Effect of Nanoencapsulation on the Antimicrobial and Antibiofilm Activities of Algerian Origanum glandulosum Desf. against Multidrug-Resistant Clinical Isolates

Potential Application of Origanum majorana Stabilized Silver Nanoparticles for Coating of Urinary Catheter

Introduction

Urinary tract infections related to catheters are one of the most common urinary infections and can affect patient outcomes. Hence, coating urinary catheters is an important issue against several resistant bacterial pathogens that can form a resistant biofilm. This study examined the antibacterial and antibiofilm properties of the coated catheter with green silver nanoparticles (AgNPs) made from Origanum majorana.

Methods

Aloe Vera, Ocimum basilicum, Matricaria chamomilla, Foeniculum vulgare, Glycyrrhiza glabra, Origanum majorana, Urtica urens, Salvia Rosmarinus, and Salvia officinalis hydro-alcoholic extracts were prepared and tested for their antibacterial activities utilizing the agar well diffusion technique. Furthermore, O. majorana extract was tested against biofilm formation using a microtiter plate assay. UPLC-ESI-Q-TOF was used for the profiling and tentative identification of biological compounds in the O. majorana extract. O. majorana was used to prepare AgNPs-MARJ, which were characterized for their size, charge, and shape. Further, AgNPs-MARJ were used to coat two types of urinary catheters. The coated catheters were tested for their resistance to bacterial biofilm formation and compared with non-coated catheters.

Results and Discussion

Initial antimicrobial screening tests showed that O. majorana extracts presented a significant (p<0.05; ANOVA/Tukey) antibacterial activity against the studied species of bacteria compared to the other plant extracts. O. majorana extract showed MIC value of 35.0 mg/mL for E. coli, Pseudomonas aeruginosa and K. pneumoniae and displayed the highest antibiofilm activity at 100 mg/mL. LC-MS analysis tentatively identified the presence of quinic acid and flavonoid-based constituents like apigenin which contribute to the antibiofilm activity. AgNPs-MARJ were efficiently prepared with a size and charge of 111.5 nm and -19.66 mV, respectively. The coated urinary catheters showed a significant (p<0.05) decrease in Pseudomonas aeruginosa biofilm formation compared to control non-coated catheters.

Conclusion

AgNPs-MARJ offer promising prospects for addressing biofilm-related challenges in urinary tract-related catheter infections.

Investigating the Therapeutic Effects of Albendazole, Mebendazole, and Praziquantel Nanocapsules in Hydatid Cyst-Infected Mice

Drug resistance is the main challenge in treating parasitic diseases, including cystic echinococcosis (CE). Hence, the current study aims to investigate the effect of nanocapsules containing albendazole (ABZ), mebendazole (MBZ), and praziquantel (PZQ) on treating hydatid cysts in mice using these high-potency drugs. A total of 78 female white laboratory mice (BALB/C mice), 8 weeks old and weighing 25 g, were intraperitoneally injected with 1500 live protoscoleces of Echinococcus granulosus. The first group received ABZ nanocapsules, group 2 received MBZ nanocapsules, group 3 received PZQ nanocapsules, group 4 received ABZ + MBZ nanocapsules, group 5 received ABZ + PZQ nanocapsules, and group 6 received MBZ + PZQ nanocapsules. Each group also had a control group, which received the non-nanocapsulated drugs (group 7-12). Group 13 received no treatment and served as the negative control, just receiving phosphate-buffered saline (PBS). A thorough examination of the cysts' physical properties, including size, quantity, and weight, was carried out. According to our results, the polymeric nanocapsules are sphere-like and of different sizes. The total number of cysts in all nanocapsule groups significantly decreased compared to the control group. In the total weight of the cysts, ABZ + MBZ nanocapsules, ABZ + PZQ nanocapsules, and MBZ + PZQ nanocapsules had the least total cyst weight, showing that the use of the medicinal combination had a better effect on the penetration and weight reduction of the cysts. In conclusion, the findings showed that ABZ, MBZ, and PZQ significantly reduced the size, weight, and number of hydatid cysts in the mouse model used in this study.

