Structure-function relationships of the antibacterial activity of phenolic acids and their metabolism by lactic acid bacteria

The synergistic potential of orange peel extract: A comprehensive investigation into its phenolic composition, antioxidant, antimicrobial, and functional fortification properties in yogurt

The study explores the potential of orange peel extract (OPE) as a versatile natural resource, focusing on its phenolic composition, antioxidant, and antibacterial properties, as well as its application in fortifying yogurt. Analysis revealed significant concentrations of phenolic compounds in OPE. OPE exhibited notable antibacterial efficacy against pathogenic bacteria, particularly marine Escherichia coli, with synergistic effects observed when combined with Amikacin. Incorporating OPE into yogurt led to changes in chemical composition, enhancing total proteins, fat, and ash content. Fortified yogurt showed increased antioxidant activity and potential anti-cancer properties against HCT116 cell lines. In conclusion, OPE emerges as a rich source of bioactive compounds with diverse applications, from its antioxidant and antibacterial properties to its potential in fortifying functional foods like yogurt. This comprehensive exploration provides valuable insights into the multifaceted benefits of OPE, paving the way for its utilization in various industries and health-related applications.

Exploiting the beneficial effects of Salvia officinalis L. extracts in human health and assessing their activity as potent functional regulators of food microbiota

Salvia officinalis L. has attracted scientific and industrial interest due to its pharmacological properties. However, its detailed phytochemical profile and its correlation with beneficial effects in the human microbiome and oxidative stress remained elusive. To unveil this, S. officinalis was collected from the region of Epirus and its molecular identity was verified with DNA barcoding. Phytochemical profile for both aqueous and ethanol-based extracts was determined by high-pressure liquid chromatography-tandem mass spectrometry and 103 phytochemicals were determined. The effect of S. officinalis extracts as functional regulators of food microbiota by stimulating the growth of Lacticaseibacillus rhamnosus strains and by suppressing evolution of pathogenic bacteria was verified. Furthermore, we recorded that both extracts exhibited a significant cellular protection against H2O2-induced DNA damage. Finally, both extracts exhibited strong inhibitory effect towards LDL oxidation. This study provides a comprehensive characterization of S. officinalis on its phytochemical components as also its potential impact in human microbiome and oxidative stress.

Antimicrobial Effect of Lippia citriodora Extract in Combination with Gallic Acid or Octyl Gallate on Bacteria from Meat

Chicken meat and its derivatives are easily alterable. They are a nutritionally healthy food, and their consumption has seen a remarkable increase worldwide in recent years. At the same time, consumer demand for the use of natural products to control microbial growth is increasing. In this context, the antimicrobial capacity of a commercial extract of the lemon verbena (Lippia citriodora) plant, (LCE) was tested in binary combination with gallic acid or octyl gallate against two strains of lactic acid bacteria (LAB) of meat origin: Carnobacterium divergens ATCC 35677 and Leuconostoc carnosum ATCC 49367. First, the antimicrobial potential was evaluated by the checkerboard microdilution method at the optimal growth temperature of each and at 4 °C, pH 5.7 and 6.7, in culture medium. Octyl gallate was the most effective antimicrobial against the two bacteria under all study conditions. At 4 °C, the combination of LCE with octyl gallate had a similar antimicrobial effect on the two LAB, being bactericidal at pH 6.7. In chicken breast, this effective combination was tested in normal or modified atmosphere and refrigerated (4-8 °C) for 9 days. LCE + OG in modified atmosphere reduced the different microbial groups studied, including the lactic acid bacteria as the main microorganisms responsible for the spoilage of fresh meat. Further research could pave the way for the development of novel strategies contributing to the technological stability, security, and functional properties of chicken meat.

Discovery of a novel class of rosmarinic acid derivatives as antibacterial agents: Synthesis, structure-activity relationship and mechanism of action

Twenty-seven rosmarinic acid derivatives were synthesized, among which compound RA-N8 exhibited the most potent antibacterial ability. The minimum inhibition concentration of RA-N8 against both S. aureus (ATCC 29213) and MRSA (ATCC BAA41 and ATCC 43300) was found to be 6 μg/mL, and RA-N8 killed E. coli (ATCC 25922) at 3 μg/mL in the presence of polymyxin B nonapeptide (PMBN) which increased the permeability of E. coli. RA-N8 exhibited a weak hemolytic effect at the minimum inhibitory concentration. SYTOX Green assay, SEM, and LIVE/DEAD fluorescence staining assay proved that the mode of action of RA-N8 is targeting bacterial cell membranes. Furthermore, no resistance in wildtype S. aureus developed after incubation with RA-N8 for 20 passages. Cytotoxicity studies further demonstrated that RA-N8 is non-toxic to the human normal cell line (HFF1). RA-N8 also exerted potent inhibitory ability against biofilm formation of S. aureus and even collapsed the shaped biofilm.

Plant-derived bioactive compounds for the inhibition of biofilm formation: a comprehensive review

Biofilm formation is a widespread phenomenon that impacts different fields, including the food industry, agriculture, health care and the environment. Accordingly, there is a serious need for new methods of managing the problem of biofilm formation. Natural products have historically been a rich source of varied compounds with a wide variety of biological functions, including antibiofilm agents. In this review, we critically highlight and discuss the recent progress in understanding the antibiofilm effects of several bioactive compounds isolated from different plants, and in elucidating the underlying mechanisms of action and the factors influencing their adhesion. The literature shows that bioactive compounds have promising antibiofilm potential against both Gram-negative and Gram-positive bacterial and fungal strains, via several mechanisms of action, such as suppressing the formation of the polymer matrix, limiting O2 consumption, inhibiting microbial DNA replication, decreasing hydrophobicity of cell surfaces and blocking the quorum sensing network. This antibiofilm activity is influenced by several environmental factors, such as nutritional cues, pH values, O2 availability and temperature. This review demonstrates that several bioactive compounds could mitigate the problem of biofilm production. However, toxicological assessment and pharmacokinetic investigations of these molecules are strongly required to validate their safety.

Fermentation of Orange Peels by Lactic Acid Bacteria: Impact on Phenolic Composition and Antioxidant Activity

Orange processing generates peel by-products rich in phenolic compounds, particularly flavanones like hesperidin and narirutin, offering potential health benefits. Utilizing these by-products is of significant interest in supporting Spain's circular bioeconomy. Therefore, the aim of this study was to investigate the fermentation of orange peels by different lactic acid bacteria (LAB) strains and its impact on phenolic composition and antioxidant activity. Three different LAB strains, two Lactiplantibacillus plantarum, and one Levilactobacillus brevis were utilized. The phenolic compounds were measured by HPLC-ESI-TOF-MS, and antioxidant activity was assessed using DPPH and ABTS methods. The growth of the LAB strains varied, showing initial increases followed by gradual declines, with strain-specific patterns observed. Medium acidification occurred during fermentation. A phenolic analysis revealed an 11% increase in phenolic acids in peels fermented by La. plantarum CECT 9567-C4 after 24 h, attributed to glycosylation by LAB enzymes. The flavonoid content exhibited diverse trends, with Le. brevis showing an 8% increase. The antioxidant assays demonstrated strain- and time-dependent variations. Positive correlations were found between antioxidant activity and total phenolic compounds. The results underscore the importance of bacterial selection and fermentation time for tailored phenolic composition and antioxidant activity in orange peel extracts. LAB fermentation, particularly with La. plantarum CECT 9567 and Le. brevis, holds promise for enhancing the recovery of phenolic compounds and augmenting antioxidant activity in orange peels, suggesting potential applications in food and beverage processing.

