Antimicrobial Effects Research Articles

Microbial contamination of spittoons and germicidal effect of irradiation with krypton chloride excimer lamps (Far UV-C 222 nm).

In dentistry, instruments, appliances, and body fluids such as saliva or blood are possible sources of infection. Although conventional antiseptic procedures effectively prevent infection, spittoons cannot be sanitized between each treated patient and are usually washed only with running water. However, there is currently no fast and efficient disinfection method that can be implemented between treatments. An optically filtered krypton chloride excimer lamp using ultraviolet light (Far UV-C) in the 200-230 nm wavelength range (innocuous to humans) has been recently used as a virus- and bacteria-inactivating technology. This study aimed to identify the bioburden of a dental spittoon and examine the susceptibility of two oral Streptococcus and two Enterococci to 222-nm Far UV-C by irradiating the spittoon with 222 nm Far UV-C for 5 min before evaluating the disinfection effect. Bacterial analysis and real-time polymerase-chain reaction testing was used to confirm the spittoon's biological contamination. Bacterial susceptibility to a 222-nm Far UV-C was determined with a graded dose irradiation test. After each treatment, the spittoon was irradiated with 222-nm Far UV-C for 5 min, and the disinfecting effect was evaluated. Microbial analysis of the spittoon's surface was performed using the Silva database. We found that > 97% of the microbes consisted of six bacterial phyla, whereas no viruses were found. Pseudomonas aeruginosa was frequently detected. The 1-log reduction value of two oral-derived Streptococci and two Enterococci species at 222-nm Far UV-C was 4.5-7.3 mJ/cm2. Exposure of the spittoon to 222-nm Far UV-C at 3.6-13.5 mJ/cm2 significantly decreased bacterial counts (p < 0.001). Irradiation with 222-nm Far UV-C at 3.6-13.5 mJ/cm2 significantly eliminates bacteria in spittoons, even when they are only rinsed with water. Hence, 222-nm Far UV-C irradiation may inhibit the risk of bacterial transmission from droplets in sink surfaces.

Relationships of Prodiginins Mechanisms and Molecular Structures to their Antiproliferative Effects.

The Prodiginins (PGs) natural pigments are secondary metabolites produced by a broad spectrum of gram-negative and gram-positive bacteria, notably by species within the Serratia and Streptomyces genera. These compounds exhibit diverse and potent biological activities, including anticancer, immunosuppressive, antimicrobial, antimalarial, and antiviral effects. Structurally, PGs share a common tripyrrolic core but possess variable side chains and undergo cyclization, resulting in structural diversity. Studies have investigated their antiproliferative effects on various cancer cell lines, with some PGs advancing to clinical trials for cancer treatment. This review aims to illuminate the molecular mechanisms underlying PG-induced apoptosis in cancer cells and explore the structure-activity relationships pertinent to their anticancer properties. Such insights may serve as a foundation for further research in anticancer drug development, potentially leading to the creation of novel, targeted therapies based on PGs or their derivatives.

Anti-microbial, anti-biofilm, and efflux pump inhibitory effects of ellagic acid-bonded magnetic nanoparticles against Escherichia coli isolates.

The spread of microbial resistance is a threat to public health. In this study, the anti-microbial, anti-biofilm, and efflux pump inhibitory effects of ellagic acid-loaded magnetic nanoparticles (Fe3O4NPs@EA) against beta-lactamase producing Escherichia coli isolates have been investigated. The effects of Fe3O4 NPs@EA on the growth inhibition of E. coli isolates were determined by disc diffusion method and determining the minimum inhibitory concentration was done using broth micro-dilution method. The anti-biofilm effect of nanoparticles was investigated using the microplate method. The efflux pump inhibitory effect of nanoparticles was investigated using cart-wheel method and by investigating the effect of nanoparticles on acrB and tolC genes expression levels. Fe3O4 NPs@EA showed anti-bacterial effects against test bacteria, and the MIC of these nanoparticles varied from 0.19 to 1.56 mg/mL. These nanoparticles caused a 43-62% reduction in biofilm formation of test bacteria compared to control. Furthermore, efflux pump inhibitory effect of these nanoparticles was confirmed at a concentration of 1/8 MIC, and the expression of acrB and tolC genes decreased in bacteria treated with 1/4 MIC Fe3O4 NPs@EA. According to the results, the use of nanoparticles containing ellagic acid can provide a basis for the development of new treatments against drug-resistant E. coli. This substance may improve the concentration of antibiotics in the bacterial cell and increase their effectiveness by inhibiting the efflux in E. coli isolates.

