The Effect of Chlorogenic Acid on Bacillus subtilis Based on Metabolomics

Physicochemical Properties, Stability, and Functionality of Non-Covalent Ternary Complexes Fabricated with Pea Protein, Hyaluronic Acid and Chlorogenic Acid

The aim of this study was to prepare and characterize stable non-covalent ternary complexes based on pea protein (PP, 0.5%), hyaluronic acid (HA, 0.125%), and chlorogenic acid (CA, 0~0.03%). The ternary complexes were comprehensively evaluated for physicochemical attributes, stability, emulsifying capacities, antioxidant properties, and antimicrobial efficacy. PP-HA binary complexes were first prepared at pH 7, and then CA was bound to the binary complexes, as verified by fluorescence quenching. Molecular docking elucidated that PP interacted with HA and CA through hydrogen bonding, hydrophobic and electrostatic interactions. The particle size of ternary complexes initially decreased, then increased with CA concentration, peaking at 0.025%. Ternary complexes demonstrated good stability against UV light and thermal treatment. Emulsifying activity of complexes initially decreased and then increased, with a turning point of 0.025%, while emulsion stability continued to increase. Complexes exhibited potent scavenging ability against free radicals and iron ions, intensifying with higher CA concentrations. Ternary complexes effectively inhibited Staphylococcus aureus and Escherichia coli, with inhibition up to 0.025%, then decreasing with CA concentration. Our study indicated that the prepared ternary complexes at pH 7 were stable and possessed good functionality, including emulsifying properties, antioxidant activity, and antibacterial properties under certain concentrations of CA. These findings may provide valuable insights for the targeted design and application of protein-polysaccharide-polyphenol complexes in beverages and dairy products.

Unleashing the power of chlorogenic acid: exploring its potential in nutrition delivery and the food industry

In the contemporary era, heightened emphasis on health and safety has emerged as a paramount concern among individuals with food. The concepts of "natural" and "green" have progressively asserted dominance in the food consumption market. Consequently, through continuous exploration and development, an escalating array of natural bioactive ingredients is finding application in both nutrition delivery and the broader food industry. Chlorogenic acid (CGA), a polyphenolic compound widely distributed in various plants in nature, has garnered significant attention. Abundant research underscores CGA's robust biological activity, showcasing notable preventive and therapeutic efficacy across diverse diseases. This article commences with a comprehensive overview, summarizing the dietary sources and primary biological activities of CGA. These encompass antioxidant, anti-inflammatory, antibacterial, anti-cancer, and neuroprotective activities. Next, a comprehensive overview of the current research on nutrient delivery systems incorporating CGA is provided. This exploration encompasses nanoparticle, liposome, hydrogel, and emulsion delivery systems. Additionally, the article explores the latest applications of CGA in the food industry. Serving as a cutting-edge theoretical foundation, this paper contributes to the design and development of CGA in the realms of nutrition delivery and the food industry. Finally, the article presents informed speculations and considerations for the future development of CGA.

Fractionation of Carlina acaulis L. Root Methanolic Extract as a Promising Path towards New Formulations against Bacillus cereus and Methicillin-Resistant Staphylococcus aureus

The root of Carlina acaulis L. has been widely used in traditional medicine for its antimicrobial properties. In this study, the fractionation of methanol extract from the root was conducted. Four fractions (A, B, C, and D) were obtained and tested against a range of bacteria and fungi. The results showed promising antibacterial activity, especially against Bacillus cereus, where the minimal inhibitory concentration (MIC) was determined to be equal to 0.08 mg/mL and 0.16 mg/mL for heptane (fraction B) and ethyl acetate (fraction C), respectively. In the case of the methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 strain, the same fractions yielded higher MIC values (2.5 and 5.0 mg/mL, respectively). This was accompanied by a lack of apparent cytotoxicity to normal human BJ foreskin fibroblasts, enterocytes derived from CaCo2 cells, and zebrafish embryos. Further analyses revealed the presence of bioactive chlorogenic acids in the fractionated extract, especially in the ethyl acetate fraction (C). These findings support the traditional use of the root from C. acaulis and pave the way for the development of new formulations for treating bacterial infections. This was further evaluated in a proof-of-concept experiment where fraction C was used in the ointment formulation, which maintained high antimicrobial activity against MRSA and displayed low toxicity towards cultured fibroblasts.

