thermosphacta, as demonstrated through a DNA interaction analysis.

Impact of Combination Therapy with Chemical Drugs and Megavoltage X-ray Exposure on Breast Cancer Stem Cells' Viability and Proliferation of MCF-7 and MDA-MB-231 Cell Lines

BACKGROUND

Breast Cancer (BC) is a serious malignancy among women. However, chemotherapy is an important tool for cancer treatments, but the long-term use of chemotherapy drugs may lead to drug resistance and tumor recurrence. Since Breast Cancer Stem Cells (BCSCs) can be the main factor to induce BC treatment resistance and recurrence, investigation of BCSCs signaling pathways can be an effective modality to enhance cancer treatment efficiency.

OBJECTIVE

In this study, the effect of metformin, SB203580, and takinib alone or in combination with radiotherapy on MCF-7 and MDA-MB-231 breast cancer cell lines was evaluated.

METHODS

MCF-7 and MDA-MB-231 breast cancer cell lines were treated with metformin, SB203580, and takinib for 24 or 48 hours, followed by X-ray exposure. The MTT assay and flow cytometry analysis were performed to assess cell growth inhibition and cellular death, CXCr4 expression, and BCSCs, respectively.

RESULTS

The results showed the combination of takinib/SB203580 with radiotherapy to remarkably reduce the CXCR4 expression and BCSCs levels in the MCF-7 cell line. Also, the concurrent administration of takinib/metformin/radiotherapy significantly reduced BCSCs and CXCR4 metastatic markers in the MDA-MB- 231 cells. Since the MAPK signaling pathway has an important role in inducing drug resistance and cell proliferation, the use of SB203580 as an inhibitor of p38 MAPK can improve breast cancer treatment. Furthermore, metformin and ionizing radiation by suppression of the mTOR signaling pathway can control AMPK activation and cellular proliferation.

CONCLUSION

Anti-cancer and cytotoxic effects of metformin can be effective in this strategy. In conclusion, the combination of conventional chemotherapeutic drugs, including SB203580, metformin, and takinib with X-ray exposure can be a new approach to diminish the drug resistance of breast cancer.

Active and Intelligent Biodegradable Packaging Based on Anthocyanins for Preserving and Monitoring Protein-Rich Foods

Currently, active and intelligent packaging has been developed to solve the spoilage problem for protein-rich foods during storage, especially by adding anthocyanin extracts. In such a film system, the antioxidant and antibacterial properties were dramatically increased by adding anthocyanins. The physicochemical properties were enhanced through interactions between the active groups in the anthocyanins and reactive groups in the polymer chains. Additionally, the active and intelligent film could monitor the spoilage of protein-rich foods in response to pH changes. Therefore, this film could monitor the sensory acceptance and extend the shelf life of protein-rich foods simultaneously. In this paper, the structural and functional properties of anthocyanins, composite actions of anthocyanin extracts and biomass materials, and reinforced properties of the active and intelligent film were discussed. Additionally, the applications of this film in quality maintenance, shelf-life extension, and quality monitoring for fresh meat, aquatic products, and milk were summarized. This film, which achieves high stability and the continuous release of anthocyanins on demand, may become an underlying trend in packaging applications for protein-rich foods.

Identification of candidate genes associated with less-photosensitive anthocyanin phenotype using an EMS mutant (pind) in eggplant (Solanum melongena L.)

Eggplant (Solanum melongena L.) is a highly nutritious and economically important vegetable crop. However, the fruit peel of eggplant often shows poor coloration owing to low-light intensity during cultivation, especially in the winter. The less-photosensitive varieties produce anthocyanin in low light or even dark conditions, making them valuable breeding materials. Nevertheless, genes responsible for anthocyanin biosynthesis in less-photosensitive eggplant varieties are not characterized. In this study, an EMS mutant, named purple in the dark (pind), was used to identify the key genes responsible for less-photosensitive coloration. Under natural conditions, the peel color and anthocyanin content in pind fruits were similar to that of wildtype '14-345'. The bagged pind fruits were light purple, whereas those of '14-345' were white; and the anthocyanin content in the pind fruit peel was significantly higher than that in '14-345'. Genetic analysis revealed that the less-photosensitive trait was controlled by a single dominant gene. The candidate gene was mapped on chromosome 10 in the region 7.72 Mb to 11.71 Mb. Thirty-five differentially expressed genes, including 12 structural genes, such as CHS, CHI, F3H, DFR, ANS, and UFGT, and three transcription factors MYB113, GL3, and TTG2, were identified in pind using RNA-seq. Four candidate genes EGP21875 (myb domain protein 113), EGP21950 (unknown protein), EGP21953 (CAAX amino-terminal protease family protein), and EGP21961 (CAAX amino-terminal protease family protein) were identified as putative genes associated with less-photosensitive anthocyanin biosynthesis in pind. These findings may clarify the molecular mechanisms underlying less-photosensitive anthocyanin biosynthesis in eggplant.