Ferulic Acid: A Review of Mechanisms of Action, Absorption, Toxicology, Application on Wound Healing.

This work aims to make a bibliographic survey on studies of the use of ferulic acid in the treatment of wounds. The studies found show that ferulic acid acts through different mechanisms of action such as antioxidant, anti-inflammatory, antimicrobial, collagen production, angiogenic, and reepithelialization effects. These properties act synergistically in different stages of healing, which differentiates it from conventional treatments. In addition, ferulic acid has dermal absorption, low skin metabolism, and low toxicity. Studies in this area are recent and further research is needed to expand the possibilities and therapeutic efficiency of ferulic acid in wound healing.

Composition, Bioactivities, Microbiome, Safety Concerns, and Impact of Essential Oils on the Health Status of Domestic Animals

Essential oils (EOs) are highly concentrated and volatile blends of nonpolar substances that are derived from aromatic plant components and comprise terpenes, terpenoids, and phenylpropanoids, exhibiting diverse biological and pharmacological properties. The burgeoning pet industry is interested in EOs as a potential solution for common health issues in domestic animals, particularly in addressing antimicrobial resistance. The present literature review summarizes the composition, properties, benefits, safety considerations, and effects of EOs on domestic animals. The applications of EOs range from antimicrobial effects to antioxidant, anti-inflammatory, and anticancer activities, etc. The chemical constituents of EOs, exemplified by eucalyptus EO and rosemary EO, highlight their distinct aromatic profiles and potential benefits. Nevertheless, understanding the chemical makeup of EOs is fundamental to assessing their potential impacts on biological systems. The gut microbiota plays a crucial role in regulating various metabolic processes in the host, including energy homeostasis, glucose metabolism, and lipid metabolism. Safety considerations, including potential toxicity risk awareness, are essential when incorporating EOs into animal care routines. The feed additives incorporating EOs have shown promise in influencing gut microbiota balance, reducing inflammation, and acting as antioxidants. However, considering the potential risks associated with high doses or multiple administrations, cautious application is paramount. Preliminary studies suggest low toxicity levels, but further research is required to evaluate the safety of EOs. Though studies have reported the beneficial effects of EOs on pets and animals, further research is needed to validate the findings in real-world conditions. The paper also discussed the regulatory considerations and future perspectives on applying EOs in veterinary medicine.

Could light be a broad-spectrum antimicrobial?

A review on antimicrobial resistance mechanisms discussing the main light-based antimicrobial approaches including ultraviolet light (UV), antimicrobial photodynamic therapy (aPDT), and antimicrobial blue light (aBL). To describe antimicrobial resistance mechanisms and to present potential light-based alternatives to conventional antimicrobials. The paper was divided into different topics, starting with an approach to antimicrobial resistance mechanisms. Subsequently, emphasis was placed on innovative light-based antimicrobials approaches, including aBL, UV, and aPDT. The review suggests that blue light (400-470 nm) acts on endogenous porphyrins with peak absorption at 405 nm, thus not requiring the administration of photosensitizers, to trigger antimicrobial effects. In this regarding, the direct effect of aBL could be attributed to both the generation of reactive oxygen species (ROS), which induces microbicidal effects, and the inactivation of bacterial defense mechanisms. In turn, blue light combined with curcumin has been used in the treatment of dental infections. Otherwise, green light (495-570 nm) associated with the photosensitizer Rose Bengal has shown promising results both in wound closure due to the induction of additional collagen cross-link formation and in reducing the viability of Pseudomonas aeruginosa. Red light (620-750 nm) is the wavelength most commonly used in aPDT, presenting superior tissue penetration capability compared to blue and green light. Both red and infrared light act directly as photobiomodulation agents, promoting tissue repair with greater penetration depth for the infrared spectrum. Conversely, red light combined with methylene blue is the most commonly used technique in the treatment of localized infections. Meanwhile, infrared light associated with indocyanine green acts as a photothermal and photosensitizing agent, promoting thermal damage and production of ROS. Ultraviolet lights UVA, UVB, and UVC (200-400 nm) have antimicrobial potential related to inducing changes in DNA and generating both ROS and singlet oxygen. Furthermore, light can enhance the efficacy of traditional antimicrobial agents by deactivating microbial resistance, both through increasing the permeability of the cell membrane and by inhibiting the efflux pump and β-lactamases of the bacteria. The antimicrobial potential of light is extensive; however, there is a limitation regarding the depth of penetration of certain wavelengths into infected areas. Furthermore, there is a need for additional studies to determine the safety and efficacy of various approaches using light at its different wavelengths.