Biological Activities of Galanthus fosteri Extracts: First Demonstration of the Interaction between Chlorogenic Acid and DNA Ligase by Molecular Docking

Within the Amaryllidaceae family, the bulbous plant species Galanthus fosteri (G. fosteri) belongs to the Galanthus genus. Alkaloids with a broad variety of biological functions are typically found in the flora of this family. The G. fosteri plant's organs' antioxidant activity, antibacterial impact, and antimicrobial qualities were examined in this study. Total flavonoid contents (TFC) and total phenolic contents (TPC) of plant extracts were measured with spectrophotometric methods, and antioxidant activity was determined using the DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging technique. The HPLC method was used to determine the phenolic compounds on a component basis. The antibacterial properties of the extracts were assessed using the Kirby-Bauer disc diffusion method, and the minimum inhibitory concentration method against the pathogens Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. Additionally, combination tests were performed between the extract and antibiotics. Leaf and stem extracts demonstrated greater antioxidant qualities than bulb extracts, despite the fact that extracts of plant organs did not exhibit appreciable levels of TPC, TFC, or antioxidant qualities. According to the HPLC analysis results, it was determined that chlorogenic acid was present in all of the extracts. In fact, it was determined that only chlorogenic acid was 8.02 (mg/10 g) in G. fosteri bulb peel, which has antimicrobial and antioxidant properties. A molecular docking study has demonstrated for the first time that the antibacterial effect of chlorogenic acid might be due to DNA replication inhibition.

Deciphering the antifungal mechanism and functional components of cinnamomum cassia essential oil against Candida albicans through integration of network-based metabolomics and pharmacology, the greedy algorithm, and molecular docking

ETHNOPHARMACOLOGICAL RELEVANCE

Fungal pathogens can cause deadly invasive infections and have become a major global public health challenge. There is an urgent need to find new treatment options beyond established antifungal agents, as well as new drug targets that can be used to develop novel antifungal agents. Cinnamomum cassia is a tropical aromatic plant that has a wide range of applications in traditional Chinese medicine, especially in the treatment of bacterial and fungal infections.

AIM OF THE STUDY

The present study aimed to explore the mechanism of action and functional components of Cinnamomum cassia essential oil (CEO) against Candida albicans using an integrated strategy combining network-based metabolomics and pharmacology, the greedy algorithm and molecular docking.

MATERIALS AND METHODS

CEO was extracted using hydrodistillation and its chemical composition was identified by GC-MS. Cluster analysis was performed on the compositions of 19 other CEOs from the published literature, as well as the sample obtained in this study. The damages of C. albicans cells upon treatment with CEO was observed using a scanning electron microscope. The mechanisms of its antifungal effect at a subinhibitory concentration of 0.1 × MIC were determined using microbial metabolomics and network analysis. The functional components were studied using the greedy algorithm and molecular docking.

RESULTS

A total of 69 compounds were identified in the chemical analysis of CEO, which accounted for 90% of the sample. The major compounds were terpenoids (34.04%), aromatic compounds (4.52%), aliphatic compounds (0.9%), and others. Hierarchical cluster analysis of the compositions of 20 essential oils extracted from Cinnamomum cassia grown in different geographical locations showed a wide diversity of chemical composition with four major chemotypes. CEO showed strong antifungal activity and caused destruction of cell membranes in a concentration-dependent way. Metabolic fingerprint analysis identified 29 metabolites associated with lipid metabolism, which were mapped to 23 core targets mainly involved in fatty acid biosynthesis and metabolism. Six antifungal functional components of CEO were identified through network construction, greedy algorithm and molecular docking, including trans-cinnamaldehyde, δ-cadinol, ethylcinnamate, safrole, trans-anethole, and trans-cinnamyl acetate, which showed excellent binding with specific targets of AKR1B1, PPARG, BCHE, CYP19A1, CYP2C19, QPCT, and CYP51A1.

CONCLUSIONS

This study provides a systematic understanding of the antifungal activity of CEO and offers an integrated strategy for deciphering the potential metabolism and material foundation of complex component drugs.

The anti-inflammatory and anti-apoptotic effects of Achillea millefolium L. extracts on Clostridioides difficile ribotype 001 in human intestinal epithelial cells

BACKGROUND

Clostridioides difficile infection (CDI) is one of the most common health care-acquired infections. The dramatic increase in antimicrobial resistance of C. difficile isolates has led to growing demand to seek new alternative medicines against CDI. Achillea millefolium L. extracts exhibit strong biological activity to be considered as potential therapeutic agents. In this work, the inhibitory effects of A. millefolium, its decoction (DEC) and ethanol (ETOH) extracts, were investigated on the growth of C. difficile RT001 and its toxigenic cell-free supernatant (Tox-S) induced inflammation and apoptosis.