Antimicrobial Activity and Mechanisms of Walnut Green Husk Extract

Walnut green husks (WGHs), by-products of walnut production, are believed to possess antimicrobial properties, making them a potential alternative to antibiotics. In this study, the antibacterial activities of three extracts, derived from WGH, against Staphylococcus aureus, Bacillus subtilis, and Escherichia coli were investigated, and the antibacterial mechanisms of an anhydrous ethanol extract of WGH (WGHa) were examined. The results showed that WGHa exhibited inhibitory effects on all tested bacteria. The ultrahigh-performance liquid chromatography-tandem mass spectrometry analysis revealed that the major active compounds present in WGHa were terpenoids, phenols, and flavonoids. Treatment with WGHa resulted in the leakage of intracellular ions and alkaline phosphatase; a reduction in intracellular ATP content, ATPase activity, and nucleic acid content; as well as cellular metabolic viability. The transmission electron microscopy images showed varying degrees of cell deformation and membrane damage following WGHa treatment. The transcriptome sequencing and differentially expressed gene enrichment analyses revealed an up-regulation in pathways associated with RNA degradation, translation, protein export, and oxidative phosphorylation. Conversely, pathways involved in cell movement and localization, as well as cell wall organization and carbohydrate transport, were found to be down-regulated. These findings suggest that WGHa alters cell membrane permeability and causes damage to the cell wall. Additionally, WGHa interferes with cellular energy metabolism, compromises RNA integrity, and induces DNA replication stress, consequently inhibiting the normal growth and proliferation of bacteria. These findings unveiled the antimicrobial mechanisms of WGHa, highlighting its potential application as an antibiotic alternative.

Enhancing the growth of thermophilic Bacillus licheniformis YYC4 by low-intensity fixed-frequency continuous ultrasound

The effect of low-intensity fixed-frequency continuous ultrasound (LIFFCU) on the growth of Bacillus licheniformis YYC4 was investigated. The changes in morphology and activity of the organism, contributing to the growth were also explored. Compared with the control, a significant increase (48.95%) in the biomass of B. licheniformis YYC4 (at the logarithmic metaphase) was observed following the LIFFCU (28 kHz, 1.5 h and 120 W (equivalent to power density of 40 W/L)) treatment. SEM images showed that ultrasonication caused sonoporation, resulting in increased membrane permeability, evidenced by increase in cellular membrane potential, electrical conductivity of the culture, extracellular protein and nucleic acid, and intracellular Ca2+ content. Furthermore, LIFFCU action remarkably increased the extracellular protease activity, volatile components of the culture medium, microbial metabolic activity, and spore germination of the strain. Therefore, LIFFCU could be used to efficiently promote the growth of targeted microorganisms.

Vaccinium uliginosum and Vaccinium myrtillus-Two Species-One Used as a Functional Food

Vaccinium uliginosum L. (commonly known as bog bilberry) and Vaccinium myrtillus L. (commonly known as bilberry) are species of the genus Vaccinium (family Ericaceae). The red-purple-blue coloration of blueberries is attributed largely to the anthocyanins found in bilberries. Anthocyanins, known for their potent biological activity as antioxidants, have a significant involvement in the prophylaxis of cancer or other diseases, including those of metabolic origin. Bilberry is the most important economically wild berry in Northern Europe, and it is also extensively used in juice and food production. A review of the latest literature was performed to assess the composition and biological activity of V. uliginosum and V. myrtillus. Clinical studies confirm the benefits of V. uliginosum and V. myrtillus supplementation as part of a healthy diet. Because of their antioxidant, anti-inflammatory, anti-cancer, and apoptosis-reducing activity, both bog bilberries and bilberries can be used interchangeably as a dietary supplement with anti-free radical actions in the prevention of cancer diseases and cataracts, or as a component of sunscreen preparations.