Antimicrobial Effect of Chitosan Nanoparticles and Allium Species on Mycobacterium tuberculosis and Several Other Microorganisms

This study evaluates the antimicrobial efficacy of chitosan nanoparticles (CNPs), varying in size, against clinical isolates of Mycobacterium tuberculosis (MTB), E. coli, S. aureus, E. faecalis, and C. albicans, as well as the antimicrobial effects of aqueous extracts and lyophilized powders of Allium (garlic) species. CNPs were synthesized through ionotropic gelation and characterized by Z potential, hydrodynamic diameter (dynamic light scattering, DLS), and SEM. Aqueous garlic extracts were prepared via decoction. We assessed antimicrobial activity using disk diffusion and broth microdilution methods; in addition, a modified agar proportion method in blood agar was used for antimicrobial activity against MTB. CNPs inhibited MTB growth at 300 μg for 116.6 nm particles and 400 μg for 364.4 nm particles. The highest antimicrobial activity was observed against E. faecalis with nanoparticles between 200 and 280 nm. Allium sativum extract produced inhibition for C. albicans at 100 μg. The results indicate that CNPs possess significant antimicrobial properties against a range of pathogens, including MTB, at high concentrations. On the other hand, aqueous Allium sativum extracts exhibited antimicrobial activity. Nonetheless, due to their instability in solution, the use of lyophilized Allium sativum powder is preferable.

Biocide-encapsulated core–shell polymer microspheres: A novel approach for preparing long-lasting antimicrobial coatings

Antimicrobial coatings play a crucial role in combating pathogenic microorganisms. However, developing long-lasting antimicrobial coatings presents substantial challenges. In this study, we developed a robust method for fabricating durable antimicrobial coatings using crosslinked, biocide-encapsulated core–shell polymer microspheres. These microspheres were prepared by emulsion polymerization, facilitating simultaneous synthesis and biocide loading. Designed with a hydrophilic shell and a hydrophobic core, the microspheres predominantly stored the hydrophobic biocides within the core, thus reducing the biocide concentration at the shell. This design, which is governed by Fickian diffusion, substantially slowed the rate of biocide migration from the shell to the external environment, thereby enhancing the coating's antimicrobial longevity. The synthetic process for these biocide-encapsulated microspheres was optimized to encapsulate biocides with a Log P range of 1–3, achieving an encapsulation efficiency exceeding 85 % for all tested biocides. Specifically, microspheres containing N-butyl-1,2-benzisothiazolin-3-one (BBIT) were used to develop an antimicrobial coating. The coating can be applied to various substrates, including glass, metal, wood, ceramics, and plastics. It exhibits excellent hardness, adhesion, mechanical strength, and solvent resistance on these surfaces. Antimicrobial tests and release analyses demonstrated that the coating maintains high biological activity for at least 10 months, effectively inhibiting bacterial and fungal growth. The release behavior of the coating adhered to the Peppas–Sahlin model, with diffusion as the predominant mechanism. The model predicted an antimicrobial retention rate of over 66 % after 1 year, confirming its sustained antimicrobial effectiveness.

Guided Plasma Application in Dentistry—An Alternative to Antibiotic Therapy

Cold atmospheric plasma (CAP) is a promising alternative to antibiotics and chemical substances in dentistry that can reduce the risk of unwanted side effects and bacterial resistance. AmbiJet is a device that can ignite and deliver plasma directly to the site of action for maximum effectiveness. The aim of the study was to investigate its antimicrobial efficacy and the possible development of bacterial resistance. The antimicrobial effect of the plasma was tested under aerobic and anaerobic conditions on bacteria (five aerobic, three anaerobic (Gram +/−)) that are relevant in dentistry. The application times varied from 1 to 7 min. Possible bacterial resistance was evaluated by repeated plasma applications (10 times in 50 days). A possible increase in temperature was measured. Plasma effectively killed 106 seeded aerobic and anaerobic bacteria after an application time of 1 min per 10 mm2. Neither the development of resistance nor an increase in temperature above 40 °C was observed, so patient discomfort can be ruled out. The plasma treatment proved to be effective under anaerobic conditions, so the influence of ROS can be questioned. Our results show that AmbiJet efficiently eliminates pathogenic oral bacteria. Therefore, it can be advocated for clinical therapeutic use.