Visible-light photoactivated proanthocyanidin and kappa-carrageenan coating with anti-adhesive properties against clinically relevant bacteria

The increase of bacterial resistance to antibiotics is a growing concern worldwide and the search for new therapies could cost billions of dollars and countless lives. Inert surfaces are major sources of contamination due to easier adhesion and formation of bacterial biofilms, hindering the disinfection process. Therefore, the objective of this study was to develop a photoactivatable and anti-adhesive kappa-carrageenan coating using proanthocyanidin as a photosensitizer. The complete reduction (>5-log10 CFU/cm3) of culturable cells of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa pathogens was achieved after 30 min of exposure to visible light (420 nm; 30 mW/cm2) with 5 % (w/v) of the photosensitizer. Cell membrane damage was confirmed by measuring potassium leakage, epifluorescence microscopy and bacterial motility analysis. Overall, visible light irradiation on coated solid surfaces mediated by proanthocyanidin showed no cytotoxicity and inactivated clinically important pathogens through the generation of reactive oxygen species, inhibiting bacterial initial adhesion. The developed coating is a promising alternative for a wide range of applications related to surface disinfection and food biopreservation.

Natural polyphenols for drug delivery and tissue engineering construction: A review

Polyphenols, natural compounds rich in phenolic structures, are gaining prominence due to their antioxidant, anti-inflammatory, antibacterial, and anticancer properties, making them valuable in biomedical applications. Through covalent and noncovalent interactions, polyphenols can bind to biomaterials, enhancing their performance and compensating for their shortcomings. Such polyphenol-based biomaterials not only increase the efficacy of polyphenols but also improve drug stability, control release kinetics, and boost the therapeutic effects of drugs. They offer the potential for targeted drug delivery, reducing off-target impacts and enhancing therapeutic outcomes. In tissue engineering, polyphenols promote cell adhesion, proliferation, and differentiation, thus aiding in the formation of functional tissues. Additionally, they offer excellent biocompatibility and mechanical strength, essential in designing scaffolds. This review explores the significant roles of polyphenols in tissue engineering and drug delivery, emphasizing their potential in advancing biomedical research and healthcare.

Optimization of Clostridium beijerinckii semi-solid fermentation of rape straw to produce butyric acid by genome analysis

Butyric acid is a volatile saturated monocarboxylic acid, which is widely used in the chemical, food, pharmaceutical, energy, and animal feed industries. This study focuses on producing butyric acid from pre-treated rape straw using simultaneous enzymatic hydrolysis semi-solid fermentation (SEHSF). Clostridium beijerinckii BRM001 screened from pit mud of Chinese nongxiangxing baijiu was used. The genome of C. beijerinckii BRM001 was sequenced and annotated. Using rape straw as the sole carbon source, fermentation optimization was carried out based on the genomic analysis of BRM001. The optimized butyric acid yield was as high as 13.86 ± 0.77 g/L, which was 2.1 times higher than that of the initial screening. Furthermore, under optimal conditions, non-sterile SEHSF was carried out, and the yield of butyric acid was 13.42 ± 0.83 g/L in a 2.5-L fermentor. This study provides a new approach for butyric acid production which eliminates the need for detoxification of straw hydrolysate and makes full use of the value of fermentation waste residue without secondary pollution, making the whole process greener and more economical, which has a certain industrial potential.

Comparative polyphenolic profiling of five ethnomedicinal plants and their applicative potential in the treatment of type 2 diabetes

ETHNOPHARMACOLOGICAL RELEVANCE

The medicinal plants Salvia officinalis, Trifolium pratense, Agrimonia eupatoria, Cichorium intybus and Vinca minor are traditionally used for the prevention and treatment of numerous diseases, including diabetes.

AIM OF THE STUDY

Type 2 diabetes (T2D) is one of the most common diseases nowadays, often accompanied by oxidative stress and microbial infections. The aim of our work was to examine the antidiabetic, antioxidant, and antimicrobial properties of ethanol extracts of five medicinal plants for the purpose of their possible use in the treatment of T2D.

MATERIALS AND METHODS

The polyphenolic profile of the plant extracts was analyzed by Ultra-High Performance Liquid Chromatography with a diode array detector configured with a triple quadrupole mass spectrometer (UHPLC/DAD/(-)HESI-MS2). In vitro antidiabetic activity of extracts was determined by measuring the percentage of α-amylase and α-glucosidase inhibition. The antioxidant activity of the extract was determined by different spectrophotometric methods, while the antimicrobial activity was determined by agar dilution and disc diffusion methods.

RESULTS

A. eupatoria extract contains the highest percentage of flavonoids (94%, with isoquercetin, vitexin, and rutin as the most abundant) in relation to the concentration of total phenolic compounds and exhibits excellent antidiabetic, antioxidant, and antimicrobial activity. S. officinalis extract contains 60% flavonoids (predominately cirsimaritin and epigallocatechin gallate) and 40% phenolic acids (with rosmarinic acid being the most abundant from this group) and exhibits weak antidiabetic activity, significant antioxidant activity, and excellent antibacterial activity. A 45% percentage of flavonoids (with isoquercetin as the most abundant one) and 55% of phenolic acids (with ferulic acid as the most abundant) were measured in the extract of T. pratense, which had excellent antidiabetic activity but weaker antioxidant and antimicrobial activity. A similar percentage of flavonoids (52%, with epigallocatechin gallate in the highest concentration) and phenolic acids (48%, with chlorogenic acid as the most abundant) was measured in the extract of C. intybus which showed moderate antidiabetic, antioxidant, and antimicrobial properties. The extract of V. minor was the richest in phenolic acids (80%, with the most abundant chlorogenic acid), which resulted in weaker antidiabetic and antioxidant activities (except for Fe2+ chelating ability) and antimicrobial activity.

CONCLUSION

The results indicate that specific phenolic compounds are responsible for the different biological activities of the plant extracts. Among the investigated plants, the extract of A. eupatoria has the greatest potential for applications in the treatment of T2D.

Phenolic acid-chitosan derivatives: An effective strategy to cope with food preservation problems

Chitosan, a cost-effective and eco-friendly natural polymeric material, possesses excellent film-forming properties. However, it has low solubility and biological activity, which hinders its widespread applications. To overcome these limitations, researchers have developed phenolic acid-chitosan derivatives that greatly enhance the mechanical, antibacterial and antioxidant properties of chitosan, expanding its potential application, particularly in food preservation. This review aims to provide an in-depth understanding of the structure and biological activity of chitosan and phenolic acid, as well as various synthetic techniques employed in their modification. Phenolic acid-chitosan derivatives exhibit improved physicochemical properties, such as enhanced water solubility, thermal stability, rheological properties, and crystallinity, through grafting techniques. Moreover, these derivatives demonstrate significantly enhanced antibacterial and antioxidant activities. Through graft modification, phenolic acid-chitosan derivatives offer promising applications in food preservation for diverse food products, including fruits, vegetables, meat, and aquatic products. Their ability to improve the preservation and quality of these food items makes them an appealing option for the food industry. This review intends to provide a deeper understanding of phenolic acid-chitosan derivatives by delving into their synthetic technology, characterization, and application in the realm of food preservation.