A multi-omics analysis strategy reveals the molecular mechanism of the inhibition of Escherichia coli O157:H7 by anthocyanins from Aronia melanocarpa and its application

Water pollution causes the propagation of pathogenic microorganisms, which poses a serious threat to human life. Escherichia coli O157:H7, as a representative organism that can directly exhibit molecular response to stress, was selected as the indicator bacteria for the study. Tandem mass tag (TMT) quantitative proteomics and non-targeted metabolomics were used to study the response of Escherichia coli O157:H7 to Aronia melanocarpa anthocyanin (AMA) treatment. The results showed that 628 proteins and 1338 metabolites changed significantly after treatment with AMAs. According to bioinformatics analysis, integrated proteomics and metabolomics analysis differentially expressed proteins (DEPs) and metabolites participate in pyruvate metabolism, glycolysis/gluconeogenesis, alanine, aspartate and glutamate metabolism and the pentose phosphate pathway. This study preliminarily proposed the inhibition mechanism of AMAs on Escherichia coli O157:H7 from the perspective of multi-omics, providing a theoretical basis for the application of natural preservatives in fresh cut vegetables.

Antibacterial mechanism of areca nut essential oils against Streptococcus mutans by targeting the biofilm and the cell membrane

Introduction

Dental caries is one of the most common and costly biofilm-dependent oral diseases in the world. Streptococcus mutans is the major cariogenic pathogen of dental caries. S. mutans synthesizes extracellular polysaccharides by autologous glucosyltransferases, which then promotes bacterial adhesion and cariogenic biofilm formation. The S. mutans biofilm is the principal target for caries treatment. This study was designed to explore the antibacterial activity and mechanisms of areca nut essential oil (ANEO) against S. mutans.

Methods

The ANEOs were separated by negative pressure hydro-distillation. The Kirby-Bauer method and broth microdilution method were carried out to evaluate the antibacterial activity of different ANEOs. The antibacterial mechanism was revealed by crystal violet staining, XTT reduction, microbial adhesion to hydrocarbon test, extracellular polysaccharide production assay, glucosyltransferase activity assay, lactate dehydrogenase leaking, propidium iodide staining and scanning electron microscopy (SEM). The cytotoxicity of ANEOs was determine by MTT assay.

Results

The ANEOs separated at different temperatures exhibited different levels of antibacterial activity against S. mutans, and the ANEO separated at 70°C showed the most prominent bacteriostatic activity. Anti-biofilm experiments showed that the ANEOs attenuated the adhesion ability of S. mutans by decreasing the surface hydrophobicity of the bacteria, prevented S. mutans biofilm formation by inhibiting glucosyltransferase activity, reducing extracellular polysaccharide synthesis, and reducing the total biofilm biomass and activity. SEM further demonstrated the destructive effects of the ANEOs on the S. mutans biofilm. Cell membrane-related experiments indicated that the ANEOs destroyed the integrity of the cell membrane, resulting in the leakage of lactic dehydrogenase and nucleic acids. SEM imaging of S. mutans cell showed the disruption of the cellular morphology by the ANEOs. The cytotoxicity assay suggested that ANEO was non-toxic towards normal oral epithelial cells.

Discussion

This study displayed that ANEOs exerted antibacterial activity against S. mutans primarily by affecting the biofilm and disrupting the integrity of the cell membrane. ANEOs has the potential to be developed as an antibacterial agent for preventing dental caries. Additionally, a new method for the separation of essential oil components is presented.

Metabolic perturbations and key pathways associated with the bacteriostatic activity of Clitoria ternatea flower anthocyanin fraction against Escherichia coli

Clitoria ternatea flowers are rich in anthocyanins and possess various biological activities. Specifically, the antibacterial mechanism of action of C. ternatea anthocyanins remains unknown and was investigated in Escherichia coli . A time-kill assay was used to assess the antibacterial activity and the metabolic perturbations in E. coli were investigated utilizing liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. Pathway analyses were carried out for metabolites showing ≥2-fold changes. The anthocyanin fraction remarkably reduced the growth of E. coli at 4 h by 95.8 and 99.9 % at minimum inhibitory concentration (MIC) and 2× MIC, respectively. The anthocyanin fraction (MIC) had a bacteriostatic effect and was shown to have perturbed glycerophospholipids (1-acyl-sn-glycero-3-phosphoethanolamine, phosphatidylglycerol, diacylglycerol and cardiolipin), amino acids (valine, tyrosine and isoleucine) and energy (ubiquinone and NAD) metabolites at 1 and 4 h. This study demonstrated significant metabolic perturbations of the glycerophospholipid, amino acid and energy metabolism, with these being the key pathways involved in the bacteriostatic activity of anthocyanins from C. ternatea, which may have promise as bacteriostatic agents for E. coli -related infections.