Bacterial reduction and temperature increase of titanium dental implant models treated with a 445 nm diode laser: an in vitro study

In this in vitro study, the use of a 445 nm diode laser was investigated for the decontamination of titanium dental implants. Different irradiation protocols and the effect of repetitive laser irradiation on temperature increase and decontamination efficacy were evaluated on titanium implant models. An automated setup was developed to realize a scanning procedure for a full surface irradiation to recapitulate a clinical treatment. Three irradiation parameter sets A (continuous wave, power 0.8 W, duty cycle (DC) 100%, and 5 s), B (pulsed mode, DC 50%, power 1.0 W, and 10 s), and C (pulsed mode, DC 10%, power 3.0 W, and 20 s) were used to treat the rods for up to ten consecutive scans. The resulting temperature increase was measured by a thermal imaging camera and the decontamination efficacy of the procedures was evaluated against Escherichia coli and Staphylococcus aureus, and correlated with the applied laser fluence. An implant’s temperature increase of 10 °C was set as the limit accepted in literature to avoid thermal damage to the surrounding tissue in vivo. Repeated irradiation of the specimens resulted in a steady increase in temperature. Parameter sets A and B caused a temperature increase of 11.27 ± 0.81 °C and 9.90 ± 0.37 °C after five consecutive laser scans, respectively, while parameter set C resulted in a temperature increase of only 8.20 ± 0.53 °C after ten surface scans. The microbiological study showed that all irradiation parameter sets achieved a complete bacterial reduction (99.9999% or 6-log10) after ten consecutive scans, however only parameter set C did not exceed the temperature threshold. A 445 nm diode laser can be used to decontaminate dental titanium rods, and repeated laser irradiation of the contaminated areas increases the antimicrobial effect of the treatment; however, the correct choice of parameters is needed to provide adequate laser fluence while preventing an implant’s temperature increase that could cause damage to the surrounding tissue.

Antibacterial Activity of Ethanol Extract from Australian Finger Lime

Australian finger lime (Citrus australasica L.) has become increasingly popular due to its potent antioxidant capacity and health-promoting benefits. This study aimed to determine the chemical composition, antibacterial characteristics, and mechanism of finger lime extract. The finger lime extracts were obtained from the fruit of the Australian finger lime by the ethanol extraction method. The antibacterial activity of the extract was examined by detecting the minimum inhibitory concentration (MIC) for two Gram-positive and four Gram-negative bacterial strains in vitro, as well as by assessing variations in the number of bacteria for Candidatus Liberibacter asiaticus (CLas) in vivo. GC-MS analysis was used to identify the antibacterial compounds of the extract. The antibacterial mechanisms were investigated by assessing cell permeability and membrane integrity, and the bacterial morphology was examined using scanning electron microscopy. The extract demonstrated significant antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and Gram-negative bacterial species, such as Escherichia coli, Agrobacterium tumefaciens, Xanthomonas campestris, Xanthomonas citri, and CLas. Among the six strains evaluated in vitro, B. subtilis showed the highest susceptibility to the antimicrobial effects of finger lime extract. The minimum inhibitory concentration (MIC) of the extract against the tested microorganisms varied between 500 and 1000 μg/mL. In addition, the extract was proven effective in suppressing CLas in vivo, as indicated by the lower CLas titers in the treated leaves compared to the control. A total of 360 compounds, including carbohydrates (31.159%), organic acid (30.909%), alcohols (13.380%), polyphenols (5.660%), esters (3.796%), and alkaloids (0.612%), were identified in the extract. We predicted that the primary bioactive compounds responsible for the antibacterial effects of the extract were quinic acid and other polyphenols, as well as alkaloids. The morphology of the tested microbes was altered and damaged, leading to lysis of the cell wall, cell content leakage, and cell death. Based on the results, ethanol extracts from finger lime may be a fitting substitute for synthetic bactericides in food and plant protection.

