Natural Antimicrobials Research Articles

Plants with Antimicrobial Activity against Escherichia coli, a Meta-Analysis for Green Veterinary Pharmacology Applications.

Antimicrobial resistance (AMR) poses a critical global health threat, necessitating innovative strategies to combat infectious diseases. Plants and their extracts offer alternatives/support to traditional antibiotics, and their diverse phytocomplexes with antimicrobial properties can be exploited. The Mediterranean hosts a high number of biodiverse plant species known for their bioactive compounds. This study focuses on identifying plant species and phytochemical constituents with antimicrobial activity against Escherichia coli (E. coli). Utilizing a systematic literature review and meta-analysis approach, we screened 3037 entries, yielding 70 studies suitable for MIC (minimum inhibitory concentration) annotation. The results highlighted Lavandula spp., Plectranthus spp. and Lupinus jaimehintoniana as the most effective plants with average MICs of, respectively, 0.144 mg/mL, 0.260 mg/mL, and 0.140 mg/mL. These results might help to fight AMR via the discovery of complementary natural antimicrobial agents to support the development of green veterinary pharmacology. Further exploration of these resources promises valuable insights for future support to antimicrobial strategies.

Long-term mold resistance strategy of laccase-catalyzed eugenol-modified bamboo and its antimicrobial mechanism derived from lignin

Bamboo, which has excellent physical properties and environmental credentials, is widely used in the construction industry and furniture manufacturing. Bamboo is, however, susceptible to attack by molds and bacteria; protection by natural phenolic antimicrobial agents would be a green and environmentally friendly solution to this problem. The application of such protection has, so far, been hampered by poor stability and ease of volatilization of the antimicrobial agent. Here, an innovative strategy that uses the catalytic action of the laccase to chemically attach a natural antimicrobial agent, eugenol (EU), to bamboo, is described. This modification endows bamboo with both long-lasting and extensive mold resistance and antibacterial activity. Laccase-catalyzed covalent bonding of EU to bamboo reduces the volatilization rate of the EU from 1.72 % to 0.29 %. The outstanding mold resistance and antimicrobial activity of bamboo treated using this modified process is retained during a 50-day mold resistance test, with mold growth inhibited by as much as 87.5 %. The treated bamboo is also able to inhibit the growth of both Gram-positive and Gram-negative bacteria. The antimicrobial mechanism results shown that the bamboo lignin is the primary reaction site during laccase-catalyzed EU modification of bamboo, and the long-term mold resistance derived from modified lignin. Furthermore, we analyzed bacterial morphology through SEM, and the results demonstrated that modified enzymatic hydrolysis lignin (EHL) significantly disrupts bacterial morphology, including membrane invagination and collapse. This study provides a new direction for the green development of mold- and bacteria-resistant bamboo, which has potential for use in a wide range of application.

Potential of Non-Saccharomyces Yeasts as Probiotics and Alternatives to Antibiotics in Animal Production.

Probiotics are live yeast or bacterial organisms that have beneficial effects on the host. Several microorganisms exhibit probiotic properties, the most common types being lactic acid bacteria, Bifidobacteria, spore-forming bacteria, and some yeast strains. Saccharomyces cerevisiae var. boulardii is the most important probiotic yeast species. However, another group of foodborne microorganisms, the so-called non-Saccharomyces yeasts (NSYs), has recently been re-evaluated and shown to have enormous potential in various fields of application, ranging from food fermentation to human and animal applications. NSYs are able to produce a range of bioactive compounds such as antimicrobials, mannoproteins, enzymes, polyunsaturated fatty acids, essential amino acids, vitamins, and β-glucans, which increases their potential applications as a new class of probiotics and/or alternatives to antibiotics in animal husbandry. In this review, we aim to highlight the potential and benefits of NSYs as probiotics and natural antimicrobials to improve animal health. Furthermore, the use of NSYs as biological alternatives to antibiotics to control foodborne pathogens in animal production is discussed.