The mechanism of whey protein and blueberry juice mixed system fermented with Lactobacillus inhibiting Escherichia coli during storage

The aim of this study was to identify the antimicrobial effect and mechanism of whey protein and blueberry juice mixed systems fermented with Lactobacillus against Escherichia coli during storage. The whey protein and blueberry juice mixed systems were fermented with L. casei M54, L. plantarum 67, S. thermophiles 99 and L. bulgaricus 134 and had different antibacterial activities against E. coli during storage. The antimicrobial activity of the mixed whey protein and blueberry juice mixture systems was the highest, with an inhibition zone diameter of approximately 230 mm, compared with the whey protein or blueberry juice systems alone. There were no viable E. coli cells 7 h after treatment with of the whey protein and blueberry juice mixed systems as determined by survival curve analysis. Analysis of the inhibitory mechanism showed that the release of alkaline phosphatase, electrical conductivity, protein and pyruvic acid contents, and aspartic acid transaminase and alanine aminotransferase activity in E. coli increased. These results demonstrated that these mixed systems fermented with Lactobacillus, especially those containing blueberries, could inhibit the growth of E. coli and even cause cell death by destroying the cell membrane and cell wall.

Protective Effect of Hirsutidin against Rotenone-Induced Parkinsonism via Inhibition of Caspase-3/Interleukins-6 and 1β

A participant of the chemical family recognized as anthocyanins, hirsutidin is an O-methylated anthocyanidin. It is a natural substance, i.e., existing in Catharanthus roseus (Madagascar periwinkle), the predominant component in petals, as well as callus cultures. The literature review indicated a lack of scientifically verified findings on hirsutidin's biological activities, particularly its anti-Parkinson's capabilities. Using the information from the previous section as a reference, a present study has been assessed to evaluate the anti-Parkinson properties of hirsutidin against rotenone-activated Parkinson's in experimental animals. For 28 days, rats received hirsutidin at a dose of 10 mg/kg and rotenone at a dose of 0.5 mg/kg s.c. to test the neuroprotective effects. The hirsutidin was given 1 h before the rotenone. Behavioral tests, including the rotarod test, catalepsy, Kondziela's inverted screen activity, and open-field analysis, were performed. The levels of neurotransmitters (5-HT, DOPAC, 5-HIAA, dopamine, and HVA), neuroinflammatory markers (TNF-α, IL-6, IL-1β, caspase-3), an endogenous antioxidant, nitrite content, and acetylcholine were measured in all the rats on the 29th day. Hirsutidin exhibited substantial behavioral improvement in the rotarod test, catalepsy, Kondziela's inverted screen activity, and open-field test. Furthermore, hirsutidin restored neuroinflammatory markers, cholinergic function, nitrite content, neurotransmitters, and endogenous antioxidant levels. According to the study, hirsutidin has anti-inflammatory and antioxidant characteristics. As a result, it implies that hirsutidin may have anti-Parkinsonian effects in rats.

Hirsutidin Prevents Cisplatin-Evoked Renal Toxicity by Reducing Oxidative Stress/Inflammation and Restoring the Endogenous Enzymatic and Non-Enzymatic Level

Recent research has shown that phytocomponents may be useful in the treatment of renal toxicity. This study was conducted to evaluate the renal disease hirsutidin in the paradigm of renal toxicity induced by cisplatin. Male Wistar rats were given cisplatin (3 mg/kg body weight/day, for 25 days, i.p.) to induce renal toxicity. Experimental rats were randomly allocated to four different groups: group I received saline, group II received cisplatin, group III received cisplatin + hirsutidin (10 mg/kg)and group IV (per se)received hirsutidin (10 m/kg)for 25 days. Various biochemical parameters were assessed, oxidative stress (superoxide dismutase (SOD), glutathione transferase (GSH), malonaldehyde (MDA) and catalase (CAT)), blood-chemistry parameters (blood urea nitrogen (BUN) and cholesterol), non-protein-nitrogenous components (uric acid, urea, and creatinine), and anti-inflammatory-tumor necrosis factor-α (TNF-α), interleukin-1β(IL-1β). IL-6 and nuclear factor-kB (NFκB) were evaluated and histopathology was conducted. Hirsutidin alleviated renal injury which was manifested by significantly diminished uric acid, urea, urine volume, creatinine, and BUN, compared to the cisplatin group. Hirsutidin restored the activities of several antioxidant enzyme parameters—MDA, CAT, GSH, and SOD. Additionally, there was a decline in the levels of inflammatory markers—TNF-α, IL-1β, IL-6, and NFκB—compared to the cisplatin group. The current research study shows that hirsutidin may act as a therapeutic agent for the treatment of nephrotoxicity induced by cisplatin.