Nanoemulsions of essential oils against multi-resistant microorganisms: An integrative review

Microbial resistance to drugs continues to be a global public health issue that demands substantial investment in research and development of new antimicrobial agents. Essential oils (EO) have demonstrated satisfactory and safe antimicrobial action, being used in pharmaceutical, cosmetic, and food formulations. In order to improve solubility, availability, and biological action, EO have been converted into nanoemulsions (NE). This review identified scientific evidence corroborating the antimicrobial action of nanoemulsions of essential oils (NEEO) against antibiotic-resistant pathogens. Using integrative review methodology, eleven scientific articles evaluating the antibacterial or antifungal assessment of NEEO were selected. The synthesis of evidence indicates that NEEO are effective in combating multidrug-resistant microorganisms and in the formation of their biofilms. Factors such as NE droplet size, chemical composition of essential oils, and the association of NE with antibiotics are discussed. Furthermore, NEEO showed satisfactory results in vitro and in vivo evaluations against resistant clinical isolates, making them promising for the development of new antimicrobial and antivirulence drugs.

Synthesis of Berberis aristate rhizome extract stabilized magnesium nanoparticles using green chemistry: rhizome characterization, in vitro antimicrobial and anti-inflammatory activity

In the present study, magnesium nanoparticles (Mg NPs) were synthesized utilizing an aqueous extract of Berberis aristate rhizome and evaluated for antimicrobial and anti-inflammatory activity. Technofunctional properties of rhizome powder were evaluated and during thermal stability evaluation four stages of decomposition with a maximum delta Y value of 76.04 % was observed. Optimization of Mg NPs was carried out by employing eight different concentrations (C1-C8)   and the C4 showed maximum absorbance at 330 nm confirming the NPs synthesis. The Mg NPs showed the particle size of 62 nm, zeta potential of -24.7 mV and hexagonal mprphology. Potential inhibition against S. aureus and E. coli (76.78 ± 0.05% and 74.62 ± 0.17%)and anti-inflammatory activity ranging from 42.43 ± 0.07-82.92 ± 0.04% was observed for Mg NPs. Therefore, green synthesis of Mg NPs is a promising approach for the development ofbiological active NPs to cure microbial infections.

Characterization and Determination of the Antibacterial Activity of Baccharis dracunculifolia Essential-Oil Nanoemulsions

The aim of this study was to evaluate the antibacterial activity of nanoemulsions of Baccharis dracunculifolia essential oil. The volatile compounds of the essential oil were identified using gas chromatography-mass spectrometry. The properties of the nanoemulsions (droplet size, polydispersity index, pH, and electrical conductivity) were determined. The antibacterial activities of the essential oil and its nanoemulsions were evaluated using MIC, MBC, and disk diffusion. The microorganisms used were: Gram-positive bacteria (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 14579, Streptococcus mutans ATCC 25175, and Enterococcus faecalis ATCC 29212) and Gram-negative bacteria (Pseudomonas aeruginosa ATCC 27853, Klebsiella pneumoniae ATCC BAA-1706, Salmonella enterica ATCC 14028, and Escherichia coli ATCC 25922). The major volatile compounds of the B. dracunculifolia essential oil were limonene (19.36%), (E)-nerolidol (12.75%), bicyclogermacrene (10.76%), and β-pinene (9.60%). The nanoemulsions had a mean droplet size between 13.14 and 56.84 nm. The nanoemulsions presented lower and statistically significant MIC values compared to the essential oil, indicating enhancement of the bacteriostatic action. The disk diffusion method showed that both the nanoemulsions and the essential oil presented inhibition zones only for Gram-positive bacteria, while there were no results against Gram-negative bacteria, indicating that B. dracunculifolia essential oil has a better antimicrobial effect on Gram-positive microorganisms.