METHODS

Phytochemical analysis of extracts was performed by HPLC and GC analysis. The antimicrobial properties of extracts were evaluated against C. difficile RT001. Cell viability and cytotoxicity of Caco-2 and Vero cells treated with various concentrations of extracts and Tox-S were examined by MTT assay and microscopy, respectively. Anti-inflammatory and anti-apoptotic effects of extracts were assessed in Tox-S stimulated Caco-2 cells by RT-qPCR.

RESULTS

Analysis of the phytochemical profile of extracts revealed that the main component identified in both extracts was chlorogenic acid. Both extracts displayed significant antimicrobial activity against C. difficile RT001. Moreover, both extracts at concentration 50 µg/mL had no significant effect on cell viability compared to untreated cells. Pre-treatment of cells with extracts (50 µg/mL) significantly reduced the percentage of Vero cells rounding induced by Tox-S. Also, both pre-treatment and co-treatment of Tox-S stimulated Caco-2 cells with extracts significantly downregulated the gene expression level of IL-8, IL-1β, TNF-α, TGF-β, iNOS, Bax, caspase-9 and caspase-3 and upregulated the expression level of Bcl-2.

CONCLUSION

The results of the present study for the first time demonstrate the antimicrobial activity and protective effects of A. millefolium extracts on inflammatory response and apoptosis induced by Tox-S from C. difficile RT001 clinical strain in vitro. Further research is needed to evaluate the potential application of A. millefolium extracts as supplementary medicine for CDI prevention and treatment in clinical setting.

Elucidating the potential of chlorogenic acid for controlling Morganella psychrotolerans growth and histamine formation

AIM

To investigate the inhibitory impact of chlorogenic acid (CGA) on the growth of Morganella psychrotolerans and its ability to form histamine.

METHODS AND RESULTS

The antimicrobial effect of CGA on M. psychrotolerans was evaluated using the minimum inhibitory concentration (MIC) method, revealing an MIC value of 10 mg ml-1. The alkaline phosphatase (AKP) activity, cell membrane potential, and scanning electron microscopy images revealed that CGA treatment disrupted cell structure and cell membrane. Moreover, CGA treatment led to a dose-dependent decrease in crude histidine decarboxylase (HDC) activity and gene expression of histidine decarboxylase (hdc). Molecular docking analysis demonstrated that CGA interacted with HDC through hydrogen bonds. Furthermore, in situ investigation confirmed the efficacy of CGA in controlling the growth of M. psychrotolerans and significantly reducing histamine formation in raw tuna.

CONCLUSION

CGA had good activity in controlling the growth of M. psychrotolerans and histamine formation.

Impact of Chlorogenic Acid on Peripheral Blood Mononuclear Cell Proliferation, Oxidative Stress, and Inflammatory Responses in Racehorses during Exercise

Green coffee extract is currently of great interest to researchers due to its high concentration of chlorogenic acid (CGA) and its potential health benefits. CGA constitutes 6 to 10% of the dry weight of the extract and, due to its anti-inflammatory properties, is a promising natural supplement and agent with therapeutic applications. The purpose of our study was to discover the effects of CGA on peripheral blood mononuclear cell proliferation, and the production of pro- and anti-inflammatory cytokines as well as reactive oxidative species (ROS) in horses during exercise. According to the findings, CGA can affect the proliferation of T helper cells. In addition, at a dose of 50 g/mL, CGA increased the activation of CD4+FoxP3+ and CD8+FoxP3+ regulatory cells. Physical activity decreases ROS production in CD5+ monocytes, but this effect depends on the concentration of CGA, and the effect of exercise on oxidative stress was lower in CD14+ than in CD5+ cells. Regardless of CGA content, CGA significantly increased the release of the anti-inflammatory cytokine IL-10. Moreover, the production of IL-17 was greater in cells treated with 50 g/mL of CGA from beginners compared to the control and advanced groups of horses. Our findings suggest that CGA may have immune-enhancing properties. This opens new avenues of research into the mechanisms of action of CGA and possible applications in prevention and health promotion in sport animals.