Anti-biofilm and antioxidant activities of Sargassum muticum extracts and their preservation effect of Chinese shrimp (Penaeus chinensis)

Vibrio parahaemolyticus can enhance bacterial resistance to disinfectants and antimicrobials by forming biofilms. The development of new natural antimicrobials is essential for the control of biofilm-related contamination and infection. In this paper, we preliminarily explored the inhibitory activity of Sargassum muticum extracts (HA-PTs) against the biofilm of V. parahaemolyticus. HA-PTs exerted anti-biofilm activity by destroying the integrity of the cell membrane, curbing the motility of single and colonial bacteria, hindering the synthesis of polysaccharide intercellular adhesion, inhibiting the secretion of extracellular DNA, and reducing the metabolic activity of biofilms. Furthermore, experiments on four free radicals (DPPH•, •OH, ABTS+•, and O2−•) scavenging activity and total antioxidant capacity (FRAP method and phenanthroline method) demonstrated that HA-PTs have strong reducing properties and can capture a variety of free radicals, which in turn prevents them from participating in oxidative reactions. When HA-PTs were applied to Chinese shrimp infected with V. parahaemolyticus, it could prolong their shelf life by controlling the pH rise caused by protein degradation, inhibiting the bacterial proliferation, reducing the content of total volatile basic nitrogen produced by protein degradation, and reducing the accumulation of thiobarbiturates caused by oxidative deterioration of fats.

Antibacterial activity of a polysaccharide isolated from litchi (Litchi chinensis Sonn.) pericarp against Staphylococcus aureus and the mechanism investigation

The long-term use of antibiotics can cause drug resistance. Natural polysaccharides are a novel means of treating bacterial infections, and the development and utilization of litchi pericarp polysaccharide (LPPs) as a bacteriostatic active substance offer a new research direction for the high-value utilization of litchi by-products. This study revealed that LPPs inhibited Staphylococcus aureus more than Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium, with the minimum inhibitory concentrations of 145, 205, 325, and 445 μg/mL, respectively. The inhibitory activity of LPPs was insignificant for Bacillus subtilis at 505 μg/mL. The assessment of antibacterial mechanisms revealed that LPPs influenced the growth, conductivity, protein, and nucleic acid, reducing sugar, respiratory chain dehydrogenase activity, bacterial lipid peroxidation, intracellular adenosine triphosphate, and extracellular alkaline phosphatase levels of S. aureus. Of note, LPPs could modify the cell wall integrity and cell membrane permeability of S. aureus, resulting in the leakage of intracellular large and small molecules, inhibition of cellular respiratory metabolism, and oxidative losses. These processes exhibited an inhibitory effect and made the bacterium nonfunctional, thereby affecting its growth and metabolism or causing cell death. These findings provide support and insights into the potential application of LPPs as a natural antimicrobial agent.

Cymbopogon distans: A source of essential oil with potential antibacterial, antifungal, and mosquito-repelling properties

The essential oils have become increasingly popular in recent years due to their potential as natural antimicrobial agents and a means of controlling mosquitoes. This study explored the chemical composition and antibacterial, antifungal, and mosquito-repellent properties of Cymbopogon distans (Nees ex Steud.) Wats (Poaceae) is a less explored aromatic plant distributed in the Himalayas. The fresh biomasses of C. distans and two commercially grown Cymbopogon species, namely C. flexuous and C. martini were submitted to hydrodistillation to extract their essential oils. Gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analyses revealed the presence of citral, geraniol, and geranyl acetate as major constituents of C. distans. The essential oils of C. flexuous and C. martini were dominated by citral and geraniol, respectively. Antibacterial and antifungal activities of C. distans essential oil were evaluated using disc diffusion and micro-dilution methods and compared with the essential oils of C. flexuous and C. martini. C. distans essential oil showed a broader spectrum of potent antibacterial and antifungal activities (minimum inhibitory concentration: 0.41 mg/ml and minimum bactericidal concentration/minimum fungicidal concentration: 0.82 mg/ml) against the test strains. C. distans essential oil, in combination with norfloxacin and penicillin G showed synergistic interactions (fractional inhibitory concentration ≤0.5) against Staphylococcus aureus and Staphylococcus epidermidis. C. distans essential oil showed a repellent effect against Aedes aegypti (73.3 %) that was comparable to C. winterianus essential oil (75.6 %). This study suggests that C. distans essential oil may be a promising natural candidate for developing new herbal therapies for combating microbial infections and mosquito-borne diseases.