Bio-based active packaging: Gallic acid modified agarose coatings in grass carp (Ctenopharyngodon idellus) preservation

Antioxidant and antimicrobial agarose coatings were developed by grafting gallic acid through the carbodiimide coupling method. Structural characterization revealed that the carboxyl group of gallic acid was successfully grafted onto the C6-OH of D-galactose in agarose, with the highest observed grafting ratio being 13.73 %. The grafting of gallic acid significantly increased the antioxidant and bacteriostatic activities of the agarose. As the grafting ratio of gallic acid-modified agarose (GaAg) increased from 0 to 13.73 %, the scavenging ratio of DPPH and the inhibition ratio of β-carotene bleaching were observed to increase from 0 % to 65.92 % and 6.89 % to 73.46 %, respectively. GaAg exhibited up to 100 % inhibition of Escherichia coli and Staphylococcus aureus. The physicochemical properties of gel strength, viscosity, gelling temperature and melting temperature decreased to 971.3 g/cm2, 17.9 mPa·s, 31.7 °C and 84.1 °C, respectively. The gel contact angle was increased from 22.1° to 73.6°. Fish preservation tests have demonstrated that it effectively inhibited bacterial growth, prevented fat oxidation, blocked light, reduced moisture loss, and enhanced the overall quality of grass carp (Ctenopharyngodon idellus) fillets during refrigeration, which was more effective than native agarose in extending the shelf life of fish. Therefore, GaAg holds promise as an aquatic product preservative.

Anti-Staphylococcal, Anti-Candida, and Free-Radical Scavenging Potential of Soil Fungal Metabolites: A Study Supported by Phenolic Characterization and Molecular Docking Analysis

Staphylococcus and Candida are recognized as causative agents in numerous diseases, and the rise of multidrug-resistant strains emphasizes the need to explore natural sources, such as fungi, for effective antimicrobial agents. This study aims to assess the in vitro anti-staphylococcal and anti-candidal potential of ethyl acetate extracts from various soil-derived fungal isolates. The investigation includes isolating and identifying fungal strains as well as determining their antioxidative activities, characterizing their phenolic substances through HPLC analysis, and conducting in silico molecular docking assessments of the phenolics' binding affinities to the target proteins, Staphylococcus aureus tyrosyl-tRNA synthetase and Candida albicans secreted aspartic protease 2. Out of nine fungal species tested, two highly potent isolates were identified through ITS ribosomal gene sequencing: Aspergillus terreus AUMC 15447 and A. nidulans AUMC 15444. Results indicated that A. terreus AUMC 15447 and A. nidulans AUMC 15444 extracts effectively inhibited S. aureus (concentration range: 25-0.39 mg/mL), with the A. nidulans AUMC 15444 extract demonstrating significant suppression of Candida spp. (concentration range: 3.125-0.39 mg/mL). The A. terreus AUMC 15447 extract exhibited an IC50 of 0.47 mg/mL toward DPPH radical-scavenging activity. HPLC analysis of the fungal extracts, employing 18 standards, revealed varying degrees of detected phenolics in terms of their presence and quantities. Docking investigations highlighted rutin as a potent inhibitor, showing high affinity (-16.43 kcal/mol and -12.35 kcal/mol) for S. aureus tyrosyl-tRNA synthetase and C. albicans secreted aspartic protease 2, respectively. The findings suggest that fungal metabolites, particularly phenolics, hold significant promise for the development of safe medications to combat pathogenic infections.

Span 60/Cholesterol Niosomal Formulation as a Suitable Vehicle for Gallic Acid Delivery with Potent In Vitro Antibacterial, Antimelanoma, and Anti-Tyrosinase Activity

Natural compounds such as gallic acid (GA) have attracted more attention in cosmetic and pharmaceutical skin care products. However, the low solubility and poor stability of GA have limited its application. This study aimed to synthesize and characterize the GA niosomal dispersion (GAN) and investigate the potential of an optimal formulation as a skin drug delivery system for GA. For this purpose, GAN formulations were synthesized using the thin layer evaporation method with different molar ratios of Tween 60/Span 60, along with a constant molar ratio of polyethylene glycol 4000 (PEG-4000) and cholesterol in a methanol and chloroform solvent (1:4 v/v). The physicochemical properties of nanosystems in terms of size, zeta potential, drug entrapment, drug release, morphology, and system-drug interaction were characterized using different methods. In addition, in vitro cytotoxicity, anti-tyrosinase activity, and antibacterial activity were evaluated by MTT assay, the spectrophotometric method, and micro-well dilution assay. All formulations revealed a size of 80-276 nm, polydispersity index (PDI) values below 0.35, and zeta potential values below-9.7 mV. F2 was selected as the optimal formulation due to its smaller size and high stability. The optimal formulation of GAN (F2) was as follows: a 1:1 molar ratio of Span 60 to cholesterol and 1.5 mM GA. The release of the F2 drug showed a biphasic pattern, which was fast in the first 12 h until 58% was released. Our results showed the high antibacterial activity of GAN against Escherichia coli and Pseudomonas aeruginosa. The MTT assay showed that GA encapsulation increased its effect on B6F10 cancer cells. The F2 formulation exhibited potent anti-tyrosinase activity and inhibited melanin synthesis. These findings suggest that it can be used in dermatological skin care products in the cosmetic and pharmaceutical industries due to its significant antibacterial, anti-melanoma, and anti-tyrosinase activity.

Shaping Future Foods through Fermentation of Side Streams: Microbial, Chemical, and Physical Characteristics of Fermented Blends from Sunflower Seed Press Cake and Cheese Whey

The current food system suffers from the inefficient use of resources, including the generation of side streams of low economic value that still contain nutritional components. One potential approach to reach a more sustainable food system is to reintroduce such side streams into a circular value chain and valorise them in novel food products, preferably in an unrefined or minimally refined manner. Blending side streams from different industries might be a suitable way to improve the nutritional value of the final matrix. In this study, sunflower seed press cake and cheese whey were combined to obtain matrices containing valuable proteins, structuring polysaccharides, as well as lactose and minerals facilitating fermentation with three different co-cultures of lactic acid bacteria and yeasts. Fermentation for 48 h at 26 °C decreased the pH from ~6.3 to ~4.7 and enhanced the storage stability of the blends with no effect on their rheological properties and microstructure. This research demonstrates the potential of fermentation as a mean to stabilise side stream blends while only minimally affecting their physical appearance.

Gut microbial metabolites of dietary polyphenols and their potential role in human health and diseases

Polyphenols contribute as one of the largest groups of compounds among all the phytochemicals. Common sources of dietary polyphenols are vegetables, fruits, berries, cereals, whole grains, etc. Owing to their original form, they are difficult to get absorbed. Dietary polyphenols after undergoing gut microbial metabolism form bioaccessible and effective metabolites. Polyphenols and derived metabolites are all together a diversified group of compounds exhibiting pharmacological activities against cardiovascular, cancer, oxidative stress, inflammatory, and bacterial diseases. The formed metabolites are sometimes even more bioavailable and efficacious than the parent polyphenols. Studies on gut microbial metabolism of dietary polyphenols have introduced new approach for the use of polyphenol-rich food in the form of supplementary diet. This review provides insights on various aspects including classification of polyphenols, gut microbiota-mediated metabolism of polyphenols, chemistry of polyphenol metabolism, and pharmacological actions of gut microbial metabolites of polyphenols. It also suggests the use of polyphenols from marine source for the microbial metabolism studies. Till date, gut microbial metabolism of polyphenols from terrestrial sources is extensively studied as compared to marine polyphenols. Marine ecosystem is a profound but partially explored source of phytoconstituents. Among them, edible seaweeds contain high concentration of polyphenols, especially phlorotannins. Hence, microbial metabolism studies of seaweeds can unravel the pharmacological potential of marine polyphenol-derived metabolites.