Acne: role of Cutibacterium acnes and possibilities of using bacteriophages

BACKGROUND: The role of Cutibacterium acnes in the pathogenesis of acne vulgaris and its adverse effect on follicular hyperkeratosis, inflammation and the skin microbiome have now been established. Their excessive colonization contributes to the loss of microbial diversity of the skin, activates the innate immune system, leads to the appearance of skin rash elements and chronic inflammation. Bacteriophages are considered as a new promising direction in the treatment of patients with acne, as they have an antimicrobial effect against C. acnes; contribute to the preservation of the skin microbiome; have an indirect effect on the innate and adaptive immune response. AIM: To evaluate the effectiveness and safety of topical therapy with cosmetic gel with bacteriophages Fagoderm in the complex treatment of patients with moderate to severe acne. MATERIALS AND METHODS: In the design of a simple open prospective study in parallel groups, the effect of cosmetic gel with bacteriophages on the number of comedones, pupules and pustules was assessed in 35 adult patients with moderate acne. During therapy, possible adverse events were simultaneously recorded. RESULTS: During therapy, similar dynamics were noted in the form of a decrease in non-inflammatory elements of acne both in the group of people receiving a combination of adapalene and phagoderm, and in the comparison group, where monotherapy with adapalene was carried out. The number of inflammatory elements of acne decreased in both groups, but in the main group this happened at an earlier time. Compared to the initial data, already in the 2nd week the number of inflammatory elements decreased by 50% (in comparison ― by 32%); by the end of the 4th ― by 95% (respectively in the comparison group ― by 74%). CONCLUSION: Cosmetic gel with bacteriophages with bacteriophages helps reduce the inflammatory manifestations of moderate acne.

Alginate composite films incorporated with Zn-based inorganic antimicrobials for food packaging: Effects of morphology.

Biopolymers-based food packaging materials have drawn attention as potential candidates for substitution of petroleum-based materials. In this study, composite alginate films were developed by incorporating Zn-based antimicrobials to overcome the intrinsic disadvantages of alginates that hinder their wide applications. Antimicrobials with different morphologies (nanoplatelets, nanorods, and nanospheres) were employed to investigate the effects of antimicrobials' morphology on antibacterial, thermal, mechanical, and barrier performance of composite alginate films. Meanwhile, morphological and structural characterizations were carried out to explore the interactions between antimicrobials and alginate matrix. Results indicated that films with nanospheres exhibited superior antibacterial property, while those with one-dimensional nanorods possessed better mechanical and barrier performance. Besides, preliminary test on fresh-cut potatoes and chicken breasts indicated that the composite films showed potential in extending shelf life of foods. By incorporating antimicrobials with three different morphologies, this study provides particular insights into improving properties of composite packaging materials.

Integrated metabolomics analysis of chill-stored rose shrimp (Parapenaeus longirostris) treated with different pressure levels of high hydrostatic pressure by 1H-NMR spectroscopy.

The antimicrobial effects of high hydrostatic pressure (HHP) treatments on chill-stored seafood are well-documented, while their impact on the metabolic profile of seafood, especially the metabolome of fish flesh, and remains underexplored. Addressing this gap, this study investigates the effects of HHP on the metabolome of chill-stored rose shrimp by conducting multivariate data analysis based on untargeted proton nuclear magnetic resonance observations. Vacuum-packed rose shrimp samples were subjected to HHP at 0, 400, 500, and 600MPa for 10 min and then stored at 2-4°C. The microorganism analysis and metabolic analysis were carried out on days 1 and 14. HHP treatment effectively deactivated Lactobacillus spp., Escherichia coli, Pseudomonas spp., total Coliforms, and sulfite-reducing anaerobic bacteria. Consequently, HHP treatment significantly reduced the formation rate of decay-related metabolites, such as hypoxanthine, trimethylamine, and biogenic amines, which exhibited significant accumulation in untreated samples. Multivariate unsupervised analyses provided insights into the overall changes in the metabolite profile induced by HHP. Metabolic pathway analysis revealed several pathways underlying spoilage, including pyruvate metabolism, valine, leucine, and isoleucine biosynthesis, purine metabolism, methane metabolism, glycine, serine, and threonine metabolism, citrate cycle (TCA cycle), glycolysis/gluconeogenesis, alanine, aspartate, and glutamate metabolism, sulfur metabolism, pantothenate and CoA biosynthesis, glutathione metabolism, and glyoxylate and dicarboxylate metabolism. Importantly, these pathways underwent alterations due to the application of HHP, particularly at high-pressure levels. In summary, the results unveil the potential mechanisms of HHP effects on chill-stored rose shrimps.