Modulating the Release Kinetics of Natural Product Actinomycin from Bacterial Nanocellulose Films and Their Antimicrobial Activity.

The present study aimed to create a more sustainable and controlled delivery system based on natural biopolymer bacterial nanocellulose (BNC) and bacterial natural product actinomycin (Act), with the applicative potential in the biomedical field. In order to provide improved interaction between BNC and the active compound, and thus to modulate the release kinetics, the TEMPO oxidation of BNC support was carried out. A mix of actinomycins from bacterial fermentation (ActX) were used as natural antimicrobial agents with an established bioactivity profile and clinical use. BNC and TEMPO-oxidized BNC films with incorporated active compounds were obtained and analyzed by FTIR, SEM, XPS, and XRD. The ActX release profiles were determined in phosphate-buffer solution, PBS, at 37 °C over time. FTIR analysis confirmed the improved incorporation and efficiency of ActX adsorption on oxidized BNC due to the availability of more active sites provided by oxidation. SEM analysis indicated the incorporation of ActX into the less-dense morphology of the TEMPO-oxidized BNC in comparison to pure BNC. The release kinetics of ActX were significantly affected by the BNC structure, and the activated BNC sample indicated the sustained release of active compounds over time, corresponding to the Fickian diffusion mechanism. Antimicrobial tests using Staphylococcus aureus NCTC 6571 confirmed the potency of this BNC-based system for biomedical applications, taking advantage of the capacity of modified BNC to control and modulate the release of bioactive compounds.

Production and characterisation of antioxidant and antibacterial polymeric nanoparticles loaded with Oenocarpus bataua phenolic extract

SummaryOne recent trend in the food industry is using natural antioxidants and antimicrobials as additives for developing multi‐functional packaging. In this study, phenolic compounds from patawa (PEP), a neglected Amazon palm tree, were extracted and encapsulated in nanoparticles based on acetylated cashew gum polysaccharide (acCGP) and chitosan (CS) using a nanoprecipitation technique. The primary objective was to evaluate the antioxidant activity and antibacterial properties of PEP and acCGP/CS@PEP. Results from HPLC‐MS showed that PEP is mainly composed of epicatechin, naringenin and rutin. acCGP/CS@PEP nanoparticles showed a spheric and smooth microstructure, observed with 40.1% PEP encapsulation into the nanoparticles. The main encapsulated phenolics were luteolin, quercetin and epicatechin. Also, FTIR spectroscopy, X‐ray diffraction and differential scanning calorimetry analyses evidenced the success of PEP encapsulation. Results from antioxidant activity evidenced that acCGP/CS@PEP has a DPPH scavenging activity 45‐fold higher than the unencapsulated PEP, a 5‐fold higher ferric reducing power and 20‐fold higher antioxidant potential against ABTS. Similarly, acCGP/CS@PEP had higher antibacterial activity against Escherichia coli (MIC = 2.24 mg mL−1), Salmonella enteritis (MIC = 4.48 mg mL−1) and Staphylococcus aureus (MIC = 4.48 mg mL−1). Analysis by SEM evidenced that acCGP/CS@PEP had a potent destructive effect with disruption of the bacterial cell membrane and liberation of cytoplasmic content. These findings demonstrated that PEP could be efficiently encapsulated in acCGP/CS nanoparticles, and this strategy could improve the efficiency of PEP as a bioactive compound for developing active packaging.

Chitosan-based functional coatings for postharvest processing of tomatoes

The review article includes information on the use of coatings, both from chitosan itself and in combination with other polysaccharides and functional compounds, for postharvest processing, mainly of tomatoes, to extend the shelf life of harvested produce. During harvesting of fruits and vegetables, losses due to fungal infection can be as high as 50%. To prevent yield losses and preserve fruit quality, various methods of postharvest treatment are used. Currently, the most effective means used to control postharvest diseases are synthetic fungicides, but their uncontrolled use negatively affects human health and the environment. Recently, there has been a continuing trend to increase the use of natural antimicrobial agents. Such natural compounds can be chitin and chitosan, they are renewable, biodegradable, low toxicity and safe for consumers and the environment. The film-forming ability of chitosan and its antimicrobial, antioxidant properties are important for obtaining functional coatings for postharvest processing of fruits.