UPLC-Q-TOF-MS, network analysis, and molecular docking to investigate the effect and active ingredients of tea-seed oil against bacterial pathogens

Object: This research intended to probe the antibacterial effect and pharmacodynamic substances of Tea-Seed Oil (TSO) through the use of ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF/MS) analysis, network analysis, and molecular docking. Methods: The major chemical components in the methanol-extracted fractions of TSO were subjected to UPLC-Q-TOF-MS. Network pharmacology and molecular docking techniques were integrated to investigate the core components, targets, and potential mechanisms of action through which the TSO exert their antibacterial properties. To evaluate the inhibitory effects, the minimum inhibitory concentration and diameter of the bacteriostatic circle were calculated for the potential active ingredients and their equal ratios of combinatorial components (ERCC) against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. Moreover, the quantification of the active constituents within TSO was achieved through the utilization of high-performance liquid chromatography (HPLC). Results: The methanol-extracted fractions contained a total of 47 chemical components, predominantly consisting of unsaturated fatty acids and phenolic compounds. The network pharmacology analysis and molecular docking analysis revealed that various components, including gallocatechin, gallic acid, epigallocatechin, theophylline, chlorogenic acid, puerarin, and phlorizin, have the ability to interact with critical core targets such as serine/threonine protein kinase 1 (AKT1), epidermal growth factor receptor (EGFR), a monoclonal antibody to mitogen-activated protein kinase 14 (MAPK14), HSP90AA1, and estrogen receptor 1 (ESR1). Furthermore, these components can modulate the phosphatidylinositol-3-kinase protein kinase B (PI3K-AKT), estrogen, MAPK and interleukin 17 (IL-17) signaling pathways, hereby exerting antibacterial effects. In vitro validation trials have found that seven components, namely gallocatechin, gallic acid, epigallocatechin, theophylline, chlorogenic acid, puerarin, and phloretin, displayed substantial inhibitory effects on E. coli, S. aureus, P. aeruginosa, and C. albicans, and are typically present in tea oil, with a total content ranging from 15.87∼24.91 μg·g-1. Conclusion: The outcomes of this investigation possess the possibility to expand our knowledge base concerning the utilization of TSO, furnish a theoretical framework for the exploration of antibacterial drugs and cosmetics derived from inherently occurring TSO, and establish a robust groundwork for the advancement and implementations of TOS products within clinical settings.

Chlorogenic Acid Inhibits Rahnella aquatilis KM25 Growth and Proteolytic Activity in Fish-Based Products

This work verified the antiproliferative and antiproteolytic activities of chlorogenic acid against Rahnella aquatilis KM25, a spoilage organism of raw salmon stored at 4 °C. Chlorogenic acid limited the growth of R. aqatilis KM25 in vitro at a concentration of 2.0 mg/mL. The dead (46%), viable (25%), and injured (20%) cell subpopulations were identified by flow cytometry following treatment of R. aquatilis KM25 with the examined agent. The exposure of R. aquatilis KM25 to chlorogenic acid altered its morphology. Changes in cell dimensions, mostly in length parameters from 0.778 µm to 1.09 µm, were found. The length of untreated cells ranged from 0.958 µm to 1.53 µm. The RT-qPCR experiments revealed changes in the expression of genes responsible for the proliferation and proteolytic activity of cells. Chlorogenic acid caused a significant reduction in the mRNA levels of the ftsZ, ftsA, ftsN, tolB, and M4 genes (-2.5, -1.5, -2.0, -1.5, and -1.5, respectively). In situ experiments confirmed the potential of chlorogenic acid to limit bacterial growth. A similar effect was noted in samples treated with benzoic acid, where the growth inhibition of R. aquatilis KM25 was 85-95%. Reduction of microbial R. aquatilis KM25 proliferation significantly limited total volatile base nitrogen (TVB-N) and trimethylamine (TMA-N) formation during storage, extending the shelf life of model products. The TVB-N and TMA-N parameters did not exceed the upper levels of the maximum permissible limit of acceptability. In this work, the TVB-N and TMA-N parameters were 10-25 mg/100 g and 2.5-20.5 mg/100 g, respectively; for samples with benzoic acid-supplemented marinades, the parameters TVB-N and TMA-N were 7.5-25.0 mg/100 g and 2.0-20.0 mg/100 g, respectively. Based on the results of this work, it can be concluded that chlorogenic acid can increase the safety, shelf life, and quality of fishery products.