Analysis of sucrose addition on the physicochemical properties of blueberry wine in the main fermentation

Introduction

Harvested blueberries can be processed into wine to extend their shelf life and increase their commercial value. In order to produce fruit wine, external sugar is often added prior to fermentation to increase the final alcohol content to a target of 8-12% (v/v) to meet consumer expectations.

Method

we explore the effect of 8-14% (w/w) sucrose on the physicochemical properties of blueberry wine throughout the main fermentation process. We monitor changes of alcohol content, sugar, color, phenol, acidity, anthocyanin, and odor.

Results and discussion

We notice that sucrose affects the fermentation process and physicochemical composition of the final blueberry wine by fermentation rate, fermentation color and protection of functional substances protection. Additional sucrose extends the total time of fermentation, and increases wine acidity. The color of the wine is also affected, with added sugar darkening and yellowing the final product. Interestingly, the sucrose has a protective effect on anthocyanin levels, although total anthocyanin levels are still substantially reduced following fermentation. Finally, the additional sugar increases accumulation of volatile odor components, particularly alcohols and esters, as measured by an electronic nose. We conclude that an addition of 12% sucrose produces wine with superior physicochemical properties of alcohol, anthocyanin loss and odor relative to other conditions tested and recommend this approach to commercial manufacturers.

Salt tolerance evolution facilitates antibiotic resistome in soil microbiota: Evidences from dissemination evaluation, hosts identification and co-occurrence exploration

Salinity is considered as one of the vital factors affecting the profiles of antibiotic resistance genes (ARGs) in soils, whereby its roles in shaping the antibiotic resistome were still poorly understood. Here, metagenomic analysis was conducted to track the ARGs distributions and dissemination in soils during salt accumulation and desalinization processes. Neutral-salt accumulation for 45 and 90 days significantly increased the relative abundances of ARGs and mobile genetic elements (MGEs) carrying antibiotic resistance contigs (ARCs). The ARGs within antibiotic efflux and target protection families primarily carried by Streptomyces, Nocardioides, Rhodanobacter and Monashia were largely enriched by salinity. The ARGs subtypes of the resistance-nodulation-division (RND) family, ATP-binding cassette (ABC) family, rRNA methyltransferase and other efflux were closely associated with MGEs, contributing to the enrichment of ARGs. Moreover, the ARGs subtypes and transposons were genetically linked with the salt-tolerance mechanisms of organic osmolyte transporters and K⁺ uptake proteins on the same ARC, demonstrating the coselection of ARGs and halotolerant genes. Furthermore, the antibiotic resistome could recover to a normal state after the prolonged incubation by alleviating salt stress. Nevertheless, the acquisition of ARGs by opportunistic pathogens after salt treatment was increased, serving to prioritize further efforts on the health risks correlated with resistance propagation and human exposure in saline soils.

Antibacterial activity and mechanism of flavonoids from Chimonanthus salicifolius S. Y. Hu. and its transcriptome analysis against Staphylococcus aureus

Introduction

Chimonanthus salicifolius S. Y. Hu. (FCS) possess many biological activities, but the antibacterial activity and underlying mechanisms of flavonoids from Chimonanthus salicifolius S. Y. Hu. (FCS) is still unknown.

Method

Maximum diameter of inhibition zone (DIZ), maximum diameter of inhibition zone (DIZ), the lowest minimum inhibition concentration (MIC), and the lowest minimum bactericide concentration (MBC) were used to detect the antibacterial activity. Meanwhile, related enzyme activities, the transcriptome analysis and quantitative RT-PCR were used to investigate the antibacterial activity mechanisms.

