Effect of Microfluidization on the Volatiles and Antibacterial, Antifungal, and Cytotoxic Activities of Algerian Satureja hortensis L. Oil-Loaded Nanoemulsions: In Vitro and In Silico Study.

This study aimed to increase the stability and solubility of the Algerian Satureja hortensis L. (ASHO) essential oil through nanoencapsulation. Nanoemulsions of ASHO (MF-ASHEO) were developed to evaluate their antioxidant and antimicrobial potential, stability, and cytotoxicity using microfluidization at 150 MPa for five cycles. MF-ASHO showed 8 compounds (99.56%) vs ASHEO's 26 compounds (95.46%). Carvacrol increased to 94.51%, replacing γ-terpinene, which decreased to 0.43%. The MF-ASHEO nanoemulsion had a mean particle size of 41.72 nm, a monomodal size distribution pattern, a mean ζ-potential of -39.4 mV, and a polydispersity index (PDI) mean value of 0.291. Micrographs showed spherical nanoparticles with varying diameters in nm. ASHEO was more toxic than MF-ASHEO against HepG2, Vero, and WI-38, according to the MTT and WST-1 assays. ASHEO demonstrated antiradical and antibacterial activity and inhibited biofilm formation. It also had an enhanced antifungal effect and reduced mycotoxin production. The MF-ASHEO sample showed no activity except in reducing mycotoxin production, where it performed better than ASHEO. In silico and ADME results confirmed the inhibitory action of carvacrol on the key enzymes of the aflatoxin biosynthetic mechanism and the target proteins associated with bactericidal/bacteriostatic effects. The microfluidization process dramatically affects not only the oil's volatile content but also its biological activity.

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.

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.

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

The emergence of multidrug-resistant (MDR) bacteria is a danger to public health and exposes patients to high risk, increasing morbidity and mortality worldwide. For this purpose, three months of evaluation of MDR's prevalence and antimicrobial susceptibility patterns in the military regional university hospital of Constantine from different services and samples was carried out. Among a total of 196 isolates, 35.2% were MDR. The use of essential oils such as Origanum glandulosum Desf. as an alternative to antibiotics is attractive due to their rich content of bioactive compounds conferring many biological activities. Also, to overcome the drawbacks of using oils as the hydrophobicity and negative interaction with the environmental conditions, in addition to increasing their activity, encapsulation for the oil was performed using high-speed homogenization (HSH) into nanocapsules and high-pressure homogenization (HPH) into nanoemulsion. Nine volatile constituents were determined using gas chromatography-mass spectrometry analysis (GC-MS) in hydrodistilled oil with thymol, carvacrol, p-cymene, and γ-terpinene as dominants. A dramatic decrease in the major volatile components was observed due to the use of HSH and HPH but generated the same oil profile. The mean particle size of the nanoemulsion was 54.24 nm, while that of nanocapsules was 120.60 nm. The antibacterial activity of the oil and its nanoparticles was estimated on MDR isolates using the disk diffusion, aromatogram, and broth microdilution methods. Consistent with the differences in volatile constituents, the oil exhibited a higher antibacterial activity compared to its nanoforms with the diameters of the inhibition zone against E. coli (20 mm), S. aureus (35 mm), and A. baumannii (40 mm). Both formulations have shown relatively significant activity against the biofilm state at sub-inhibitory concentrations, where nanoemulsion was more potent than nanocapsules. The results obtained suggested that nanoformulations of essential oils are strongly recommended for therapeutic application as alternatives to antibiotics.

Influence of Nanoencapsulation Using High-Pressure Homogenization on the Volatile Constituents and Anticancer and Antioxidant Activities of Algerian Saccocalyx satureioides Coss. et Durieu.