Physiological and genomic characterization of Lactiplantibacillus plantarum isolated from Indri indri in Madagascar

AIMS

Indri indri is a lemur of Madagascar which is critically endangered. The analysis of the microbial ecology of the intestine offers tools to improve conservation efforts. This study aimed to achieve a functional genomic analysis of three Lactiplantibacillus plantarum isolates from indris.

METHODS AND RESULTS

Samples were obtained from 18 indri; 3 isolates of Lp. plantarum were obtained from two individuals. The three isolates were closely related to each other, with <10 single nucleotide polymorphisms, suggesting that the two individuals shared diet-associated microbes. The genomes of the three isolates were compared to 96 reference strains of Lp. plantarum. The three isolates of Lp. plantarum were not phenotypically resistant to antibiotics but shared all 17 genes related to antimicrobial resistance that are part of the core genome of Lp. plantarum. The genomes of the three indri isolates of Lp. plantarum also encoded for the 6 core genome genes coding for enzymes related to metabolism of hydroxybenzoic and hydroxycinnamic acids. The phenotype for metabolism of hydroxycinnamic acids by indri isolates of Lp. plantarum matched the genotype.

CONCLUSIONS

Multiple antimicrobial resistance genes and gene coding for metabolism of phenolic compounds were identified in the genomes of the indri isolates, suggesting that Lp. plantarum maintains antimicrobial resistance in defense of antimicrobial plant secondary pathogens and that their metabolism by intestinal bacteria aids digestion of plant material by primate hosts.

Ultrasound-assisted fermentation of ginkgo kernel juice by Lactiplantibacillus plantarum: Microbial response and juice composition development

This study is aimed to explore the feasibility of ultrasound on enhancing the fermentation properties of ginkgo kernel juice by Lactiplantibacillus plantarum Y2. Specifically, ultrasound at 20 kHz and different intensities (mild ultrasound intensity-84.42 W/L, moderate ultrasound intensity-115.50 W/L, high ultrasound intensity-173.88 W/L) with a pulse mode were applied to facilitate the fermentation process. The number of viable cells of Lactiplantibacillus plantarum Y2 increased by 5.06, 5.05 and 2.19% in the sonicated groups at 173.88, 115.50 and 84.42 W/L, compared with the non-sonicated juice after 24-h fermentation. Furthermore, mild intensity ultrasonication improved the permeability of the cell membrane, which is beneficial for the metabolism of phenolics, amino acids and organic acids. Ultrasonication increased in-vitro antioxidant activity of fermented ginkgo kernel juice by promoting the metabolism of phenolic acids, such as ferulic acid, chlorogenic and caffeic acids. At the end of fermentation, the sonicated group at 84.42 W/L has the maximum consumptions of total sugars and proteins (increased by 12.52 and 18.73%). Moreover, the reduction rate of the poison material 4'-O-methylpyridoxine (MPN) in ginkgo kernel juice increased by more than 16.40% with ultrasound treatment at 173.88 W/L after the fermentation for 48 h. Overall, ultrasound can improve the metabolizations of Lactobacillus plantarum and reduce the toxic substances, which promoted the nutritional value and flavors of ginkgo kernel juice.

Methane reduction by quercetin, tannic and salicylic acids: influence of molecular structures on methane formation and fermentation in vitro

Plant secondary metabolites (PSMs) can potentially reduce ruminal methane formation. However, related to differences in their molecular structures, it is not yet clear what causes an anti-methanogenic effect. In an in vitro system simulating rumen fermentation, we investigated the impact of eight compounds with distinct chemical characteristics (gallic and salicylic acids, tannic acid, catechin, epicatechin, quercetin, rutin, and salicin) when added to a basal feed (maize silage) at a concentration of 12% of the feed dry matter. After 48 h of incubation in buffered rumen fluid, methane production was significantly lowered by quercetin (43%), tannic acid (39%) and salicylic acid (34%) compared to the control (maize silage alone) and without changes in total volatile fatty acid production during fermentation. No other PSM reduced methane formation as compared to control but induced significant differences on total volatile fatty acid production. The observed differences were related to lipophilicity, the presence of double bond and carbonyl group, sugar moieties, and polymerization of the compounds. Our results indicate the importance of distinct molecular structures of PSMs and chemical characteristics for methane lowering properties and volatile fatty acid formation. Further systematic screening studies to establish the structure-function relationship between PSMs and methane reduction are warranted.

New Strategies for Biocontrol of Bacterial Toxins and Virulence: Focusing on Quorum-Sensing Interference and Biofilm Inhibition

The overuse of antibiotics and the emergence of multiple-antibiotic-resistant pathogens are becoming a serious threat to health security and the economy. Reducing antimicrobial resistance requires replacing antibiotic consumption with more biocontrol strategies to improve the immunity of animals and humans. Probiotics and medicinal plants have been used as alternative treatments or preventative therapies for a variety of diseases caused by bacterial infections. Therefore, we reviewed some of the anti-virulence and bacterial toxin-inhibiting strategies that are currently being developed; this review covers strategies focused on quenching pathogen quorum sensing (QS) systems, the disruption of biofilm formation and bacterial toxin neutralization. It highlights the probable mechanism of action for probiotics and medicinal plants. Although further research is needed before a definitive statement can be made on the efficacy of any of these interventions, the current literature offers new hope and a new tool in the arsenal in the fight against bacterial virulence factors and bacterial toxins.

Allelopathic Activity of the Invasive Plant Polygonum chinense Linn. and Its Allelopathic Substances

Polygonum chinense Linn., belonging to the Polygonaceae family, is distributed mostly in northern temperate climates. This species is a high-risk invasive plant and is thought to possess allelopathic potential. This study aimed to isolate and identify the allelopathic substances from P. chinense. Aqueous methanol extracts of P. chinense significantly inhibited the growth of alfalfa and Italian ryegrass seedlings in a species- and concentration-dependent manner. Activity-guided fractionation led to the isolation of two active compounds: dehydrovomifoliol and loliolide. A cress bioassay was used to determine the biological activity of dehydrovomifoliol, and cress, alfalfa, and Italian ryegrass were used to determine loliolide. Dehydrovomifoliol significantly suppressed the seedling growth of cress at the concentration of 1 mM, and the concentrations necessary for 50% growth inhibition (I50 values) of the roots and shoots were 1.2 and 2 mM, respectively. Loliolide significantly suppressed the shoot growth of cress, alfalfa, and Italian ryegrass at the concentration of 1 mM, and the concentrations necessary for I50 values of the shoots and roots were 0.15 to 2.33 and 0.33 to 2.23 mM, respectively. The findings of our study suggest the extracts of P. chinense might have growth-inhibitory potential and that dehydrovomifoliol and loliolide might contribute as allelopathic agents.