Results

The results showed that FCS (with a purity of 84.2 ± 2.0%) has potential effects on tested strains with the maximum diameter of inhibition zone (DIZ) was 15.93 ± 2.63 mm, the lowest minimum inhibition concentration (MIC) was 1.56 mg/ml and the lowest minimum bactericide concentration (MBC) was 6.25 mg/ml. In addition, the bacterial growth curve test, release of extracellular alkaline phosphatase (AKP), loss of intracellular components, DNA damage and transmission electron microscope (TEM) suggested that FCS could destroy the cell wall and membrane, cause the loss of intracellular substance, cause DNA damage and even lead to cell death. Moreover, the antibacterial mechanism of FCS against Staphylococcus aureus (S. aureus, Gram-positive bacteria) was further confirmed by the transcriptome analysis and quantitative RT-PCR at the molecular level for the first time. A total of 671 differentially expressed genes (DEGs) were identified after treated with FCS (1/2 MIC), with 338 and 333 genes showing up-regulation and down-regulation, respectively. The highlighted changes were those related to the biosynthesis of bacteria wall and membrane, DNA replication and repair, and energy metabolism.

Discussion

Overall, our research provides theoretical guidance for the application of FCS, which is expected to be potentially used as a natural antimicrobial agent in food safety.

Bioassay-Guided Isolation and Identification of Antibacterial Components against Escherichia coli from Industrial Hemp Leaves

Industrial hemp leaves have raised much interest in nutraceuticals and functional foods areas. To expand its application ranges, the antibacterial activities of industrial hemp leaf extract on Escherichia coli, Staphylococcus aureus, and Bacillus cereus were evaluated and the active components were screened. As a result, the industrial hemp leaf extract was found to have strong bacteriostatic effects on E. coli and S. aureus. Bioassay-guided fractionation and isolation from fractions active against E. coli were conducted. Two compounds, cannabidivarinic acid and cannabidiolic acid, were firstly recognized by analytical HPLC by comparing the retention times and UV spectra with standards and later isolated using preparative HPLC. Moreover, the antibacterial mechanisms of cannabidivarinic acid and cannabidiolic acid were investigated by testing the alkaline phosphatase activity, β-galactosidase activity, conductivity, proteins leakage, nucleic acid leakage, and scanning electron microscope observation. The results demonstrated that cannabidivarinic acid and cannabidiolic acid could destroy the cell wall and membrane of E. coli, resulting in the inhibition of enzyme activity and leakage of contents. They could damage the bacteria cell envelope as well. Presented results pointed out cannabidivarinic acid and cannabidiolic acid as promising natural bacteriostatic agents for the food, pharmaceutical, and cosmetic industry.

Antimicrobial effect of phenolic-rich jaboticaba peel aqueous extract on Staphylococcus aureus and Escherichia coli

Abstract Jaboticaba peels are an important source of health-benefit and antimicrobial compounds. The present work aims to evaluate concentration of polyphenolics and the mode of action of aqueous extract from jaboticaba peels against Staphylococcus aureus and Escherichia coli. Jaboticaba peel extract showed minimum inhibitory concentration and minimum bactericidal concentration against S. aureus of 5.1 g L-1 and 10.1 g L-1, respectively; meanwhile, against E. coli the parameters were 2.0 g L-1 and 3.4 g L-1. Kinetics of viable cell counts indicated a bacteriolytic action against both bacteria and Scanning Electron Microscopy (SEM) showed that jaboticaba peel extract causes subtle morphological changes in bacterial cells. Concentration of total polyphenols in the extract was 1535.04±36.05 mg of gallic acid equivalent (GAE) mL-1, monomeric anthocyanins was 14.52 ± 0.98 mg of cyanidin 3-glucoside mL-1, condensed tannins was 0.49 ± 0.05 mg of epicatechin equivalent mL-1 and phenolic acids was 80.04 ± 4.11 mg of caffeic acid equivalent (CAE) mL-1, which have demonstrated well-documented antibacterial activity. In conclusion, jaboticaba peel aqueous extract may be an interesting natural preservative to control Gram-positive and Gram-negative bacteria growth when interacting with the bacteria cell wall.

Anthocyanins from Malus spp. inhibit the activity of Gymnosporangium yamadae by downregulating the expression of WSC, RLM1, and PMA1

Malus plants are frequently devastated by the apple rust caused by Gymnosporangium yamadae Miyabe. When rust occurs, most Malus spp. and cultivars produce yellow spots, which are more severe, whereas a few cultivars accumulate anthocyanins around rust spots, forming red spots that inhibit the expansion of the affected area and might confer rust resistance. Inoculation experiments showed that Malus spp. with red spots had a significantly lower rust severity. Compared with M. micromalus, M. 'Profusion', with red spots, accumulated more anthocyanins. Anthocyanins exhibited concentration-dependent antifungal activity against G. yamadae by inhibiting teliospores germination. Morphological observations and the leakage of teliospores intracellular contents evidenced that anthocyanins destroyed cell integrity. Transcriptome data of anthocyanins-treated teliospores showed that differentially expressed genes were enriched in cell wall and membrane metabolism-related pathways. Obvious cell atrophy in periodical cells and aeciospores was observed at the rust spots of M. 'Profusion'. Moreover, WSC, RLM1, and PMA1 in the cell wall and membrane metabolic pathways were progressively downregulated with increasing anthocyanins content, both in the in vitro treatment and in Malus spp. Our results suggest that anthocyanins play an anti-rust role by downregulating the expression of WSC, RLM1, and PMA1 to destroy the cell integrity of G. yamadae.