Molecular Characterization of Some Bacillus Species from Vegetables and Evaluation of Their Antimicrobial and Antibiotic Potency

Numerous natural habitats, such as soil, air, fermented foods, and human stomachs, are home to different Bacillus strains. Some Bacillus strains have a distinctive predominance and are widely recognized among other microbial communities, as a result of their varied habitation and physiologically active metabolites. The present study collected vegetable products (potato, carrot, and tomato) from local markets in Almaty, Kazakhstan. The bacterial isolates were identified using biochemical and phylogenetic analyses after culturing. Our phylogenetic analysis revealed three Gram-positive bacterial isolates BSS11, BSS17, and BSS19 showing 99% nucleotide sequence similarities with Bacillus subtilis O-3, Bacillus subtilis Md1-42, and Bacillus subtilis Khozestan2. The crude extract was prepared from bacterial isolates to assess the antibiotic resistance potency and the antimicrobial potential against various targeted multidrug-resistant strains, including Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus group B, Streptococcus mutans, Candida albicans, Candida krusei, Pseudomonas aeruginosa, Shigella sonnei, Klebsiella pneumoniae, Salmonella enteritidis, Klebsiella aerogenes, Enterococcus hirae, Escherichia coli, Serratia marcescens, and Proteus vulgaris. This study found that the species that were identified have the ability to produce antibiotic chemicals. Additionally, the GC–MS analysis of three bacterial extracts revealed the presence of many antibiotic substances including phenol, benzoic acid, 1,2-benzenedicarboxylic acid and bis(2-methylpropyl), methoxyphenyl-oxime, and benzaldehyde. This work sheds light on the potential of Bacillus to be employed as an antimicrobial agent to target different multidrug-resistant bacterial strains. The results indicate that market vegetables may be a useful source of strains displaying a range of advantageous characteristics that can be used in the creation of biological antibiotics.

UPLC-MS Analysis, Quantification of Compounds, and Comparison of Bioactivity of Methanol Extract and Its Fractions from Qiai (Artemisia argyi Lévl. et Van.)

The Artemisia argyi Lévl. et Van. growing in the surrounding areas of Qichun County in China are called Qiai (QA). Qiai is a crop that can be used both as food and in traditional folk medicine. However, detailed qualitative and quantitative analyses of its compounds remain scarce. The process of identifying chemical structures in complex natural products can be streamlined by combining UPLC-Q-TOF/MS data with the UNIFI information management platform and its embedded Traditional Medicine Library. For the first time, 68 compounds in QA were reported by the method in this study. The method of simultaneous quantification of 14 active components in QA using UPLC-TQ-MS/MS was reported for the first time. Following a screening of the activity of QA 70% methanol total extract and its three fractions (petroleum ether, ethyl acetate, and water), it was discovered that the ethyl acetate fraction enriched with flavonoids such as eupatilin and jaceosidin had the strongest anti-inflammatory activity, while the water fraction enriched with chlorogenic acid derivatives such as 3,5-di-O-caffeoylquinic acid had the strongest antioxidant and antibacterial activity. The results provided the theoretical basis for the use of QA in the food and pharmaceutical industries.

Antibacterial Activity of Coffea robusta Leaf Extract against Foodborne Pathogens

The purpose of this study was to examine the phytochemical compounds and antibacterial activity of Coffea robusta leaf extract (RLE). The results indicated that chlorogenic acid (CGA) is a major component of RLE. The minimum inhibitory concentrations (MICs) of RLE against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, and Salmonella Typhimurium were 6.25, 12.5, 12.5, and 12.5 mg/ml, respectively. RLE effectively damages the bacterial cell membrane integrity, as indicated by the high amounts of proteins and nucleic acids released from the bacteria, and disrupts bacterial cell membrane potential and permeability, as revealed via fluorescence analysis. Cytotoxicity testing showed that RLE is slightly toxic toward HepG2 cells at high concentration but exhibited no toxicity toward Caco2 cells. The results from the present study suggest that RLE has excellent potential applicability as an antimicrobial in the food industry.