Antimicrobial effect of (2-chloro-4-cyano-5-ethoxy-3,5-dioxopentan-2-yl) phosphonic acid against pathogenic bacteria and fungi

The synthesized organic compound ((2-chloro-4-cyano-5-ethoxy-3,5-dioxopentan-2-yl) phosphonic acid)) was evaluated against pathogenic microorganisms using agar well diffusion method. The results obtained reveled that, the diameters of inhibition zones were ranging between 24.0-36.3 mm for gram-negative bacteria, from 28.3 mm to 34.5 mm for gram-positive bacteria and between 18.2-20.3 mm for genus Candida. The MIC value 62.5 µg/mL showed that among gram-negative bacteria, Escherichia coli and Pseudomonas aeruginosa were the most sensitive to the compound compared to Acinetobacter baumannii and Klebsiella pneumoniae. Gram-positive bacteria (Staphylococcus aureus, Bacillus mesentericus and Bacillus subtilis) had the same sensitivity to the compound with 125 µg/mL as MIC value. Among fungal strains, Candida tropicalis with MIC value 62.5 µg/mL was the most sensitive to the compound compared to Candida albicans (250 µg/mL) and Candida guilliermondii (125 µg/mL).

Exploring the Biological Applications of TiO2 and AgNPs: Innovations and Impacts

The foundation for crucial industrial applications and rapid expansion is now nanotechnology. The nanoparticles are synthesized by various methods that are classified into bottom-up or top-down method Ag NPs show antimicrobial effect and are possibly useful in the areas of food preservation, antibacterial surfaces and tissues, nanomedicine, and dentistry, TiO2 NPs are one of the most widely generated metal oxide NPs, which is typically because of its adaptable and acceptable qualities that come from the optical, electrical, chemical properties, and physical. Its various kinds of minerals include anatase, rutile, and brookite; generally, the former has more TiO2 due to increased photocatalytic activity. Despite TiO2 NPs' relevance, very little work has been done to generate them sustainably. Nanoparticles have many applications likes engineering of tissue antimicrobial applications, and regenerative medicine, carrier for drug delivery, cancer Treatment, the major aim of the essay to provide overview about silver and titanium nanoparticles their application in medicine especially how the penetration occur

Assessment of Antimicrobial Activity of Chitosan, ZnO, and Urtica dioica-ZnO NPs Against Staphylococcus aureus Isolated from Diabetic Ulcers.

Staphylococcus aureus (S. aureus) is considered as one of the challenging ulcer infections in diabetic patients especially those who have acquired antibiotic-resistant infections. Nanotechnology products have enormous potential to treat diseases including infectious diseases. As chitosan and zinc oxide (ZnO) nanoparticles (NPs) have harbored a high antimicrobial effect, this survey was aimed to synthesize chitosan, ZnO, and ZnO-Urtica. diocia (ZnO-U. diocia) NPs, and to assess their antimicrobial effects and their influence on virulencegenes expression in S. aureus isolates from diabetic ulcers. The antibacterial effect of NPs was detected by microdilution method. The most frequently components in U. diocia aqueous extract were linalool,4-thujanol, camphor, carvacrol, propanedioic acid, and di(butyl) phthalate. More than 95% of clinical S. aureus isolates were resistant to several antibiotics including erythromycin, cefoxitin, clindamycin, and ciprofloxacin. The most resistant isolates were S. aureus ATDS 52, ATDS 53, F5232, and F91. The lowest MIC and MBC by the NPs on the isolates was detected as 0.128 g/mL and 0.178g/mL, respectively. A significant decrease of 90% in the expression rates of lukED and RNAIII genes was reported for S. aureus isolates treated with the NPs. The synthetized ZnO-U. diocia and chitosan NPs can be proposed as a reliable and effective antimicrobial agent targeting diabetic ulcers infections caused by S. aureus because of its high effects on the bacterial growth and virulence genes expression.