Effect of nano-encapsulated food flavorings on streptozotocin-induced diabetic rats

Flavors and aromas are widely used in food and pharmaceutical industries to enhance food palatability. However, it is worth noting that they may also have bioactivity. This study aims to examine the potential impact of key flavors and their nanocapsules on health and diseases, such as type 2 diabetes mellitus (T2DM). The 36 nanocapsules of key flavorings were prepared by high shear homogenization (HSH). Seventy-two male Sprague-Dawley rats received a single dosage of streptozotocin (35 mg kg-1 body weight) intraperitoneally. All of the nutritional and biochemical parameters were statistically analyzed. A virtual docking study was conducted. Linalool nanoemulsion results showed the highest encapsulation efficiency (86.76%), while isoamyl acetate nanoparticles showed the lowest (69.99%). According to GC-MS analysis, encapsulation did not affect the flavoring structure with particle size distributions ranging from 277.3 to 628.8 nm. Using TEM, nanoemulsion particles appeared spherical with a desired nanometric diameter size. In the oral glucose tolerance test, flavorings in oil and nanoforms had no discernible hypoglycemia effects in normal rats. The nutritional and biochemical parameters confirmed that both normal and nanoencapsulation forms demonstrated a potential anti-hyperglycemic effect, and enhanced the rat health compared to the raw flavorings. The studied flavorings and their nanocapsules seem to have the potential double effect of a flavor compound as a food palatability enhancer with a potential beneficial effect on type 2 diabetes mellitus without any health drawbacks.

Evaluation of In Vitro Antimicrobial, Antioxidant, and Anti-Quorum Sensing Activity of Edible Mushroom (Agrocybe aegerita)

In the present study, ethanol extract obtained from the mycelial culture of Agrocybe aegerita was evaluated for its antioxidant activity as well for its potential to inhibit the virulence factor responsible for quorum-sensing activity and antibiofilm activity of pathogenic Pseudomonas aeruginosa PAO1 strain. The extract of mushroom at different concentrations showed percentage inhibition in a dose-dependent manner for DPPH and nitric oxide assays with the lowest as 38.56 ± 0.11% and 38.87 ± 0.04% at 50 µg/mL and the highest as 85.63 ± 0.12% and 82.34 ± 0.12% at 200 µg/mL. FTIR analysis confirmed the presence of functional group -OH, O-H bending bonds, C=C stretching, pyranose ring, and H-C-H stretch, confirming the presence of phenol, carotenoid, and ascorbic acid. HPLC analysis revealed that the concentration of gallic acid present in the extract is 27.94 mg/100 g which is significantly (p < 0.05) more than the concentration of rutin (i.e., 7.35 mg/100 g). GC-MS analysis revealed the presence of 5-methyl-1-heptanol, 2-heptadecenal, phthalic acid, butyl hept-4-yl ester, 2-dodecanol, benzoic acid, TMS derivative. The extract showed significantly (p < 0.05) more inhibition of pyocyanin (61.32%) and pyoverdine (54.02%). At higher concentrations of mushroom extract, there was a significant (p < 0.05) reduction (56.32%) in the swarming motility of the test organism. The extract showed 72.35% inhibition in biofilm formation. Therefore, it has been concluded from the present study that mushroom extract, which is rich in phenolic compounds interferes with the virulence factor responsible for quorum sensing, thereby inhibiting biofilm formation, and can be utilized as therapeutic agents against multi-drug resistant pathogenic microorganisms.