Protective effects of chlorogenic acid on inflammatory responses induced by Staphylococcus aureus and milk protein synthesis in bovine mammary epithelial cells

Staphylococcus aureus (S. aureus) is a major mastitis-causing pathogen in dairy cows. Dairy cows with mastitis suffer from a decrease in milk yield and protein content. Chlorogenic acid (CGA) is a natural product with anti-inflammatory effects. In this study, we examined the function and mechanism of CGA with regard to its anti-inflammatory effects and evaluated its protective function in milk protein synthesis in bovine mammary epithelial cells (BMECs). BMECs were cultured with and without infection by S. aureus and CGA, and extracellular inflammatory cytokines and amino acids in the medium and milk proteins were determined by ELISA. The function of IL-10RA in anti-inflammatory processes and of SF-1 in milk protein synthesis was assessed by gene silencing. The activity of mTORC1, NF-κB, and STAT5 was examined by western blot. S. aureus caused intracellular infection and upregulated TNF-α, IL-1β, IL-6, and IL-8, whereas uptake of amino acids and milk protein synthesis were suppressed. CGA mitigated the S. aureus-induced inflammatory response and milk protein synthesis in vitro and in vivo. CGA alleviated S. aureus-induced inhibition of mTORC1 and STAT5 and upregulated IL-10 and IL-10RA. In addition, SF-1 was predicted to be a transcription factor of the milk protein-encoding genes α-LA, β-LG, and CSN2. S. aureus downregulated SF-1 and CGA reversed the decline in milk protein synthesis due to SF-1 knockdown. Thus, CGA mitigates the inflammatory response that is induced by S. aureus and protects the uptake of amino acids and milk protein synthesis in BMECs.

The Biological Activity Mechanism of Chlorogenic Acid and Its Applications in Food Industry: A Review

Chlorogenic acid (CGA), also known as coffee tannic acid and 3-caffeoylquinic acid, is a water-soluble polyphenolic phenylacrylate compound produced by plants through the shikimic acid pathway during aerobic respiration. CGA is widely found in higher dicotyledonous plants, ferns, and many Chinese medicine plants, which enjoy the reputation of “plant gold.” We have summarized the biological activities of CGA, which are mainly shown as anti-oxidant, liver and kidney protection, anti-bacterial, anti-tumor, regulation of glucose metabolism and lipid metabolism, anti-inflammatory, protection of the nervous system, and action on blood vessels. We further determined the main applications of CGA in the food industry, including food additives, food storage, food composition modification, food packaging materials, functional food materials, and prebiotics. With a view to the theoretical improvement of CGA, biological activity mechanism, and subsequent development and utilization provide reference and scientific basis.

Antibacterial and Antibiofilm Activities of Chlorogenic Acid Against Yersinia enterocolitica

Nowadays, developing new and natural compounds with antibacterial activities from plants has become a promising approach to solve antibiotic resistance of pathogenic bacteria. Chlorogenic acid (CA), as a kind of phenolic acid existing in many plants, has been found to process multifunctional activities including antibacterial activity. Herein, the antibacterial and antibiofilm activities of CA against Yersinia enterocolitica (Y. enterocolitica) were tested for the first time, and its mechanism of action was investigated. It was demonstrated that CA could exert outstanding antibacterial activity against Y. enterocolitica. Biofilm susceptibility assays further indicated that CA could inhibit biofilm formation and decrease the established biofilm biomass of Y. enterocolitica. It was deduced that through binding to Y. enterocolitica, CA destroyed the cell membrane, increased the membrane permeability, and led to bacterial cell damage. In addition, the transcriptomic analysis revealed that CA could disorder many physiological pathways, mainly including the ones of antagonizing biofilms and increasing cell membrane permeability. Finally, the spiked assay showed that the growth of Y. enterocolitica in milk was significantly inhibited by CA. Taken together, CA, as an effective bactericidal effector with application potential, exerts antagonistic activity against Y. enterocolitica by mainly intervening biofilm formation and membrane permeability-related physiological pathways.

BasS/BasR Two-Component System Affects the Sensitivity of Escherichia coli to Plantaricin BM-1 by Regulating the Tricarboxylic Acid Cycle