The nanoencapsulation of essential oils enhances their applicability in several areas, such as pharmaceuticals and food biopreservation. This study focuses on the encapsulation of Saccocalyx satureioides Coss. et Durieu essential oil into nanoemulsions by high-pressure homogenization (HPH) and its effect on the volatile constituents and the antioxidant and anticancer activities of the essential oil. The analysis of hydrodistilled (HD) S. satureioides essential oil using gas chromatography-mass spectrometry revealed a total of 28 constituents, representing 99.80%, while only 13 constituents were identified in nanoemulsions, representing 98.65% of the total volatile material. The use of HPH led to qualitative and quantitative differences between the volatile profiles of the HD and the nanoemulsion of S. satureioides essential oil. Whereas borneol, α-terpineol, and thymol were the predominant constituents in the HD oil, carvacrol, thymol, and γ-terpinene were the major constituents in the nanoemulsion. The antioxidant activity of the S. satureioides essential oil nanoemulsion displayed was lower as compared to that of HD oil using DPPH free radical-scavenging, CUPRAC, and ABTS assays. This is consistent with the differences in total flavonoid, total phenolic, and volatiles detected in both HD oil and its nanoemulsion. Meanwhile, the cytotoxicity on liver cancer cells (Hep-G2) was stronger using nanoemulsions (106 µg/mL) than using HD oil (274.8 µg/mL).

Effect of nanoencapsulation on volatile constituents, and antioxidant and anticancer activities of Algerian Origanum glandulosum Desf. essential oil.

Nanoencapsulation is an attractive novel technique used for incorporating essential oils in food preparations and pharmaceutical formulae. This study investigated the effect of nanoencapsulation on the composition of volatile compounds, as well as the antioxidant and anticancer activities of hydrodistilled (HD) Origanum glandulosum Desf. Oil, which was encapsulated into nanocapsules via High Speed Homogenization (HSH) and into nanoemulsions through High Pressure Homogenization (HPH). Thirty-two volatile components were identified using Gas Chromatography-Mass Spectrometry analysis (GC-MS) in HD essential oil representing 99.04% of the total oil content. GC-MS analysis showed that the use of HPH to prepare nanoemulsions negatively affected the active compounds present in HD oil, particularly carvacrol and thymol, whereas the use of HSH led to significant quantitative differences in the composition of volatiles between HD oil and nanocapsules but generated the same profile. Consistent with the differences in total phenolics, total flavonoids, and volatiles identified in HD and nanoparticles, HD essential oil exhibited a higher antioxidant activity (IC50 4.22 mg/mL) than nanocapsules (IC50 57.51 mg/mL) and nanoemulsion (IC50 78.50 mg/mL), while nanocapsules showed the strongest cytotoxic effect on liver cancer cell line Hep-G2 (54.93 µg/mL) in comparison to HD oil (73.13 µg/mL) and nanoemulsions (131.6 µg/mL).

Frequency and susceptibility pattern of uropathogenic Enterobacteriaceae isolated from patients in Algiers, Algeria.

INTRODUCTION: The frequency of Enterobacteriaceae involved in urinary tract infections (UTI) has increased significantly since the early 1990s, particularly in at-risk facilities such as resuscitation, surgery, urology and nephrology. The objective of this study was to evaluate the antimicrobial susceptibility of Enterobacteriaceae causing urinary tract infections (UTIs)at the University Hospital Centre of Benimessous in Algiers. METHODOLOGY: The study was designed as a retrospective study (between January 1st 2010 and December 31st 2012) and a prospective study (between January 1standApril 30th 2013) on 13,611 urine samples. Antimicrobial resistance phenotyping was conducted on the bacterial isolates using disk-diffusion method. RESULTS: On 13,611 urine samples analysed, 1,790 (13.15%) fulfilled the criteria for urinary tract infection. Enterobacteriaceae were identified in 1,561 analysed samples (87%). Escherichia coli was the dominant uropathogen (66,15%) in both hospitalized and non-hospitalized patients. The other main detected Enterobacteriaceae members were Klebsiella pneumoniae (11,96%) and Proteus mirabilis (5,42%). Analysis of results showed also that women were more prone to UTI than men with sex ratio of 3.76(W/M). The susceptibilities of isolated Enterobacteriaceae to antibiotics revealed that they had acquired resistance to several classes, particularly toward ß-lactams. Resistance frequencies were relatively high to ampicillin and sulfomethoxasole, while being very low to aminoglycosides and furans. Results obtained revealed also that 7% of isolates where resistant to third generation cephalosporins by production of extended spectrum ß-lactamases (ESBL). CONCLUSIONS: The continuous monitoring of antibiotic resistance of uropathogenic Escherichia coli is crucial to guide the clinician to choose the best empiric treatment.