Effects of cinnamon essential oil on the physiological metabolism of Salmonella enteritidis

Food safety and health are the themes of today's society. As a class of foodborne pathogens, Salmonella enteritidis has become one of the common zoonotic pathogens. Because chemical preservatives have certain harmfulness and have been questioned, it is particularly important to find green and safe natural preservatives. The advantages of plant essential oils (EOs) are that they are green and safe, have a wide range of antibacterials, and are not easy to form drug resistance. In recent years, studies have found that EOs have excellent antibacterial activity, but their antibacterial mechanism has not been conclusive, which has certain limitations in their application in the food field. Cinnamon essential oil (CEO) extracted from dried cinnamon is a secondary metabolite of cells and a very important natural food flavor. More importantly, it is non-toxic to the human body and has been proven to have a good antibacterial effect, but its antibacterial mechanism is still unclear. Therefore, it was of great practical significance to carry out the research on the antibacterial mechanism of CEO on S. enteritidis. In this work, S. enteritidis was used as the test bacteria, and CEO was selected as the antibacterial agent to study the antibacterial mechanisms. By studying the physiological metabolism of S. enteritidis cells by CEO, the influence of CEO on the bacteriostatic mechanism of S. enteritidis was systematically elucidated. The study found that CEO treatment would reduce the activity of bacterial metabolism. It is mainly reflected in the following three aspects: first, the activity of key enzymes in TCA circulation is inhibited, thus affecting the respiration of S. enteritidis. Second, it affects the level of energy metabolism by inhibiting the content of adenosine triphosphate (ATP) and the activity of ATPase. Finally, it can affect the physiological metabolism of bacteria by inhibiting the metabolism of proteins and other substances. Therefore, this article was expected to provide a theoretical basis for the development of new natural food preservatives and the prevention and control of S. enteritidis.

Purification of Polysaccharides from Orostachys cartilaginous Cell Cultures by Macroporous Resin Absorption and Bioactivities of the Purified Polysaccharides

Orostachys cartilaginous is a traditional herbal medicine and its cell cultures contain large amounts of polysaccharides. To utilize the cultured O. cartilaginous cells, this study purified the crude polysaccharides of O. cartilaginous cells by macroporous resin absorption and optimized the purification process in the experiment of orthogonal design with four factors (sample concentration and volume, and eluent concentration and volume) and three levels; the antibacterial and anti-cancer effects of the purified polysaccharides (OTP) were further examined. The results showed that polysaccharide purity reached 95 % in the optimized group, i. e., 1.6 mg/mL of sample (crude polysaccharides) concentration, 3.0 bed volume (BV) of sample volume, 65 % eluent (ethanol) concentration, and 3.0 BV of eluent volume. In the antibacterial experiment, the growth of three bacterial species, i. e., Pseudomonas aeruginosa, Staphylococcus aureus, and Bacillus subtilis was inhibited by OTP, whereas that of Escherichia coli was not affected; the largest diameter of the inhibitory zone was found on B. subtilis; the extracellular alkaline phosphatase activity and the electrical conductivity, nucleic acid, and protein levels of B. subtilis increased after OTP treatment, indicating that the inhibition of B. subtilis growth was caused by the leakage of cell contents. In the anti-cancer experiment, OTP decreased the cell viabilities of the tested human cancer cells, i. e., AGS (gastric cancer), HCT116 (colon cancer), HepG2 (liver cancer), and HeLa (cervical cancer), and the highest inhibitory effect was on HCT116. OTP promoted HCT116 apoptosis and affected the expression of apoptosis-related proteins, i. e., the expression of B-cell lymphoma-2 decreased and that of bcl-2 associated X protein, cytochrome c, caspase 9 and caspase 3 increased. The findings of the present study suggest that O. cartilaginous cell cultures have a potential application in food or drug production.