Green extraction of Milletia pinnata oil for the development, and characterization of pectin crosslinked carboxymethyl cellulose/guar gum herbal nano hydrogel

Milletia pinnata oil and Nardostachys jatamansi are rich sources of bioactive compounds and have been utilized to formulate various herbal formulations, however, due to certain environmental conditions, pure extract form is prone to degradation. Therefore, in this, study, a green hydrodistillation technology was used to extract M. pinnata oil and N. jatamansi root for the further application in development of pectin crosslinked carboxymethyl cellulose/guar-gum nano hydrogel. Both oil and extract revealed the presence of spirojatamol and hexadecanoic acid methyl ester. Varied concentrations (w/w) of cross-linker and gelling agent were used to formulate oil emulsion extract gel (OEEG1, OEG1, OEEG2, OEG2, OEEG3, OEG3, OEEG4, OEG4, OEEG5, OEG5), in which OEEG2 and OEG2 were found to be stable. The hydrogel displayed an average droplet size of 186.7 nm and a zeta potential of -20.5 mV. Endo and exothermic peaks and the key functional groups including hydroxyl, amide II, and amide III groups confirmed thermal stability and molecular structure. The smooth surface confirmed structural uniformity. Bactericidal activity against both Gram-positive (25.41 ± 0.09 mm) and Gram-negative (27.25 ± 0.01 mm) bacteria and anti-inflammatory activity (49.25%-83.47%) makes nanohydrogel a potential option for treating various infections caused by pathogenic microorganisms. In conclusion, the use of green hydrodistillation technology can be used to extract the bioactive compounds that can be used in formulation of biocompatible and hydrophobic nanohydrogels. Their ability to absorb target-specific drugs makes them a potential option for treating various infections caused by pathogenic microorganisms.

Development of Nanotechnology-Based Drug Delivery Systems for Controlling Clinical Multidrug-Resistant Staphylococcus aureus and Escherichia coli Associated with Aerobic Vaginitis

The growing prevalence of resistance to antibiotics potentially makes Escherichia coli and Staphylococcus aureus serious pathogens, necessitating the development of new antimicrobial agents. We extracted crude biosurfactants from a potential probiotic Bacillus spp. to control pathogenic bacteria associated with aerobic vaginal infection. Using nanotechnology formulations, we developed nanoemulsions based on biosurfactants at different concentrations (1% and 3.33%). The results showed that these nanoemulsions were stable, with a weighted index of 0.3, and demonstrated broad-spectrum antibacterial activity against Escherichia coli and Staphylococcus aureus, with MICs ranging between 1.25 and 4 mg/mL. Additionally, the nanoemulsions exhibited interesting antibiofilm effects. All strains became more sensitive to the antibiotics to which they were resistant because of various biosurfactant formulations combined with antibiotics. Lower concentrations of BNE1% and 3.33% were still more efficient than the crude biosurfactants. Our findings demonstrated that the biosurfactant had a strong antibiofilm effect against all tested pathogens. This antibacterial effect can be explained by their ability to alter cell physiology such as cell hydrophobicity and membrane disintegration. Thus, we can conclude that the use of nanotechnology formulations has improved this effect, and the nanoemulsions developed in this study can be used as a potential anti-infectious therapy against multidrug-resistant bacterial strains of clinical origin.

Microfluidizing Technique Application for Algerian Cymbopogon citratus (DC.) Stapf Effects Enhanced Volatile Content, Antimicrobial, and Anti-Mycotoxigenic Properties