An Overview of the Use and Applications of Limosilactobacillus fermentum in Broiler Chickens

The implementation of government regulations on antibiotic use, along with the public's concern for drug resistance, has strengthened interest in developing alternatives not only aimed at preserving animal production but also at reducing the effects of pathogenic infections. Probiotics, in particular, are considered microorganisms that induce health benefits in the host after consumption of adequate amounts; they have been established as a potential strategy for improving growth, especially by stimulating intestinal homeostasis. Probiotics are commonly associated with lactic acid bacteria, and Limosilactobacillus fermentum is a well-studied species recognized for its favorable characteristics, including adhesion to epithelial cells, production of antimicrobial compounds, and activation of receptors that prompt the transcription of immune-associated genes. Recently, this species has been used in animal production. Different studies have shown that the application of L. fermentum strains not only improves the intestinal ecosystem but also reduces the effects caused by potentially pathogenic microorganisms. These studies have also revealed key insights into the mechanisms behind the actions exerted by this probiotic. In this manuscript, we aim to provide a concise overview of the effects of L. fermentum administration on broiler chicken health and performance.

High yield production of cyanidin-derived pyranoanthocyanins using 4-vinylphenol and 4-vinylguaiacol as cofactors

Pyranoanthocyanins are anthocyanin-derived pigments with vivid colors and enhanced stability, making them promising food colorants. We evaluated two 4-vinylphenols, decarboxylated p-coumaric (pCA) and ferulic acid (FA), as cofactors for pyranoanthocyanin formation. Cyanidin-3-glycosides from saponified black carrot were incubated with 4-vinylphenol or 4-vinylguaiacol in different anthocyanin-to-cofactor molar ratios (1:1-1:30) to form pyranoanthocyanins. Formation efficiency (45 °C, ≤96 h) was compared to their respective precursors at a 1:30 ratio. Composition changes were monitored using uHPLC-PDA-ESI-MS/MS. Pyranoanthocyanin yields with 4-vinylphenol (13.8-33.4%) were ∼12× higher than with pCA and yields with 4-vinylguaiacol (8.1-31.0%) were ∼6.5× higher than with FA. Molar ratios of 1:5 and 1:10 yielded significantly more pyranoanthocyanins. Pyranoanthocyanin formation with 4-vinylphenols followed first-order kinetics, whereas formation with hydroxycinnamic acids followed zero-order kinetics. Detection of intermediate compounds was consistent with a nucleophilic addition and aromatization formation mechanism. Overall, pyranoanthocyanin formation with 4-vinylphenols was more efficient than with hydroxycinnamic acids.

Dihydrocaffeic Acid-Is It the Less Known but Equally Valuable Phenolic Acid?

Dihydrocaffeic acid (DHCA) is a phenolic acid bearing a catechol ring and three-carbon side chain. Despite its being found in minor amounts in numerous plants and fungi of different origins, it has attracted the interest of various research groups in many fields of science, from food to biomedical applications. The review article presented herein aims to show a wider audience the health benefits and therapeutic, industrial, and nutritional potential of dihydrocaffeic acid, by sheddinglight on its occurrence, biosynthesis, bioavailability, and metabolism. The scientific literature describes at least 70 different derivatives of dihydrocaffeic acid, both those occurring naturally and those obtained via chemical and enzymatic methods. Among the most frequently used enzymes that were applied for the modification of the parent DHCA structure, there are lipases that allow for obtaining esters and phenolidips, tyrosinases used for the formation of the catechol ring, and laccases to functionalize this phenolic acid. In many studies, both in vitro and in vivo, the protective effect of DHCA and its derivatives on cells subjected to oxidative stress and inflammation were acknowledged.

Deep Eutectic Solvents Comprising Organic Acids and Their Application in (Bio)Medicine

Over the last years, we observed a significant increase in the number of published studies that focus on the synthesis and characterization of deep eutectic solvents (DESs). These materials are of particular interest mainly due to their physical and chemical stability, low vapor pressure, ease of synthesis, and the possibility of tailoring their properties through dilution or change of the ratio of parent substances (PS). DESs, considered as one of the greenest families of solvents, are used in many fields, such as organic synthesis, (bio)catalysis, electrochemistry, and (bio)medicine. DESs applications have already been reported in various review articles. However, these reports mainly described these components' basics and general properties without focusing on the particular, PS-wise, group of DESs. Many DESs investigated for potential (bio)medical applications comprise organic acids. However, due to the different aims of the reported studies, many of these substances have not yet been investigated thoroughly, which makes it challenging for the field to move forward. Herein, we propose distinguishing DESs comprising organic acids (OA-DESs) as a specific group derived from natural deep eutectic solvents (NADESs). This review aims to highlight and compare the applications of OA-DESs as antimicrobial agents and drug delivery enhancers-two essential fields in (bio)medical studies where DESs have already been implemented and proven their potential. From the survey of the literature data, it is evident that OA-DESs represent an excellent type of DESs for specific biomedical applications, owing to their negligible cytotoxicity, fulfilling the rules of green chemistry and being generally effective as drug delivery enhancers and antimicrobial agents. The main focus is on the most intriguing examples and (where possible) application-based comparison of particular groups of OA-DESs. This should highlight the importance of OA-DESs and give valuable clues on the direction the field can take.

Conversion of hydroxycinnamic acids by Furfurilactobacillus milii in sorghum fermentations: Impact on profile of phenolic compounds in sorghum and on ecological fitness of Ff. milii

The conversion of phenolic compounds by lactobacilli in food fermentations contributes to food quality. The metabolism of phenolics by lactobacilli has been elucidated in the past years but information on the contribution of specific enzymes in food fermentations remains scarce. This study aimed to address this gap by disruption of genes coding for the hydroxycimmanic acid reductase Par1, the hydroxycinnamic acid decarboxylase Pad, the hydrocinnamic esterase EstR, and strains with disruption of all three genes in Furfurilactobacillus milii FUA3583. The conversion of phenolics by Ff. milii and its isogenic mutants in sorghum fermentations was studied by LC-UV and LC-UV-MS/MS analyses. Ff. milii FUA3583 converted hydroxycinnamic acids predominantly with Par1. Vinylphenols were detected only in mutants lacking par1. A phenotype for the estR defective mutant was not identified. The formation of pyrano-3-deoxyanthocyanidins was observed only after fermentation with strains expressing Pad. Specifically, formation of these compounds was low with Ff. milii FUA3583, substantially increased in the Par1 mutant and abolished in all mutants with disrupted pad. Competition experiments with Ff. milii FUA3583 and its isogenic mutants demonstrated that expression of one of the two metabolic pathways for hydroxycinnamic acids increases the ecological fitness of the strain. Disruption of EstR in a Δpar1Δpar2Δpad background improved ecological fitness, indirectly demonstrating a phenotype of the esterase in Ff. milii. The documentation of the functionality of genes coding for conversion of hydroxycinnamic acids may support the selection of starter cultures for improved quality of fermented cereal products.

Purified Plant-Derived Phenolic Acids Inhibit Salmonella Typhimurium without Alteration of Microbiota in a Simulated Chicken Cecum Condition

Salmonella enterica serovar Typhimurium (ST) remains a predominant zoonotic pathogen because of its colonization in poultry, survivability in the environment, and increasing antibiotic-resistance pattern. Plant-derived phenolics, gallic acid (GA), protocatechuic acid (PA), and vanillic acids (VA) have demonstrated antimicrobial activity in vitro; therefore, this study collected chicken cecal fluid and supplemented it with these phenolics to evaluate their potential for eliminating ST and mod-ulating the microbiota of complex environments. ST was quantified through plating, while micro-biome analysis was performed through pair-end 16S-rRNA gene sequencing. CFU/mL of ST in cecal fluid with GA was significantly reduced by 3.28 and 2.78 log at 24 h and 48 h, while PA only had a slight numerical decrease. VA significantly reduced ST by 4.81 and 5.20 log at 24 h and 48 h. Changes in relative abundance of major phyla were observed at 24 h for samples with GA and VA as Firmicute levels increased 8.30% and 20.90%, while Proteobacteria decreased 12.86% and 18.48%, respectively. Significant changes in major genre were observed in Acinetobacter (3.41% for GA) and Escherichia (13.53% for VA), while Bifidobacterium increased (3.44% for GA) and Lactobacillus remained unchanged. Results suggest that phenolic compounds exert different effects on certain pathogens, while supporting some commensal bacteria.

