Search Results (11)

Currently, safe alternatives with very low toxicity and good antimicrobial activity are being sought to replace chemical compounds that can be harmful to animal and human health. For this reason, this study evaluated the safety and biofunctional microbiocidal potential of an extract composed of thymol and eucalyptol. Toxicity tests showed low toxicity in both chickens (2000 mg/kg bw) and Artemia salina (EC₅₀ = 2003 mg/L) and Daphnia magna (EC₅₀ = 87 mg/L), indicating a safe usage profile. Oxidative stress biomarkers (nitrite and MDA) and antioxidant enzymes (SOD and catalase) improved in treated chickens at 20 days of age. The hematological and biochemical parameters of the treated birds showed normal values similar to those of the control group chickens, with better protein levels and lower AST levels. Histology of the kidney, intestine, and liver showed no changes in any group, confirming the absence of systemic adverse effects. At the molecular level, an improvement in the expression of tight junction proteins (claudin and occludin) was observed, suggesting a strengthening of the intestinal barrier integrity. Finally, the extract demonstrated an antimicrobial effect (E. coli, C. perfringens, Salmonella sp. and Pseudomonas sp.) comparable to that of organic acids commonly used as food preservatives, positioning it as a promising alternative in applications. Full article

One cationic surfactant with a wide spectrum of microbiocidal activity is benzethonium chloride (BEC). Despite being widely used, the toxicity data on vertebrate organisms are limited. Therefore, we aimed to evaluate within this study the acute toxicity of BEC on the gills and kidneys of Cyprinus carpio (European carp). An alteration of the antioxidant enzymes activities (glutathione reductase, glutathione peroxidase and glutathione S-transferase) was noticed after 96 h of exposure, along with an elevation of lipid peroxidation and decreased concentration of reduced glutathione, which confirmed that BEC was able to induce toxicity to these tissues. These metabolic effects were correlated with unspecific structural changes observed in gills and kidneys, having moderate degree of severity (such as an increase of melanomacrophages aggregation incidence and cytoplasm vacuolation of goblet cells in collecting tubules) and generally being compatible with life for the exposure time studied. The most severe structural effects were observed in gills after 96 h, noticing a lamellar aneurysm, hemorrhages and lamellar epithelium disruption due to the blood vessels and pillar cells damages and increased blood flow inside the lamellae. By our research we can confirm the utility of biochemical and histological analyses in the fish organs as tools for monitoring the water quality and ecotoxicological potential of chemicals. Full article

The chemical composition and biological activities of the essential oils from the leaves, stems, and roots of Kadsura coccinea (K. coccinea) were investigated. The essential oils were extracted by hydro distillation and analyzed by gas chromatography mass spectrometry (GC-MS) and gas chromatography with flame ionization detector (GC-FID). Antioxidant activities of the essential oils were examined with DPPH radical scavenging assay, ABTS cation radical scavenging assay, and ferric reducing antioxidant power assay. Antimicrobial activities were evaluated by determining minimum inhibitory concentrations (MIC) and minimum microbiocidal concentrations (MMC). Acetylcholinesterase and butyrylcholinesterase inhibitory activity of the essential oils were also tested. A total of 46, 44, and 47 components were identified in the leaf, stem, and root oils, representing 95.66%, 97.35%, and 92.72% of total composition, respectively. The major compounds of three essential oils were α-pinene (16.60–42.02%), β-pinene (10.03–18.82%), camphene (1.56–10.95%), borneol (0.50–7.71%), δ-cadinene (1.52–7.06%), and β-elemene (1.86–4.45%). The essential oils were found to have weak antioxidant activities and cholinesterase inhibition activities. The essential oils showed more inhibitory effects against Staphylococcus aureus (S. aureus) than those of other strains. The highest antimicrobial activity was observed in the root oil against S. aureus, with MIC of 0.78 mg/mL. Therefore, K. coccinea essential oils might be considered as a natural antibacterial agent against S. aureus with potential application in food and pharmaceutical industries. Full article