Plantaricin BM-1, a class IIa bacteriocin produced by Lactiplantibacillus plantarum BM-1, exhibits significant antibacterial activity against many gram-positive and gram-negative bacteria. However, the mechanism underlying the action of class IIa bacteriocins against gram-negative bacteria remains to be explored. This study aimed to investigate the role of the BasS/BasR two-component system (TCS) in Escherichia coli (E. coli) K12 response to plantaricin BM-1. The IC₅₀ values for plantaricin BM-1 in E. coli K12, basS mutant (E. coli JW4073), and basR mutant (E. coli JW4074) strains were found to be 10.85, 8.94, and 7.62 mg/mL, respectively. Growth curve experiments showed that mutations in the BasS/BasR TCS led to an increase in the sensitivity of E. coli K12 to plantaricin BM-1 and that after gene complementation, the complemented mutant strain regained its original sensitivity. Proteomic analysis showed that 100 and 26 proteins were upregulated and 62 and 58 proteins were downregulated in E. coli JW4073 and E. coli JW4074, respectively. These differential proteins, which exhibited different molecular functions and participated in different molecular pathways, were mainly concentrated in the cytoplasm. More specifically, mutations in basS and basR were found to affect the synthesis and metabolism of many substances in E. coli, including many important amino acids and enzymes involved in cellular activities. In addition, 14 proteins, including 8 proteins involved in the tricarboxylic acid (TCA) cycle, were found to be downregulated in both E. coli JW4073 and E. coli JW4074. Growth curve experiments showed that the deletion of these proteins could increase the sensitivity of E. coli to plantaricin BM-1. Therefore, we speculate that TCA pathway regulation may be an important mechanism by which the BasS/BasR TCS regulates the sensitivity of E. coli to plantaricin BM-1. This finding will facilitate the determination of the mechanism underlying the action of class IIa bacteriocins against gram-negative bacteria.

Phenolic-Rich Plant Extracts With Antimicrobial Activity: An Alternative to Food Preservatives and Biocides?

In recent years, the search for natural plant-based antimicrobial compounds as alternatives to some synthetic food preservatives or biocides has been stimulated by sanitary, environmental, regulatory, and marketing concerns. In this context, besides their established antioxidant activity, the antimicrobial activity of many plant phenolics deserved increased attention. Indeed, industries processing agricultural plants generate considerable quantities of phenolic-rich products and by-products, which could be valuable natural sources of natural antimicrobial molecules. Plant extracts containing volatile (e.g., essential oils) and non-volatile antimicrobial molecules can be distinguished. Plant essential oils are outside the scope of this review. This review will thus provide an overview of current knowledge regarding the promises and the limits of phenolic-rich plant extracts for food preservation and biofilm control on food-contacting surfaces. After a presentation of the major groups of antimicrobial plant phenolics, of their antimicrobial activity spectrum, and of the diversity of their mechanisms of action, their most promising sources will be reviewed. Since antimicrobial activity reduction often observed when comparing in vitro and in situ activities of plant phenolics has often been reported as a limit for their application, the effects of the composition and the microstructure of the matrices in which unwanted microorganisms are present (e.g., food and/or microbial biofilms) on their activity will be discussed. Then, the different strategies of delivery of antimicrobial phenolics to promote their activity in such matrices, such as their encapsulation or their association with edible coatings or food packaging materials are presented. The possibilities offered by encapsulation or association with polymers of packaging materials or coatings to increase the stability and ease of use of plant phenolics before their application, as well as to get systems for their controlled release are presented and discussed. Finally, the necessity to consider phenolic-rich antimicrobial plant extracts in combination with other factors consistently with hurdle technology principles will be discussed. For instance, several authors recently suggested that natural phenolic-rich extracts could not only extend the shelf-life of foods by controlling bacterial contamination, but could also coexist with probiotic lactic acid bacteria in food systems to provide enhanced health benefits to human.

Evaluation of In Vitro Wound-Healing Potential, Antioxidant Capacity, and Antimicrobial Activity of Stellaria media (L.) Vill

The healing of skin wounds remains an important concern in medicine, especially in chronic wounds caused by various diseases such as diabetes. Using herbs or herbal products to heal skin wounds is a therapeutic challenge for traditional medicine. In this context, the main aim of our work was to highlight the in vitro healing potential of Stellaria media (L.) Vill. (SM) extract using the scratch assay on normal human dermal fibroblasts (NHDF). The ability to stimulate cell migration and proliferation under the influence of different concentrations of SM extract (range between 12.5 and 200 µg/mL) was determined compared to the control (untreated in vitro-simulated wound) and positive control (allantoin 50 µg/mL). Our results showed that the concentration of 100 µg/mL SM extract applied on the simulated wound recorded the strongest and fastest (24 h) migration (with wound closure) and proliferation of NHDF compared with the control. In addition, the SM extract was characterized in terms of bioactive compounds (total phenols and flavonoids content), antioxidant capacity (FRAP (The Ferric-Reducing Antioxidant Power) assay and electrochemical method), and antimicrobial activity. The results show that the SM extract contains a considerable amount of polyphenols (17.19 ± 1.32 mg GAE/g dw and 7.28 ± 1.18 mg QE/g dw for total phenol and flavonoid content, respectively) with antioxidant capacity. Antimicrobial activity against Gram-positive bacteria (S. aureus) is higher than E. coli at a dose of 15 µg/mL. This study showed that Stellaria media is a source of polyphenols compounds with antioxidant capacity, and for the first time, its wound healing potential was emphasized.