Fabrication of smart nanogel based on carrageenan and green coffee extract as a long-term antifouling agent to improve biofilm prevention in food production

This study investigates the extract of the bioactive compounds from green coffee extract (GCE) and the loading of two different concentrations of GCE (1% and 2%) onto carrageenan nanogels (CAR NGs) to compare their antibacterial and antibiofilm effects with unloaded nanogels (NGs). The bioactive compounds of GCE were characterized using GC–MS analysis. The GCE1 and GCE2 were successfully deposited onto the surface of CAR NGs. The antibacterial and antibiofilm potential of prepared NGs were conducted against some foodborne pathogens (E. coli O157, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes). The results of GC–MS analysis indicated that there were identified 16 bioactive compounds in GCE, including caffeine (36.27%), Dodemorph (9.04%), and D-Glycero-d-ido-heptose (2.44%), contributing to its antimicrobial properties. The antibacterial coatings demonstrated a notable antimicrobial effect, showing zone of inhibition (ZOI) diameters of up to 37 mm for GCE2 loaded CAR NGs. The minimum inhibitory concentration (MIC) values for GCE2 loaded CAR NGs were 80 ppm for E. coli O157, and 120 ppm for S. enterica, S. aureus, and L. monocytogenes, achieving complete bacterial inactivation within 10–15 min of exposure. Both GCE1 and GCE2 loaded CAR NGs significantly reduced biofilm cell densities on stainless steel (SS) materials for E. coli O157, S. enterica, S. aureus, and L. monocytogenes, with reductions ranging from 60% to 95%. Specifically, biofilm densities were reduced by up to 95% for E. coli O157, 89% for S. enterica, 85% for S. aureus, and 80% for L. monocytogenes. Results of the toxicity evaluation indicated that the NGs were non-toxic and biocompatible, with predicted EC50 values proved their biocompatibility and safety. These results recommended that GCE loaded CAR NGs are promising as natural antimicrobial agents for enhancing food safety and extending shelf life. Further, the study concluded that incorporating GCE into CAR NGs is an effective strategy for developing sustainable antimicrobial coatings for the food industry and manufacturing.

Formulation of novel functional extrudates containing natural bioactive compounds

Incorporating natural antimicrobial agents into food systems is a promising alternative to synthetic additives. This study developed corn-based functional extrudates enriched with essential oils from oregano, rosemary, chamomile, and hypericum (EOB) via twin screw extrusion processing. EOB was introduced in both encapsulated and non-encapsulated forms using electrohydrodynamic processing, spray drying, and freeze drying within a whey protein isolate and pullulan matrix. Extrudates containing spray-dried EOB (SP-EOB) achieved the highest extrusion efficiency (72.94% ± 1.16%). Morphological analysis revealed homogeneous structures for XE and XS extrudates, while XF extrudates were more porous. The gastrointestinal release kinetics of EOB from the extrudates were best described by the Korsmeyer-Peppas model, indicating an anomalous diffusion mechanism with “n” values ranging from 0.480 to 0.650. These findings highlight the potential for naturally bioactive and sustainable food products via advanced processing methods, reducing dependence on synthetic additives.

Evaluation of the antibacterial and antifungal properties of oleuropein, olea Europea leaf extract, and thymus vulgaris oil