Biological Properties of Oleanolic Acid Derivatives Bearing Functionalized Side Chains at C-3

Triterpene acids are a class of pentacyclic natural carboxylic compounds endowed with a variety of biological activities including antitumor, antimicrobial, and hepatoprotective effects. In this work, several oleanolic acid derivatives were synthesized by structurally modifying them on the C-3 position. All synthesized derivatives were evaluated for possible antibacterial and antiviral activity, and among all the epimers, 6 and 7 demonstrated the best biological activities. Zone-of-inhibition analyses were conducted against two strains, E. coli as a Gram-negative and S. aureus as a Gram-positive model. Subsequently, experiments were performed using the microdilution method to determine the minimum inhibitory concentration (MIC). The results showed that only the derivative with reduced hydrogen bonding ability on ring A possesses remarkable activity toward E. coli. The conversion from acid to methyl ester implies a loss of activity, probably due to a reduced affinity with the bacterial membrane. Before the antiviral activity, the cytotoxicity of triterpenes was evaluated through a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Samples 6 and 7 showed less than 50% cytotoxicity at 0.625 and 1 mg/mL, respectively. The antiviral activity against SARS-CoV-2 and PV-1 did not indicate that triterpene acids had any inhibitory capacity in the sub-toxic concentration range.

Ferula latisecta gels for synthesis of zinc/silver binary nanoparticles: antibacterial effects against gram-negative and gram-positive bacteria and physicochemical characteristics

This study explores the potential antibacterial applications of zinc oxide nanoparticles (ZnO NPs) enhanced with silver (Ag) using plant gel (ZnO-AgO NPs). The problem addressed is the increasing prevalence of pathogenic bacteria and the need for new, effective antimicrobial agents. ZnO NPs possess distinctive physicochemical properties that enable them to selectively target bacterial cells. Their small size and high surface area-to-volume ratio allow efficient cellular uptake and interaction with bacterial cells. In this study, the average size of the synthesized ZnO-Ag nanoparticles was 77.1 nm, with a significant standard deviation of 33.7 nm, indicating a wide size distribution. The nanoparticles demonstrated remarkable antibacterial efficacy against gram-negative and gram-positive bacteria, with inhibition zones of 14.33 mm for E. coli and 15.66 mm for B. subtilis at a concentration of 300 µg/ml. Minimum inhibitory concentrations (MIC) were determined to be 100 µg/ml for E. coli and 75 µg/ml for S. saprophyticus. Additionally, ZnO-Ag NPs exhibited excellent biocompatibility, making them appropriate for various pharmacological uses. This study utilizes Ferula latisecta gels, offering a sustainable and eco-friendly approach to nanoparticle synthesis. Incorporating of Ag into ZnO NPs significantly enhances their antimicrobial properties, with the combined results showing great inhibition effects on pathogenic microbes. The findings suggest that ZnO-Ag NPs could be a promising candidate for addressing the challenges posed by drug-resistant bacterial infections and enhancing antimicrobial treatments.

Antimicrobial photodynamic therapy against Escherichia coli by exploiting endogenously produced Protoporphyrin IX- In vitro study.

Due to antimicrobial drug resistance, there is a growing interest in the development of light based alternative antibacterial therapies. This research work is focused on the inactivation of Escherichia coli (E. coli) by exploiting the absorption bands 405, 505, 542, 580 and 631nm of its indigenously produced Protoporphyrin IX (PpIX) excited by three LEDs with broad emission bands at 418, 522 and 630nm and two laser diodes with narrow emission bands at 405 and 635nm. Fluorescence spectroscopy and plate count method have been employed for studying the inactivation rate of E. coli strain in autoclaved water suspension. It has been found that LEDs at 418, 522 and 630nm produced pronounced antimicrobial photodynamic effect on E. coli strain comparing laser diodes at 405 and 635nm, which might be attributed to the overlapping of broad emission bands of LEDs with the absorption bands of PpIX than narrow emission bands of laser diodes. Particular effect of LED at 522nm has been noticed because its broad emission band overlaps three absorption bands 505, 542 and 580nm of PpIX. The gold standard plate count method strongly correlates with Fluorescence spectroscopy, making it an innovative tool to administer bacterial inactivation. The experimental results suggested the development of a light source that entirely overlap absorption bands of PpIx to produce a pronounced antimicrobial photodynamic effect, which might become an effective modality for in vivo disinfection of antibiotic resistant microbes in wounds and lesions.