Medicinal plant extracts are a promising source of bioactive minor contents. The present study aimed to evaluate the distinguished volatile content of Algerian Cymbopogon citratus (DC.) Stapf before and after the microfluidization process and their related antimicrobial and anti-mycotoxigenic impacts and changes. The GC-MS apparatus was utilized for a comparative examination of Algerian lemongrass essential oil (LGEO) with its microfluidization nanoemulsion (MF-LGEO) volatile content. The MF-LGEO was characterized using Zetasizer and an electron microscope. Cytotoxicity, antibacterial, and antifungal activities were determined for the LGEO and MF-LGEO. The result reflected changes in the content of volatiles for the MF-LGEO. The microfluidizing process enhanced the presence of compounds known for their exceptional antifungal and antibacterial properties in MF-LGEO, namely, neral, geranial, and carvacrol. However, certain terpenes, such as camphor and citronellal, were absent, while decanal, not found in the raw LGEO, was detected. The droplet diameter was 20.76 ± 0.36 nm, and the polydispersity index (PDI) was 0.179 ± 0.03. In cytotoxicity studies, LGEO showed higher activity against the HepG2 cell line than MF-LGEO. Antibacterial LGEO activity against Gram-positive bacteria recorded an inhibitory zone from 41.82 ± 2.84 mm to 58.74 ± 2.64 mm, while the zone ranged from 12.71 ± 1.38 mm to 16.54 ± 1.42 mm for Gram-negative bacteria. Antibacterial activity was enhanced to be up to 71.43 ± 2.54 nm and 31.54 ± 1.01 nm for MF-LGEO impact against Gram-positive and Gram-negative pathogens. The antifungal effect was considerable, particularly against Fusarium fungi. It reached 17.56 ± 1.01 mm and 13.04 ± 1.37 mm for LGEO and MF-LGEO application of a well-diffusion assay, respectively. The MF-LGEO was more promising in reducing mycotoxin production in simulated fungal growth media due to the changes linked to essential compounds content. The reduction ratio was 54.3% and 74.57% for total aflatoxins (AFs) and ochratoxin A (OCA) contents, respectively. These results reflect the microfluidizing improvement impact regarding the LGEO antibacterial, antifungal and anti-mycotoxigenic properties.

Gum arabic/guar gum stabilized Hydnocarpus wightiana oil nanohydrogel: Characterization, antimicrobial, anti-inflammatory, and anti-biofilm activities

Hydnocarpus wightiana oil has proven to inhibit the growth of pathogenic microorganisms; however, the raw form is highly susceptible to oxidation, and thus it becomes toxic when uptake is in high amounts. Therefore, to minimize the deterioration, we formulated Hydnocarpus wightiana oil-based nanohydrogel and studied its characteristics as well biological activity. The low energy-assisted hydrogel was formulated by including gelling agent, connective linker, and cross-linker and it resulted in internal micellar polymerization of the milky white emulsion. The oil showed the presence of octanoic acid, n-tetradecane, methyl 11-(2-cyclopenten-1-yl) undecanoate (methyl hydnocarpate), 13-(2-cyclopenten-1-yl) tridecanoic acid (methyl chaulmoograte), and 10,13-eicosadienoic acid. The amount of caffeic acid was 0.0636 mg/g, which was higher than the amount of gallic acid (0.0076 mg/g) in the samples. The formulated nanohydrogel showed an average droplet size of 103.6 nm with a surface charge of -17.6 mV. The minimal inhibitory bactericidal, and fungicidal concentrations of nanohydrogel against pathogenic bacteria and fungi were ranging from 0.78 to 1.56 μl/mL with 70.29-83.62 % antibiofilm activity. Also, nanohydrogel showed a significantly (p < 0.05) higher killing rate for Escherichia coli (7.89 log CFU/mL) than Staphylococcus aureus (7.81 log CFU/mL) with comparable anti-inflammatory activity than commercial standard (49.28-84.56 %). Therefore, it can be concluded that being hydrophobic, and having the capability of target-specific drug absorption as well as biocompatibility nanohydrogels can be utilized to cure various pathogenic microbial infections.

Origanum vulgare ethanolic extracts as a promising source of compounds with antimicrobial, anti-biofilm, and anti-virulence activity against dental plaque bacteria