BackgroundAlthough synthetic preservatives and antioxidants may have high antimicrobial and antioxidant activity, they are usually associated with adverse effects on human health. Currently, there is a growing interest in natural antimicrobial and antioxidant agents. This study aimed to evaluate the antimicrobial activity of two medicinal plant extracts and one active compound. Olive leaf extracts (0.2, 0.3, and 0.4% w/v), oleuropein (0.2, 0.4, and 0.6% w/v), thyme oil (0.1%), and oleuropein in combination with thyme oil (0.4% w/v and 0.1% v/v) were used against three bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus) and two fungal strains (Candida albicans and Aspergillus niger).ResultsThe use of oleuropein resulted in complete antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli. In this context, a reduction of 7 logs was achieved during the storage period (4 weeks). Oleuropein showed no fungal activity at low concentrations (0.2%), but Aspergillus niger was reduced by 2.35 logs at higher concentrations (0.6% w/v). Similar antibacterial and antifungal properties were observed for the olive leaf extracts. Oleuropein at a concentration of 0.4 w/v and a mixture of oleuropein and thyme at concentrations of 0.4 and 0.1 (v/v) showed strong antimicrobial activity against the studied microorganisms.ConclusionOlive leaf extract, thyme oil, and oleuropein have strong antibacterial and weak antifungal properties. There was a good synergistic effect between oleuropein and thymol.

Fennel (Foeniculum vulgare Mill.) essential oil: The chemical profile, biological activity, and utilization of the commercial products

Laboratory-isolated essential oils are commonly used in experiments regarding their utilization as natural antioxidant and antimicrobial agents. This study analyzed commercially available essential oils (Serbian-FSR and Russian-FRU) of fennel (Foeniculum vulgare Mill.) and added to the pork patties to investigate their possible role as natural antioxidant and antimicrobial agents. Chemical analysis of the samples showed significant differences in profiles caused by geographical origin and other environmental factors. The main compound in both samples was trans-Anethole, but it had a much higher content in Serbian oils. On the contrary, Russian oil had a high portion of anisaldehyde and linalool. These diversities are the main reason for thermal behavior and biological activity differences. The thermal analysis has shown that FSR had a crystalline form in the solid state, while FRU had an amorphous form. During heating, in FSR, a single-step weight loss was detected, while in FRU, a two-step weight loss was observed, indicating that, in addition to evaporation, components in FRU interacted with each other, forming lesser volatile molecules. After adding pork patties, Russian oil showed higher potency and better protective behavior than Serbian oil. Moreover, mixtures of these oils were added to the patties samples, and results showed higher potency when compared to individual oil samples. This indicated that minor compounds from both oils interacted and synergistically acted to prolong the shelf life of the meat samples. Commercial essential oils could be successfully utilized to prolong shelf life and provide additional intake of natural compounds significant for the human diet.

Antioxidant and antimicrobial activities of Myrtus communis essential oils in cold-stored lactic butter.

The use of natural antioxidants and antimicrobials in dairy production can increase the variety of dairy-based products. In this study, the antioxidant and antimicrobial changes in lactic butter samples made from heat-treated creams and enriched with M. communis essential oils (EOs) were investigated. The best lactic butter properties were achieved by optimizing the process at 70 and 80 °C. M. communis EOs decreased lipid oxidation and spoilage microorganism growth in lactic butter during cold storage. M. communis EOs have antioxidant and antimicrobial activity in lactic butter equal to that of ascorbyl palmitate. α-Pinene, p-cymene, limonene, 3-carene, 1,8-cineol, β-linalool, α-terpineol and myretenol are the major contributors to the antioxidant and antimicrobial activities of M. communis EOs. They exhibit antioxidant activity by neutralizing free radicals by donating hydrogen or acting as termination enhancers, and antimicrobial activity by disruption of cell membranes, which may result in the leakage of macromolecules or the loss of essential metabolites, ultimately leading to cell death during the storage of lactic butter samples. The addition of M. communis EOs improves lactic butter stability equal to that of ascorbyl palmitate, and may be applied as a natural and effective preservative to maintain butter from lipid oxidation and microbial spoilage and enhance its safety. The growing recognition of the health benefits of natural antioxidants, as opposed to synthetic ones, has led to the development of new applications for natural antioxidants. In this regard, M. communis L. EOs can be used to enhance the shelf stability of cold-stored lactic butter. © 2024 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The bactericidal effect of punicalagin concentrations, high pressure conditions and their combination on Escherichia coli O157: H7