Phenolic Compounds in Bacterial Inactivation: A Perspective from Brazil

Phenolic compounds are natural substances that are produced through the secondary metabolism of plants, fungi, and bacteria, in addition to being produced by chemical synthesis. These compounds have anti-inflammatory, antioxidant, and antimicrobial properties, among others. In this way, Brazil represents one of the most promising countries regarding phenolic compounds since it has a heterogeneous flora, with the presence of six distinct biomes (Cerrado, Amazon, Atlantic Forest, Caatinga, Pantanal, and Pampa). Recently, several studies have pointed to an era of antimicrobial resistance due to the unrestricted and large-scale use of antibiotics, which led to the emergence of some survival mechanisms of bacteria to these compounds. Therefore, the use of natural substances with antimicrobial action can help combat these resistant pathogens and represent a natural alternative that may be useful in animal nutrition for direct application in food and can be used in human nutrition to promote health. Therefore, this study aimed to (i) evaluate the phenolic compounds with antimicrobial properties isolated from plants present in Brazil, (ii) discuss the compounds across different classes (flavonoids, xanthones, coumarins, phenolic acids, and others), and (iii) address the structure-activity relationship of phenolic compounds that lead to antimicrobial action.

Characterization of isogenic mutants with single or double deletions of four phenolic acid esterases in Lactiplantibacillus plantarum TMW1.460

In plants, hydroxycinnamic and hydroxybenzoic acids occur mainly as esters. This study aimed to determine the contribution of individual phenolic acid esterases in Lp. plantarum TMW1.460, which encodes for four esterases: TanA, Lp_0796, Est_1092 and a homolog of Lj0536 and Lj1228 that was termed HceP. To determine which of the phenolic acid esterases present in Lp plantarum TMW1.460 are responsible for esterase activity, mutants with deletions in lp_0796, est_1092, tanB, hceP, or hceP and est_1092 were constructed. The phenotype of wild type strain and mutants was determined with esters of hydroxycinnamic acids (chlorogenic acid and ethyl ferulate) and of hydroxybenzoic acids (methyl gallate, tannic acid and epigallocatechin-3-gallate). Lp. plantarum TMW1.460 hydrolysed chlorogenic acid, methyl ferulate and methyl gallate but not tannic acid or epigallocatechin gallate. The phenotype of mutant strains during growth in mMRS differed from the wild type as follows: Lp. plantarum TMW1.460ΔhceP did not hydrolyse esters of hydroxycinnamic acids; Lp. plantarum TMW1.460ΔtanB did not hydrolyse esters of hydroxybenzoic acids; disruption of est_1092 or Lp_0796 did not alter the phenotype. The phenotype of Lp. plantarum TMW1.460ΔΔhceP/est_1092 was identical to Lp. plantarum TMW1.460ΔhceP. The metabolism of phenolic acids during growth of the mutant strains in broccoli puree and wheat sourdough did not differ from metabolism of the wild type strain. In conclusion, esters of hydroxycinnamic and hydroxybenzoic acids each are hydrolysed by dedicated enzymes. The hydroxycinnamic acid esterase HceP is not expressed, or not active during growth of Lp. plantarum TMW1.460 in all food substrates.

Conversion of Phenolic Acids in Canola Fermentation: Impact on Antimicrobial Activity against Salmonella enterica and Campylobacter jejuni

Canola meal (CM) is commonly used in poultry feeds. CM has a high protein content but also contains high levels of antimicrobial phenolic acids. Lactic acid bacteria can alter CM phenolic composition during fermentation and influence its antimicrobial activity against pathogens. Fermented CM was analyzed for phenolic composition using tandem mass spectrometry (LC-MS/MS) and high-performance liquid chromatography (HPLC). Sinapic acid and derivatives were the major phenolic acids in CM. Growth of lactobacilli in CM was attenuated when compared to cereal substrates. Glucosides and esters of sinapic acid were extensively hydrolyzed during fermentation with Lactiplantibacillus plantarum and Furfurilactobacillus milii. Lp. plantarum transformed hydroxycinnamic acids to dihydro, 4-vinyl, and 4-ethyl derivatives, Ff. milii reduced hydroxycinnamic acids to dihydroderivatives, but Limosilactobacillus reuteri did not convert hydroxycinnamic acids. The minimum inhibitory concentration of phenolic extracts was assessed with lactobacilli, Salmonella, and Campylobacter jejuni as indicator strains. Fermentation of CM with Lp. plantarum or Ff. milii increased the antimicrobial activity of phenolic extracts against Salmonella enterica and Campylobacter jejuni. Fermentation with Lm. reuteri TMW1.656 but not fermentation with Lm. reuteri TMW1.656ΔrtcN increased the antimicrobial activity of extracts owing to the production of reutericyclin. This study demonstrates that fermentation of CM with lactobacilli converts hydroxycinammic esters and may increase the antimicrobial activity of phenolic compounds in CM against pathogens.

Impact of Lactic Acid Bacteria Fermentation on Phenolic Compounds and Antioxidant Activity of Avocado Leaf Extracts

The growing global consumption of avocados, associated with contents including bioactive compounds with numerous health-promoting properties, is producing a large amount of agro wastes around the world. Different management approaches are available for the recovery of bioactive compounds from wastes as potential ingredients for use in the production of functional foods and nutraceuticals. Lactic acid fermentation can be used to exploit nutritional potential and add value to agro wastes. In this study, fermentations with lactic acid bacteria were carried out in avocado leaves, and the total phenolic content and the antioxidant activity were determined by DPPH and FRAP assays from hydroalcoholic extracts obtained from fermented avocado leaves. Fifteen new phenolic compounds were identified for the first time in avocado leaves by HPLC-ESI-TOF-MS. L. plantarum CECT 748T and P. pentosaceus CECT 4695T showed the highest antioxidant activity. The sum of phenolic compounds was increased by 71, 62, 55 and 21% in fermentations with P. pentosaceus CECT 4695T, L. brevis CECT 5354, P. acidilactici CECT 5765T and L. plantarum CECT 9567, respectively, while it was reduced in the fermentation with L. plantarum 748T by 21% as demonstrated by HPLC-ESI-TOF-MS. Biotransformations induced by bacterial metabolism modified the phenolic compound profile of avocado leaves in a strain-specific-dependent manner. P. pentosaceus CECT 4695T significantly increased kaempferol, P. pentosaceus 4695T, L. brevis 5354 and L. plantarum 9567 increased rutin, and dihydro-p-coumaric acid was increased by the five selected lactic acid bacteria. Total flavonoids were highly increased after fermentations with the five selected lactic acid bacteria but flavonoid glucosides were decreased by L. plantarum 748T, which was related to its higher antioxidant activity. Our results suggest that lactic acid bacteria led the hydrolysis of compounds by enzymatic activity such as glycosidases or decarboxylase and the release of phenolics bound to the plant cell wall, thus improving their bioavailability.