Dental caries and periodontal diseases remain a challenge for oral health, especially given the lack of effective and safe treatment options that are currently available. Against the backdrop of an ongoing antimicrobial resistance crisis, a renewed interest in traditional medicinal plants as a potential source of new bioactive compounds has surfaced. In this context, we systematically screened the antimicrobial and anti-biofilm activities of both ethanolic and aqueous extracts of nine Algerian medicinal plants (Artemisia herba alba, Centaurium erythraea, Juglans regia, Laurus nobilis, Matricaria recutita, Mentha pulegium, Mentha piperita, Origanum vulgare and Taraxacum officinale). To evaluate the activity spectrum of the extracts, the screening was carried out against an extensive collection of Streptococcus, Enterococcus and Lacticaseibacillus isolates recovered from dental plaques of Algerian patients. Broad-spectrum antimicrobial and anti-biofilm properties were observed, especially among ethanolic extracts, which marks them as a promising source for bioactive compounds to control oral biofilms. The ethanolic extract of O. vulgare, which showed the most promising effects in the initial screening, was further characterized. We first verified the biocompatibility of this extract using human oral keratinocytes and selected a range of non-cytotoxic concentrations (0.195-0.781 mg/ml) to further validate its anti-biofilm and anti-virulence potential. At these concentrations, the extract not only prevented biofilm formation (10.04 ± 0.75-87.91 ± 9.08% of reduction) of most dental plaque isolates on a polystyrene surface, but also significantly reduced their adherence to hydroxyapatite (34.58 ± 9.09-62.77 ± 0.95%). Moreover, the extract showed curative potential against mature biofilms grown under conditions mimicking the oral niche. In addition to its anti-biofilm properties, we observed an inhibition of glucosyltransferase activity, a reduction in acidogenesis and a downregulation in the expression of multiple virulence-associated genes for extract-treated samples. Since anti-virulence properties are more robust to the development of resistance, they provide an attractive complementation to the antimicrobial activities of the extract. Thymol was identified as an important active compound of the extract using GC-MS analysis, but synergy with other compounds was also detected, suggesting a potential advantage of using the whole extract over purified thymol. Further research into the bioactive compounds of the O. vulgare ethanolic extract could yield novel products to fight dental caries.

In Silico Study for Algerian Essential Oils as Antimicrobial Agents against Multidrug-Resistant Bacteria Isolated from Pus Samples

In the context of the globally growing problem of resistance to most used antibacterial agents, essential oils offer promising solutions against multidrug-resistant (MDR) bacterial pathogens. The present study aimed to evaluate the prevalence, etiology, and antibiotic-resistance profiles of bacteria responsible for pyogenic infections in Regional Military University Hospital of Constantine. Disc diffusion and broth microdilution (MIC) methods were used to evaluate the antimicrobial activity of essential oils from five Algerian aromatic plants growing wild in the north of Algeria-Salvia officinalis (Sage), Thymus vulgaris (Thyme), Mentha pulegium L. (Mentha), Rosmarinus officinalis (Rosemary), and Pelargonium roseum (Geranium)-against reference and MDR strains. During three months of the prospective study, 112 isolates out of 431 pus samples were identified. Staphylococcus aureus was the most predominant species (25%), followed by Klebsiella pneumoniae (21.42%), Pseudomonas aeruginosa (21%), and Escherichia coli (17.95%). Among pus isolates, 65 were MDR (58.03%). The radial streak-line assay showed that R. officinalis and M. pulegium L. had weak activity against the tested strains, whereas P. roseum showed no activity at all. Meanwhile, T. vulgaris was the most potent, with an inhibition zone of 12-26 mm and an MIC value ranging between 0.25 and 1.25%, followed by S. officinalis with an inhibition zone of 8-12 mm and an MIC value ranging between 0.62 and 2.5%. Generally, A. baumannii and S. aureus ATCC6538P were the most sensitive strains, whereas P. aeruginosa ATCC27853 was the most resistant strain to the oils. Gas chromatography-mass spectrometry analysis of chemical composition revealed the presence of borneol (76.42%) and thymol (17.69%) as predominant in thyme, whereas camphor (36.92%) and α- thujone (34.91%) were the major volatiles in sage. The in-silico study revealed that sesquiterpenes and thymol had the highest binding free energies against the vital enzymes involved in biosynthesis and repair of cell walls, proteins, and nucleic acids compared to monoterpenes. The results demonstrated that T. vulgaris and S. officinalis are ideal candidates for developing future potentially active remedies against MDR strains.