Punicalagin (PUN), as a natural antimicrobial agent, is the most abundant phenolic compound in pomegranate peel. In this study, the bactericidal effect of PUN concentrations, high pressure conditions and their combination on E. coli O157: H7 were investigated. The bacteria were suspended in physiological saline solution with PUN concentrations of 1–3 mg/mL and treated by high pressures of 100–300 MPa for 2–10 min. The synergistic effect of the combination treatment was demonstrated with the maximum enhancement value of 4.10. Cell morphology changes, membrane permeability enhancement and swimming motility inhibition were observed in the combination treatment. Adenosine, adenine, cyclic GMP in purine metabolism and glutathione in glutathione metabolism pathways were differential metabolites with content changes, which were related with treatment methods (HPP or PUN) but not the degree of bacteria inactivation. This study provided a more effective and innovative method for killing E. coli in simulation system. Industrial relevanceHPP was the most commercialized emerging non-thermal processing technology and PUN was the natural antibacterial agent from pomegranate peel waste. The combination of HPP and PUN had synergistic bactericidal effect on E. coli with less processing intensity, which was very suitable for the products those contained thermosensitive components with maximum sensory characteristics preserved and less preservative added.

ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF LEAVES OF MEDICINAL PLANT Hibiscus tiliaceus L.

Antimicrobial agents are very important in the medical world. The agent is used as a surgical and intensive care procedure. However, bacteria have become resistant to the antibiotics used. Apart from that, antioxidants are also needed in the medical world as neuroprotectives and preventing free radicals in the body so as to avoid degenerative diseases. Hibiscus tiliaceus L or better known in Indonesia is a waru plant, containing various active compounds such as alkaloids, flavonoids, tannins and saponins that can be used as alternatives as natural antimicrobials and antioxidants. The purpose of writing this review article is to determine the antimicrobial and antioxidant potential of hibiscus plants (Hibiscus tiliaceus L.). The method used in this review article is a literature study obtained from sciencedirect, researchgate and google scholar regarding the benefits of Hibiscus tiliaceus L. leaf extract as an antimicrobial and antioxidant through a literature search process using research articles from the last 10 years. Based on research that has been carried out, it shows that Hibiscus tiliaceus L. leaves extract has the potential to be a natural antimicrobial and antioxidant.

ANTIBACTERIAL ACTIVITY OF BACANG MANGO (Mangifera foetida L.) LEAVES ETHANOL EXTRACT IN GEL FORMULATION AS ANTI-ACNE

Acne was a chronic skin disorder that was most often found in adolescents, so it frequently caused psychological effects that made the acne fighters look for ways to treat it quickly. Although topical antibiotics effectively treat acne, excessive long-term use can cause resistance. This has led to an interest in natural antimicrobials as an alternative treatment for acne. The natural antibacterial activity of the ethanol extract of bacang mango (Mangifera foetida L.) leaves has previously been reported to have antibacterial effects against Propionibacterium acnes, but only in the form of extracts not formulated into pharmaceutical preparations. Therefore, this study aimed to re-test the antibacterial activity of this extract, which has now been formulated into a gel preparation against the same bacteria. The gelling agent used in the gel formulation was Na-CMC with three different concentrations: 3%, 4%, and 5%. The Agar stab technique tests the antibacterial activity for three different extract concentrations. Those were 10%, 15%, and 20% for optimization of inhibitory activity before being formulated. Based on the results of testing the antibacterial activity of the ethanol extract of bacang mango (Mangifera foetida L.) leaves, an extract concentration of 20% had a more potent inhibitory activity than the others so that this concentration was chosen to be formulated into a gel preparation. After the formulation of the extracted gel, Na-CMC with a concentration of 5% produced a better gel base than other formulations. In addition, the three formulations provided the same inhibitory activity of 10 mm, so it can be concluded that the differences in gelling agent concentrations did not affect the antibacterial activity of the extracts in the preparations. However, a 3 mm decrease in inhibition occurred in the extract after it was formulated into a gel preparation. Even so, the extract gel preparation still has antibacterial activity against Propionibacterium acnes with antimicrobial inhibition zone activity, which is in the moderate category.