Future Antimicrobials: Natural and Functionalized Phenolics

With incidence of antimicrobial resistance rising globally, there is a continuous need for development of new antimicrobial molecules. Phenolic compounds having a versatile scaffold that allows for a broad range of chemical additions; they also exhibit potent antimicrobial activities which can be enhanced significantly through functionalization. Synthetic routes such as esterification, phosphorylation, hydroxylation or enzymatic conjugation may increase the antimicrobial activity of compounds and reduce minimal concentrations needed. With potent action mechanisms interfering with bacterial cell wall synthesis, DNA replication or enzyme production, phenolics can target multiple sites in bacteria, leading to a much higher sensitivity of cells towards these natural compounds. The current review summarizes some of the most important knowledge on functionalization of natural phenolic compounds and the effects on their antimicrobial activity.

Conversion of (poly)phenolic compounds in food fermentations by lactic acid bacteria: Novel insights into metabolic pathways and functional metabolites

Lactobacillaceae are among the major fermentation organisms in most food fermentations but the metabolic pathways for conversion of (poly)phenolic compounds by lactobacilli have been elucidated only in the past two decades. Hydroxycinnamic and hydroxybenzoic acids are metabolized by separate enzymes which include multiple esterases, decarboxylases and hydroxycinnamic acid reductases. Glycosides of phenolic compounds including flavonoids are metabolized by glycosidases, some of which are dedicated to glycosides of plant phytochemicals rather than oligosaccharides. Metabolism of phenolic compounds in food fermentations often differs from metabolism in vitro, likely reflecting the diversity of phenolic compounds and the unknown stimuli that induce expression of metabolic genes. Current knowledge will facilitate fermentation strategies to achieve improved food quality by targeted conversion of phenolic compounds.

Improved antioxidant capacity of three Brassica vegetables by two-step controlled fermentation using isolated autochthone strains of the genus Leuconostoc spp. and Lactiplantibacillus spp

The aim of this study was to determine the evolution of total phenolic content and antioxidant activity during controlled fermentation of three different Brassicaceae and compare it with spontaneous fermentations. The two-step controlled fermentation was carried out with lactic acid bacteria selected by their biotechnological properties. The selected bacteria were genotypically identified as Leuconostoc mesenteroides ssp. jonggajibkimchii, Ln. mesenteroides ssp. dextranicum, Lactiplantibacillus plantarum ssp. argentoratensis, L. plantarum and L. pentosus. The total phenolic content did not show a trend when comparing the different fermentations; it depended on the type of extract and vegetable. The controlled fermentation exhibited higher antioxidant activity than spontaneous fermentations for all the vegetables during the process. The extracts of red cabbage exhibited a total phenolic content and antioxidant activity higher than chinese and white cabbage, regardless of the type of fermentation.

An integrated process for wet scrubber wastewater treatment using electrooxidation and pressure-driven membrane filtration

In this study, the electrooxidation (EO) and membrane processes were used for chemical oxygen demand (COD) and total phenol (TPh) removal from wet scrubber wastewater (WSW). EO experiments were carried out using Al, Fe, SS, Ti, graphite, active carbon cloth electrodes and Box-Behnken design were used for optimization of maximum COD and TPh removal efficiency. Moreover, membrane filtration experiments were conducted to EO process using nanofiltration (NF270) and reverse osmosis membranes (SW30 and BW30). The maximum COD (55%) and TPh (50%) removal efficiency was achieved at pH of 8, 150 A/m² current density, and 180 min reaction time in EO process. Membrane filtration results showed that COD removal efficiency was the highest for SW30 membrane (95.18%) compared to BW30 (91.15%) and NF270 (80.11%) membranes. TPh removal efficiency in the NF270, BW30, and SW30 membranes was 27.08%, 96.06%, and 98.02%, respectively. The effect of microbial cell viability of the raw and treated wet scrubber wastewater after electrooxidation and membrane filtration was also investigated using E. coli. In addition to these, biofilm inhibition of the raw wet scrubber wastewater and the treated WSW after EO and membrane filtration were tested and the highest biofilm inhibition was found as 76.43% and 72.58% against S. aureus and P. aeruginosa, respectively, in 1/20 diluted samples of the raw WSW. This study suggests that the integrated process using EO and pressure-driven membrane methods are an efficient strategy for COD and TPh removal from WSW.

Metabolite Pattern Derived from Lactiplantibacillus plantarum-Fermented Rye Foods and In Vitro Gut Fermentation Synergistically Inhibits Bacterial Growth

SCOPE

Fermentation improves many food characteristics using microbes, such as lactic acid bacteria (LAB). Recent studies suggest fermentation may also enhance the health properties, but mechanistic evidence is lacking. The study aims to identify a metabolite pattern reproducibly produced during sourdough and in vitro colonic fermentation of various whole-grain rye products and how it affects the growth of bacterial species of potential importance to health and disease.

METHODS AND RESULTS

The study uses Lactiplantibacillus plantarum DSMZ 13890 strain, previously shown to favor rye as its substrate. Using LC-MS metabolomics, the study finds seven microbial metabolites commonly produced during the fermentations, including dihydroferulic acid, dihydrocaffeic acid, and five amino acid metabolites, and stronger inhibition is achieved when exposing the bacteria to a mixture of the metabolites in vitro compared to individual compound exposures.

CONCLUSION

The study suggests that metabolites produced by LAB may synergistically modulate the local microbial ecology, such as in the gut. This could provide new hypotheses on how fermented foods influence human health via diet-microbiota interactions.

Characterization of the Biological Activities of a New Polyphenol-Rich Extract from Cinnamon Bark on a Probiotic Consortium and Its Action after Enzymatic and Microbial Fermentation on Colorectal Cell Lines

Cinnamon polyphenols are known as health-promoting agents. However, their positive impact depends on the extraction method and their bioaccessibility after digestion. In this work, cinnamon bark polyphenols were extracted in hot water and subjected to an in vitro enzymatic digestion. After a preliminary characterization of total polyphenols and flavonoids (respectively 520.05 ± 17.43 µgGAeq/mg and 294.77 ± 19.83 µgCATeq/mg powder extract), the extract antimicrobial activity was evidenced only against Staphylococcus aureus and Bacillus subtilis displaying a minimum inhibition growth concentration value of 2 and 1.3 mg/mL, respectively, although it was lost after in vitro extract digestion. The prebiotic potential was evaluated on probiotic Lactobacillus and Bifidobacterium strains highlighting a high growth on the in vitro digested cinnamon bark extract (up to 4 × 10⁸ CFU/mL). Thus, the produced SCFAs and other secondary metabolites were extracted from the broth cultures and determined via GC-MSD analyses. The viability of healthy and tumor colorectal cell lines (CCD841 and SW480) was assayed after the exposition at two different concentrations (23 and 46 µgGAeq/mL) of the cinnamon extract, its digested, and the secondary metabolites produced in presence of cinnamon extract or its digested, showing positive protective effects against a tumorigenic condition.

Evaluation of antibacterial activity of compounds isolated from the peel of Newhall navel orange

Fifteen compounds including one flavanone hesperitin (1), two cinnamic acid derivatives as (E)-4-hydroxycinnamic acid (2) and (E)-ferulic acid (3), eight polymethoxyflavones (PMFs) (4-11), and four hydroxylated PMFs (12-15) isolated from orange peel were subjected to antibacterial evaluation. Compounds 1-3 exhibited wide-spectrum antibacterial effects against four test strains involving Bacillus subtilis, Staphylococcus aureus, Xanthomonas citri subsp. citri (Xcc), and Meticillin-resistant Staphylococcus aureus (MRSA) with minimum inhibitory concentrations (MICs) ranging from 0.0312 to 0.125 mg/mL. In contrast, all PMFs showed weak antibacterial activity against these four strains with MICs being equal to or more than 0.125 mg/mL. Hydroxylated PMFs demonstrated better antibacterial effect against Xcc relative to PMFs. In addition, the synergistic effect against Xcc was obtained when compounds 1 and 3 were combined. Furthermore, the scanning electron microscopy (SEM) results of Xcc treated with both compounds 2 and 3 showed shrunken and rough surface morphologies, indicative of the cell membrane damage.