The emergence of a large number of bacterial strains resistant to many drugs or disinfectants currently used contributed to the search of new, more effective antimicrobial agents. In the presented paper, we assessed the microbiocidal activity of tri- and tetranuclear oxo-titanium(IV) complexes (TOCs), which were dispersed in the poly(methyl methacrylate) (PMMA) matrix. The TOCs were synthesized in reaction to Ti(OR)₄ (R = ⁱPr, ⁱBu) and HO₂CR’ (R’ = 4-PhNH₂ and 4-PhOH) in a 4:1 molar ratio at room temperature and in Ar atmosphere. The structure of isolated oxo-complexes was confirmed by IR and Raman spectroscopy and mass spectrometry. The antimicrobial activity of the produced composites (PMMA + TOCs) was estimated against Gram-positive (Staphylococcus aureus ATCC 6538 and S. aureus ATCC 25923) and Gram-negative (Escherichia coli ATCC 8739 and E. coli ATCC 25922) bacteria and yeasts of Candida albicans ATCC 10231. All produced composites showed biocidal activity against the bacteria. Composites containing {Ti₄O₂} cores and the {Ti₃O} core stabilized by the 4-hydroxybenzoic ligand showed also high activity against yeasts. The results of investigations carried out suggest that produced (PMMA + TOCs) composites, due to their microbiocidal activity, could find an application in the elimination of microbial contaminations in various fields of our lives. Full article

Microbial contamination remains a significant issue for many industrial, commercial, and medical applications. For instance, microbial surface contamination is detrimental to numerous aspects of food production, infection transfer, and even marine applications. As such, intense scientific interest has focused on improving the antimicrobial properties of surface coatings via both chemical and physical routes. However, there is a lack of synthetic coatings that possess long-term microbiocidal performance. In this study, silver nanoparticle cluster coatings were developed on copper surfaces via an ion-exchange and reduction reaction, followed by a silanization step. The durability of the microbiocidal activity for these develped surfaces was tested against pathogenic bacterial and fungal species, specifically Escherichia coli O157:H7 and Candida auris, over periods of 1- and 7-days. It was observed that more than 90% of E. coli and C. auris were found to be non-viable following the extended exposure times. This facile material fabrication presents as a new surface design for the production of durable microbicidal coatings which can be applied to numerous applications. Full article

The chemical vapor deposition (CVD) method has been used to produce dispersed silver nanoparticles (AgNPs) on the surface of titanium alloy (Ti6Al4V) and nanotubular modified titanium alloys (Ti6Al4V/TNT5), leading to the formation of Ti6Al4V/AgNPs and Ti6Al4V/TNT5/AgNPs systems with different contents of metallic silver particles. Their surface morphology and silver particles arrangement were characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), and atomic force microscopy (AFM). The wettability and surface free energy of these materials were investigated on the basis of contact angle measurements. The degree of silver ion release from the surface of the studied systems immersed in phosphate buffered saline solution (PBS) was estimated using inductively coupled plasma ionization mass spectrometry (ICP-MS). The biocompatibility of the analyzed materials was estimated based on the fibroblasts and osteoblasts adhesion and proliferation, while their microbiocidal properties were determined against Gram-positive and Gram-negative bacteria, and yeasts. The results of our works proved the high antimicrobial activity and biocompatibility of all the studied systems. Among them, Ti6Al4V/TNT5/0.6AgNPs contained the lowest amount of AgNPs, but still revealed optimal biointegration properties and high biocidal properties. This is the biomaterial that possesses the desired biological properties, in which the potential toxicity is minimized by minimizing the number of silver nanoparticles. Full article

This study set out to investigate the biological activity of monomeric surfactants dodecyltrimethylammonium bromide (DTAB) and the next generation gemini surfactant hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C6) against the environmental strain Pseudomonas aeruginosa PB_1. Minimal inhibitory concentrations (MIC) were determined using the dilution method. The viability of the planktonic cells and biofilm was assessed using the plate count method. Enzymatic profile was determined using the API-ZYM system. Proteins were extracted from the biofilm and planktonic cells and analysed using SDS-PAGE. The MIC of the gemini surfactants was 70 times lower than that of its monomeric analogue. After 4 h of treatment at MIC (0.0145 mM for C6 and 1.013 mM for DTAB), the number of viable planktonic cells was reduce by less than 3 logarithm units. At the concentration ≥MIC, a reduction in the number of viable cells was observed in mature biofilms (p < 0.05). Treatment for 4 h with gemini surfactant at 20 MIC caused complete biofilm eradication. At sub-MIC, the concentration of some enzymes reduced and their protein profiles changed. The results of this study show that due to its superior antibacterial activity, gemini compound C6 can be applied as an effective microbiocide against P. aeruginosa in both planktonic and biofilm forms. Full article