Characterization of free radical-mediated Pleurotus ostreatus polysaccharide-EGCG conjugates for chilled minced pork preservation

To improve the functions of Pleurotus ostreatus polysaccharide (POP), POP-EGCG conjugates were prepared using free radical graft polymerization reactions and were characterized using UV–vis, FT-IR, SEM, XRD, DSC, TG, particle size and potential, three-phase contact angle, and rheological tests; The antioxidant and antibacterial ability in vitro were detected. Moreover, effects of POP-EGCG on the quality of refrigerated minced pork were investigated. The results showed the optimal preparation conditions of POP-EGCG were 1 % POP, 1.3 % EGCG, 0.25 % Vc, 16 % concentration of H2O2, and reaction 17 h. The POP-EGCG showed the characteristic peak of EGCG and was a mesh honeycomb with rough and porous surface; It had higher crystallinity, increased particle size, but decreased thermal stability, solubility, and viscosity, and significantly enhanced antioxidant and antibacterial ability. The POP-EGCG effectively improved the sensory quality and inhibited lipid oxidation of chilled minced pork, and extended the shelf life of minced pork up to 9 days at 4 °C. Specifically, the TVB-N and TBARS of minced pork in the POP-EGCG group were respectively 14.93 mg/100 g and 0.9 mg MDA/kg, which were lower than the spoilage thresholds in the national standard. This study provides a theoretical basis for further development of natural antioxidants and antimicrobial agents.

Analytical and Antimicrobial Characterization of Zn-Modified Clays Embedding Thymol or Carvacrol.

Carvacrol and thymol are broad-spectrum natural antimicrobial agents. To reduce their volatility and improve their antimicrobial performance, synergistic systems were prepared loading the active molecules in zinc-modified clays. Montmorillonite (MMT) and zeolite (ZEO) were modified with zinc ions (ZnMMT and ZnZEO), with well-known antimicrobial properties, and then with carvacrol or thymol, reaching the 26 ± 3% and 33 ± 2% w/w of loading, respectively. The resulting hybrid materials were characterized by FT-IR, XPS, XRD, TGA, and GC-MS to evaluate carvacrol/thymol release in simulating food matrices. Antimicrobial assays carried out using spoiler and pathogenic bacterial strains showed that the antimicrobial activity of both thymol and carvacrol was largely preserved once they were loaded into Zn-modified clays. However, MMT hybrids showed an antibacterial activity significantly higher than ZEO hybrids at 50 mg/mL of thymol and carvacrol. For this reason, deeper antimicrobial evaluations were carried out only for ZnMMT composites. ZnMMT loaded with thymol or carvacrol produced inhibition zones against most of the target strains, also at 3.12 mg/mL, while the positive controls represented by the single molecule thymol or carvacrol were not active. The hybrid materials can be useful for applications in which the antimicrobial activity of natural molecules need to be displayed over time as requested for the control of microbial pathogens and spoilage bacteria in different applications, such as active packaging, biomaterials, and medical devices.

Are Mouthwashes Really Effective against Candida spp.?

Oral candidiasis is an opportunistic infection caused by fungi of the genus Candida. Nystatin, fluconazole, and miconazole are the most widely used antifungal drugs in dentistry, but in recent years, they have been shown to be less effective due to the increase in the resistance to antifungal drugs. The growing challenge of antifungal resistance emphasizes the importance of exploring not only alternative strategies in the fight against Candida spp. infections but also supportive treatment for pharmacological treatment for oral candidiasis. This review aims to evaluate and compare the in vitro reports on antifungal efficacy against Candida spp. exhibited by mouthwashes distributed on the European market. The research question was elaborated through the PEO framework recommended by PRISMA 2020. A bibliographic search strategy was developed for the scientific online databases Pubmed and ScienceDirect. According to the eligibility criteria, 21 papers were included in this study over a 27-year period. Mouthwashes containing chlorhexidine digluconate, cetylpyridinium chloride, hexetidine, and fluorine compounds among others, and natural antimicrobials, such as menthol, thymol, eucalyptol, and Glycyrrhiza glabra extracts, have demonstrated antifungal effectiveness. Nonetheless, the methodological variance introduces ambiguity concerning the comparative efficacy of distinct molecules or mouthwash formulations and complicates the evaluation and the comparison of results between studies. Some mouthwashes commercially available in Europe have the potential to be used in anti-Candida therapy and prevention since they have shown antifungal effect.