Evaluation of the Membrane Damage Mechanism of Chlorogenic Acid against Yersinia enterocolitica and Enterobacter sakazakii and Its Application in the Preservation of Raw Pork and Skim Milk

Plant-derived antimicrobial agents have adequate antimicrobial effects on food-borne pathogens, which can be used as food preservatives. The purpose of this study was to evaluate the antibacterial mechanism of chlorogenic acid (CA) against Yersinia enterocolitica and Enterobacter sakazakii. The minimum inhibitory concentration (MIC) of CA was determined by employing the broth microdilution method. Then, the cell function and morphological changes of Y. enterocolitica and E. sakazakii treated with CA were characterized. Finally, the growth inhibition models of Y. enterocolitica in raw pork and E. sakazakii in skim milk were constructed through the response surface methodology. The results demonstrated that CA has a satisfactory inhibitory effect against Y. enterocolitica and E. sakazakii with a MIC of 2.5 mg/mL. In addition, CA inhibited the growth of Y. enterocolitica and E. sakazakii via cell membrane damage, such as depolarization of the cell membrane, reduction in intracellular adenosine triphosphate (ATP) and pH levels, and destruction of cell morphology. Moreover, CA reduced two log cycles of Y. enterocolitica in raw pork and E. sakazakii in skim milk at a certain temperature. According to the corresponding findings, CA has the potential to be developed as an effective preservative to control Y. enterocolitica and E. sakazakii-associated foodborne diseases.

Evaluation of a strawberry fermented beverage with potential health benefits

Background

Functional fermented beverages are popular worldwide due to their potential to promote health. Starter culture is the main determinant of the final quality and flavor of fermented beverages. The co-cultivation of lactic acid bacteria (LAB) and yeast makes a significant contribution to the safe flavor of fermented beverages. However, the research on the potential of antioxidant, antimicrobial, and anti-biofilm formation of strawberry fermented beverage obtained by combining the LAB and yeast as starter cultures has not been well explored.

Methods

In this study, LAB and yeast were combined as starter culture to obtain strawberry fermented beverage. Fourier transform infrared (FTIR ) spectroscopy was used for the qualitative analysis of the fresh strawberry juice and fermented beverage. From the changes in antioxidant content, free radical scavenging ability, total superoxide dismutase (T-SOD) activity and total antioxidant capacity (T-AOC) to evaluate the antioxidant capacity of fermented beverage in vitro. The antibacterial ability was tested by the Oxford cup method. The biofilms of Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 6538 under fermented beverages treatment was observed by Fluorescence microscope. In addition, sensory analysis was conducted in this study.

Results

In this study, the absorption peaks of Fourier transform infrared between 1,542 cm^-1 and 976 cm^-1, suggest the existence of organic acids, sugars and ethanol. The total phenols and total flavonoids content decreased by 91.1% and 97.5%, respectively. T-SOD activity increased by 33.33%.The scavenging ability of fermented beverage on superoxide anion free radicals was enhanced, and the scavenging ability on DPPH free radicals, hydroxyl free radicals, and ABTS free radicals was weakened. However, the T-AOC increased from 4.15 ± 0.81 to 8.43 ± 0.27 U/mL. Fermented beverage shows antibacterial activity against four pathogens. The minimum inhibitory concentration (MIC) values of Escherichia coli ATCC 25922 and Staphylococcus aureus ATCC 6538 were 0.05 mL/mL and 0.025 mL/mL, respectively, and the minimum bactericidal concentration (MBC) were both 0.2 mL/mL. It was observed by fluorescence microscope that the green fluorescence area of the two biofilms is greatly reduced after being treated with fermented beverage. Sensory analysis results show that the average scores of fermented beverage in color, appearance and taste were increased. The overall impression and flavor were decreased.

Conclusion

These results demonstrated that strawberry fermented beverage has potential benefits such as an antioxidant, antibacterial, and anti-biofilm formation, providing the potential for the fermented beverage to become promising candidates for natural antioxidants, antibacterial agents and anti-biofilm agents.