Individual Phenolic Acids in Distillery Stillage Inhibit Its Biomethanization

Polyphenols that are abundant in various organic wastes can inhibit anaerobic degradation of these wastes. This study investigated the effect of the concentration of individual phenolic acids (p-OH benzoic, vanillic, ferulic, sinapic, syringic, and p-coumaric acids) and their mixture on the methane potential of distillery stillage. An increase in phenolic acid concentration adversely affected biogas production and composition, as well as the methane-production rate. The inhibition constants for methane production were 0.5–1.0 g/L of individual phenolic acids and 1.5 g/L of the mixture of these acids. At lower concentrations, the phenolic acids were utilized as a carbon source, but the process was impeded when their concentrations exceeded the threshold value, due to their negative effect on microbial growth. When distillery stillage was spiked with vanillic acid, two-phase methane production was observed. Spiking distillery stillage with vanillic, p-coumaric, syringic, or ferulic acids affected anaerobic digestion the most; 2 g/L of these acids completely inhibited methane production. With 4.0 g/L of all individual phenolic acids, no methane production was observed. As the concentration of these phenolic acids increased from 0.5 to 4.0 g/L, the abundance of methanogenic Archaea, in which acetoclastic methanogens predominated, decreased by about 30 times.

Antibacterial activities of polyphenols against foodborne pathogens and their application as antibacterial agents

Polyphenols are secondary metabolites produced in higher plants. They are known to possess various functional properties in the human body. Polyphenols also exhibit antibacterial activities against foodborne pathogens. Their antibacterial mechanism is based on inhibiting bacterial biofilm formation or inactivating enzymes. Food-derived polyphenols with such antibacterial activity are natural preservatives and can be used as an alternative to synthetic preservatives that can cause side effects, such as allergies, asthma, skin irritation, and cancer. Studies have reported that polyphenols have positive effects, such as decreasing harmful bacteria and increasing beneficial bacteria in the human gut microbiota. Polyphenols can also be used as natural antibacterial agents in food packaging system in the form of emitting sachets, absorbent pads, and edible coatings. We summarized the antibacterial activities, mechanisms and applications of polyphenols as antibacterial agents against foodborne bacteria.

Phenolic Acids - Versatile Natural Moiety With Numerous Biological Applications

BACKGROUND

Medicinal uses of natural phenolic acids and its synthetic derivatives have been augmented in recent years. Phenolic acids are chemically defined secondary plant metabolitesand being moieties or leads are much versatile in nature with a widescope of biological activities which seek the attention of researchers across the worldto synthesize different derivatives of phenolic acids and screen them for their various biological properties.These compounds are of meticulous interest due to the properties they possess and their occurrence.Based on the convincing evidences reported in the literature, it is suggested that phenolic acids andtheir derivatives are promising molecules as a drug.

OBJECTIVE

The present review article aims to bring together the information on the biosynthesis, metabolism, and sources of phenolic acids and emphasize on the therapeutic potential of phenolic acid and its synthetic derivatives to comprehensively portray the current scenery for researchers interested in designing drugs for furthering this study.

CONCLUSION

Phenolic acids being moieties or lead are much versatile in nature as they possess a wide range of biological activities like antimicrobial, antioxidant, antiviral, antiulcer, anti-inflammatory, antidiabetic, anticancer and many more which offers researchers to explore more about these or many untapped benefits in medicinal field. The information mentioned in this article will be helpful to the forthcoming researchers working in this area. Phenolic acids have massive potential to be investigated for novel medicinal possibilities and for the development of new chemical moieties to treat different diseases of clinical importance.

How Microbiome Composition Correlates with Biochemical Changes during Sauerkraut Fermentation: a Focus on Neglected Bacterial Players and Functionalities

This study provided a new perspective on the bacterial community succession during sauerkraut fermentation, and on resulting metabolic functions. While culture-dependent methods confirmed the key role of the well-known core microbiome species, metagenomic approach (shotgun) revealed Secundilactobacillus malefermentans as a species of the core microbiome, especially during the last weeks of fermentation. Although the potentiality of S. malefermentans has not yet fully explored, it held core functional genes usually attributed to others lactic acid bacteria driving sauerkraut fermentation. Based on our results it is arguable that S. malefermentans might have a key a role during sauerkraut fermentation carried out at low temperature. Under our experimental conditions, the profile of phenolic compounds changed throughout sauerkraut fermentation. The amount of free phenolics, including free phenolic acids, increased at the beginning of the fermentation, whereas the conversion of phenolic acids into microbial derivatives was consistent during the last part of the sauerkraut fermentation. We pioneered correlating changes in the phenolics profile to changes in the microbiome, although the framework presented is still fragmentary. Annotated genes linked to the phenolic compounds metabolism (VprA and padA) were found in many core species during the whole process. A high metabolic potential for phenolics bioconversion emerged for lactobacilli and Pediococcus spp. through correlation analysis between microbiome composition and phenolics profile.

IMPORTANCE Our study was not limited to describe the succession pattern of the microbial community during sauerkraut fermentation, but also revealed how some neglected bacterial players belong to the core species during sauerkrauts processing, especially at low temperature. Such species might have a role as potential starters to optimize the fermentation processes and to obtain sauerkrauts with improved and standardized nutritional and sensory features. Furthermore, our correlations between microbiome composition and phenolics profile might also represent new references for sauerkraut biotechnology, aiming to identify new metabolic drivers of potential sauerkraut functionalities. Finally, sauerkraut ecosystem is a tractable model, although with high level of complexity, and resultant ecological information might be extended to other plant ecosystems.

Bee Pollen Extracts: Chemical Composition, Antioxidant Properties, and Effect on the Growth of Selected Probiotic and Pathogenic Bacteria

This paper evaluated the chemical and biological properties of bee pollen samples from Romania. Firstly, the bee pollen alcoholic extracts (BPEs) were obtained from raw bee pollen harvested by Apis mellifera carpatica bees. The chemical composition of BPE was obtained by determination of total phenol content and total flavonoid content, UHPLC-DAD-ESI/MS analysis of phenolic compounds, and GC-MS analysis of fatty acids, esters, and terpenes. Additionally, the antioxidant activity was evaluated by the Trolox Equivalent Antioxidant Capacity method. Furthermore, the biological properties of BPE were evaluated (antimicrobial and cytotoxic activity). The raw BP samples studied in this paper had significant phenolic acid and flavonoid content, and moderate fatty acid, ester, and terpene content. P1, P2, and P4 have the highest TPC and TFC levels, and the best antioxidant activity. All BPEs studied had antimicrobial activity on pathogenic strains isolated from the clinic or standard strains. A synergistic antimicrobial effect of the BPEs was observed along with the soluble compounds of L. rhamnosus MF9 and E. faecalis 2M17 against some pathogenic (clinical) strains and, considering the tumour proliferation inhibitory activity, makes BP a potential prebiotic and antitumour agent for the gut environment.