Current Issue : July-September Volume : 2025 Issue Number : 3 Articles : 5 Articles
Background/Objectives: The discovery of new molecules to which bacteria have not yet developed resistance is a significant medical priority. Synthetic flavonoids are good candidates for developing new antimicrobials. Our study investigates a series of newly synthesized tricyclic flavonoids with several different substituents on the flavonoid core. Methods: By varying the nature of the substituents on rings A and B, a structure– activity relationship study using different microbial strains has been performed. The antibacterial and antifungal properties of these compounds have been investigated against Gram-positive and Gram-negative bacteria and several Candida strains. Results: All seven tested compounds have been found to exhibit the highest antimicrobial activity against S. aureus, with an inhibition zone of up to 23 mm. The tricyclic flavonoids 5c, 5e, and 5f showed good antifungal properties against C. parapsilosis, with an inhibition zone of around 17 mm. Conclusions: All the data support the idea that flavonoids 5 are reliable candidates for developing effective antimicrobial agents....
Background/Objectives: Plantaricins without a signal sequence were synthesized based on bacteriocins, plantaricins A, E, F, J, and K, of Lactiplantibacillus plantarum KM2. The antibacterial activities of four combinations of synthetic plantaricins—spPlnA, E&F, E&J, and J&K—were identified against Staphylococcus aureus ATCC 12692. And in this experiment, we aimed to identify the antimicrobial mechanism of the synthesized plantaricin sample against S. aureus. Methods/Results: The minimal inhibitory concentrations for each combination were 1.4 μg/mL, 1.8 μg/mL, 1.6 μg/mL, and 1.6 μg/mL, respectively. Raman spectra changed after treating S. aureus ATCC 12692 with synthetic plantaricins. Furthermore, transmission electron microscopy results revealed that the four synthetic plantaricin combinations could induce the cell lysis of S. aureus ATCC 12692. Finally, the four synthetic plantaricin combinations maintained their antibacterial effect at temperatures below 40 ◦C, and at pH levels of pH = (4–7). Except for spPlnJ&K, they are stable against the action of α–amylase and lysozyme. Overall, these results indicate that, excepting spPlnJ&K, the three synthetic plantaricin combinations exhibit similar antibacterial activity. Conclusions: Through this study, we confirmed that synthetic plantaricin exhibited antimicrobial activity against S. aureus, demonstrating its potential as a direct antimicrobial agent. However, since the antimicrobial activity decreased due to protease, it was confirmed that its use is limited in environments where protease is present....
Background/Objectives: Multidrug-resistant (MDR) pathogens pose a critical challenge in infection treatment. Pediococcus pentosaceus (P. pentosaceus) is known for its antimicrobial activity; however, studies on its effects against MDR pathogens remain limited. This study aimed to evaluate the antimicrobial and biological activities of P. pentosaceus PMY2, isolated from fermented porcine colostrum yogurt, against MDR pathogens, including Staphylococcus aureus (S. aureus), Pseudomonas aeruginosa (P. aeruginosa), and Escherichia coli (E. coli). Methods: The antimicrobial, anti-inflammatory, and cytotoxic effects of P. pentosaceus PMY2 were evaluated in vitro. In addition, IL-6 and TNF-α levels were analyzed using an ELISA kit. Results: The MIC value against S. aureus KCTC 3881 and MRSA (CCARM 3089) was 0.31 mg/mL, while the MBC values were 0.63 mg/mL and 2.5 mg/mL, respectively. At MIC, biofilm formation was inhibited by 62.2% in S. aureus KCTC 3881 and by 51.5% in MRSA. CFS exhibited low cytotoxicity in RAW 264.7 macrophages and significantly reduced NO production, IL-6, and TNF-α levels, indicating strong anti-inflammatory effects. Conclusions: These findings suggest that P. pentosaceus PMY2 exhibited excellent antimicrobial and anti-inflammatory activity against MDR pathogens, demonstrating its potential as a natural antimicrobial agent. These results indicate that PMY2 CFS could be a promising candidate for addressing antibiotic resistance issues....