Inhibition of Listeria monocytogenes and Escherichia coli O157:H7 Growth by Ohelo Berry (Vaccinium calycinum) Fractions: Anthocyanins, Non-Anthocyanin Phenolics, and Organic Acids

Listeria monocytogenes and Escherichia coli O157:H7 are common causes of foodborne illness worldwide. Ohelo berry (Vaccinium calycinum) juice was found to possess inhibitory activity against L. monocytogenes. This study aimed to determine which constituents of ohelo berry have the most potent antimicrobial effects. The crude extract of ohelo berry was separated into sugar plus organic acids (F1), non-anthocyanin phenolics (F2), and anthocyanins (F3). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the fractions were determined against L. monocytogenes and E. coli O157:H7. The results demonstrated that F3 contained the highest concentrations of total phenolics and anthocyanins. All fractions caused a significant growth reduction in two bacteria compared to controls. F1 at native pH had the same MIC (1.39/0.36 Bx/acid) and MBC (5.55/1.06 Bx/acid) against the two bacteria, while neutralized F1 did not inhibit the growth of either pathogen. The MIC of F3 against L. monocytogenes was 13.69 mg/L cyanidin-3-glucoside equivalent, which was not affected by neutralization. Besides, L. monocytogenes was more sensitive than E. coli O157:H7 to all fractions. These findings suggest that both phenolics and organic acids contribute to the antimicrobial properties of ohelo berry, which have the potential to be used as natural food preservatives.

Antibacterial Mechanism of Chitosan-Gentamicin and Its Effect on the Intestinal Flora of Litopenaeus vannamei Infected with Vibrio parahaemolyticus

To explore the application of chitosan-gentamicin conjugate (CS-GT) in inhibiting Vibrio parahaemolyticus (V. parahaemolyticus), which is an important pathogen in aquatic animals worldwide, the antimicrobial activity of CS-GT and the effects of a CS-GT dose on the intestine histopathology and intestinal flora of V. parahaemolyticus-infected shrimps were explored. The results showed that CS-GT possessed broad-spectrum antibacterial activity, with minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and half inhibitory concentration (IC50) of 20.00 ± 0.01, 75.00 ± 0.02 and 18.72 ± 3.17 μg/mL for V. parahaemolyticus, respectively. Further scanning electron microscope and cell membrane damage analyses displayed that the electrostatic interaction of CS-GT with cell membrane strengthened after CS grafted GT, resulting in leakage of nucleic acid and electrolytes of V. parahaemolyticus. On the other hand, histopathology investigation indicated that high (100 mg/kg) and medium (50 mg/kg) doses of CS-GT could alleviate the injury of a shrimp's intestine caused by V. parahaemolyticus. Further 16S rRNA gene sequencing analysis found high and medium dose of CS-GT could effectively inhabit V. parahaemolyticus invasion and reduce intestinal dysfunction. In conclusion, CS-GT possesses good antibacterial activity and could protect shrimps from pathogenic bacteria infection.

Antibacterial Activity of Thymoquinone Against Shigella flexneri and Its Effect on Biofilm Formation

Thymoquinone (TQ) has been demonstrated to have anti-cancer, anti-inflammatory, antioxidant, and anti-diabetic activities. Shigella flexneri is the main pathogen causing shigellosis in developing countries. In this study, the antibacterial activity of TQ against S. flexneri and its possible antibacterial mechanism were studied. In addition, the inhibitory effect of TQ on the formation of S. flexneri biofilm was also investigated. The results showed that both the minimum inhibitory concentration and the minimum bactericidal concentration of TQ against S. flexneri ATCC 12022 were 0.2 mg/mL. After treatment with TQ at 0.4 mg/mL in Luria-Bertani broth for 3 h, or treatment with 0.2 mg/mL TQ in phosphate-buffered saline for 60 min, the number of S. flexneri (initial number is 6.5 log colony-forming units/mL) dropped below the detection limit. TQ also displayed good antibacterial activity in contaminated lettuce juice. TQ caused an increase in intracellular reactive oxygen species level, a decrease in intracellular adenosine triphosphate (ATP) concentration, a change in the intracellular protein, damage to cell membrane integrity and changes in cell morphology. In addition, TQ showed the ability to inhibit the formation of S. flexneri biofilm; treatment resulted in a decrease in the amount of biofilm and extracellular polysaccharides, and the destruction of biofilm structure. These findings indicated that TQ had strong antimicrobial and antibiofilm activities and a potential to be applied in the fruit and vegetable processing industry or other food industries to control S. flexneri.