We investigated the biological activity of surfactants based on quaternary ammonium compounds: gemini surfactant hexamethylene-1,6-bis-(N,N-dimethyl-N-dodecylammonium bromide) (C6), synthesized by the reaction of N,N-dimethyl-N-dodecylamine with 1,6-dibromohexane, and its monomeric analogue dodecyltrimethylammonium bromide (DTAB). The experiments were performed with bacteria Asaia lannensis, a common spoilage in the beverage industry. The minimal inhibitory concentration (MIC) values were determined using the tube standard two-fold dilution method. The growth and adhesive properties of bacterial cells were studied in different culture media, and the cell viability was evaluated using plate count method. Both of the surfactants were effective against the bacterial strain, but the MIC of gemini compound was significantly lower. Both C6 and DTAB exhibited anti-adhesive abilities. Treatment with surfactants at or below MIC value decreased the number of bacterial cells that were able to form biofilm, however, the gemini surfactant was more effective. The used surfactants were also found to be able to eradicate mature biofilms. After 4 h of treatment with C6 surfactant at concentration 10 MIC, the number of bacterial cells was reduced by 91.8%. The results of this study suggest that the antibacterial activity of the gemini compound could make it an effective microbiocide against the spoilage bacteria Asaia sp. in both planktonic and biofilm stages. Full article

Quaternary ammonium compounds (QACs) are a group of compounds of great economic significance. They are widely used as emulsifiers, detergents, solubilizers and corrosion inhibitors in household and industrial products. Due to their excellent antimicrobial activity QACs have also gained a special meaning as antimicrobials in hospitals, agriculture and the food industry. The main representatives of the microbiocidal QACs are the benzalkonium chlorides (BACs), which exhibit biocidal activity against most bacteria, fungi, algae and some viruses. However, the misuses of QACs, mainly at sublethal concentrations, can lead to an increasing resistance of microorganisms. One of the ways to avoid this serious problem is the introduction and use of new biocides with modified structures instead of the biocides applied so far. Therefore new BAC analogues P13–P18 with pyridine rings were synthesized. The new compounds were characterized by NMR, FT-IR and ESI-MS methods. PM3 semiempirical calculations of molecular structures and the heats of formation of compounds P13–P18 were also performed. Critical micellization concentrations (CMCs) were determined to characterize the aggregation behavior of the new BAC analogues. The antimicrobial properties of novel QACs were examined by determining their minimal inhibitory concentration (MIC) values against the fungi Aspergillus niger, Candida albicans, Penicillium chrysogenum and bacteria Staphylococcus aureus, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa. The MIC values of N,N-dimethyl-N-(4-methylpyridyl)-N-alkylammonium chlorides for fungi range from 0.1 to 12 mM and for bacteria, they range from 0.02 to 6 mM. Full article

The aim of this study was to select effective and safe microbiocides for the disinfection and protection of historical wooden surfaces at the former Auschwitz II-Birkenau concentration and extermination camp. We tested seven active compounds against bacteria and moulds, of which didecyldimethylammonium chloride and N-(3-aminopropyl)-N-dodecylpropane-1,3-diamine were effective even at 0.02%–2%. Subsequently, eight microbiocides containing the selected active ingredients were chosen and applied three times on the surface of wood samples colonized by bacteria and moulds. ABM-1 and ABM-2—6% solution; Rocima 101—8%; Preventol R 80—12%; Acticide 706 LV—15% and Boramon—30% were the most effective disinfectants. Under laboratory conditions, ABM-1, Boramon and Rocima 101 ensured antimicrobial protection of new wood samples for six months. In situ, 30% Boramon and 8% Rocima 101 applied by spraying effectively protected the historical wood from bacterial and mould growth for 12 and 3 months, respectively. Colour and luminance of the new wood were not altered after exposure to the biocides. Boramon and Rocima 101, applied by the spraying method, caused no significant change in the colour of the historical wood. Results from this study were used to develop a procedure for the protection of wood in historical buildings against biodeterioration. Full article

The emerging problems posed by antibiotic resistance complicate the treatment regime required for wound infections and are driving the need to develop more effective methods of wound management. There is growing interest in the use of alternative, broad spectrum, pre-antibiotic antimicrobial agents such as essential oils (e.g., tea tree oil, TTO) and metal ions (e.g., silver, Ag⁺). Both TTO and Ag⁺ have broad spectrum antimicrobial activity and act on multiple target sites, hence reducing the likelihood of developing resistance. Combining such agents with responsive, controlled release delivery systems such as hydrogels may enhance microbiocidal activity and promote wound healing. The advantages of using chitosan to formulate the hydrogels include its biocompatible, mucoadhesive and controlled release properties. In this study, hydrogels loaded with TTO and Ag⁺ exhibited antimicrobial activity against P. aeruginosa, S. aureus and C. albicans. Combining TTO and Ag⁺ into the hydrogel further improved antimicrobial activity by lowering the effective concentrations required, respectively. This has obvious advantages for reducing the potential toxic effects on the healthy tissues surrounding the wound. These studies highlight the feasibility of delivering lower effective concentrations of antimicrobial agents such as TTO and Ag⁺ in ionically crosslinked chitosan hydrogels to treat common wound-infecting pathogens. Full article