Background/Objectives: This study aims to gain insights into the antimicrobial and antiherpetic activity of hyperforin-rich Hypericum perforatum L. (HP) extract using nanostructured lipid carriers (NLCs) as delivery platforms. Methods: Two established NLC specimens, comprising glyceryl behenate and almond oil or borage oil, and their extractloaded counterparts (HP-NLCs) were utilized. Their minimal bactericidal/fungicidal concentrations (MBC; MFC) were investigated against Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 10145, Klebsiella pneumoniae ATCC 10031, and Candida albicans ATCC 10231. The anti-herpesvirus (HSV-1) potential was evaluated concerning antiviral and virucidal activity and impact on viral adsorption. Results: The borage oil-based extract-loaded nanodispersion (HP-NLC2) exhibited pronounced microbicidal activity against S. aureus (MBC 6.3 mg/mL), K. pneumoniae (MBC 97.7 μg/mL), and C. albicans (MFC < 48.8 μg/mL), unlike the almond oil-containing sample (HP-NLC1), which showed only weak inhibition of the fungal growth. HP-NLC2 was found to be less cytotoxic and to suppress HSV-1 replication slightly more than HP-NLC1, but generally, the effects were weak. Neither the empty lipid nanoparticles nor the HP extract-loaded carriers expressed activity against E. coli, P. aeruginosa, the HSV-1 extracellular virions, or viral adhesion. Conclusions: It could be concluded that both HP-NLC samples revealed only minor antiherpetic potential of the hyperforin-rich extract, but HP-NLC2 demonstrated significant antibacterial and antimycotic activity. Therefore, the latter was featured as a more convenient HP-carrier system for nano-designed dermal pharmaceutical formulations. Such a thorough investigation of hyperforin-determined anti-HSV-1 effects and antibacterial and antimycotic properties, being the first of its kind, contributes to the fundamental knowledge of HP and reveals new perspectives for the utilization, limitations, and therapeutic designation of its non-polar components....
Background/Objectives: Biomaterials are an essential part of healthcare for both diagnostic and therapeutic procedures. Although some biomaterials possess antimicrobial properties, introducing biomaterial into the body may lead to infections due to bacterial adhesion on their surfaces and still poses a major clinical problem. Peptides derived from the human cartilage-specific C-type lectin domain family 3 member A (CLEC3A) show a potent antimicrobial effect. In addition, coating titanium, a commonly used prosthetic material, with the CLEC3A-derived AMPs HT-47 and WRK-30 greatly reduces the number of adherent bacteria in vitro. The aim of this study was to evaluate the effectiveness of CLEC3A-derived peptides HT-47 and WRK-30 in reducing bacterial adhesion and mitigating infection in vivo in a murine biomaterial-associated infection model. Methods: To do so, an in vivo mouse infection model was used, where titanium plates—either uncoated or coated with chimeric CLEC3A-derived peptides TiBP-HT-47 and TiBP-WRK- 30—were implanted subcutaneously into mice. This was followed by the introduction of Staphylococcus aureus bacterial cultures to induce a biomaterial-associated infection. After 24 h, the titanium plates, surrounding tissue, and mice blood samples were investigated. Results: CLEC3A-coated titanium plates lead to a significantly lower bacterial count than uncoated ones. Additionally, they prevent the infection from spreading to the surrounding tissue. Moreover, mice with CLEC3A-coated implants display lower IL-6 serum levels and therefore decreased systemic inflammation. Conclusions: In conclusion, in this biomaterialassociated infection mouse-model, CLEC3A-derived peptides show in vivo antimicrobial activity by reducing bacterial burden on biomaterial and wound tissue and decreasing systemic inflammation, making them promising candidates for clinical applications....
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