Minimum Bactericidal Concentration Values Research Articles

Efficacy Evaluation of Jania rubens Extract Against Four Pathogenic Strains Associated with Foodborne Disease in Iran

This study evaluated the antimicrobial properties of Jania rubens algae extract, obtained via Soxhlet extraction, against food spoilage and pathogenic bacteria. Using response surface methodology and the Box-Behnken design, the research optimized extraction parameters, including solvent type, solvent-to-algae ratio, and extraction duration. Antimicrobial efficacy was assessed through the zone of inhibition (ZOI), Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) against Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, and Bacillus cereus. Results showed MIC and MBC values for E. coli ranged from 0.32–1.5 and 2–3, respectively; for S. enteritidis, 0.98–1.9 and 2.5–3.5; for S. aureus, 0.4–1.5 and 0.8–2.8; and for B. cereus, 0.36–1.35 and 0.85–1.85. Optimal extraction conditions included acetone as the solvent, a 5:1 solvent-to-algae ratio, and extraction durations of 2 or 6 hours. The algae extract significantly extended the lag phase and reduced bacterial growth rates, with effects intensifying at higher concentrations. The study concludes that Jania rubens extract, particularly under optimized Soxhlet extraction conditions, exhibits potent antibacterial activity, making it a promising natural antimicrobial agent for food preservation.

Efficacy Evaluation of Jania rubens Extract Against Four Pathogenic Strains Associated with Foodborne Disease in Iran

This study evaluated the antimicrobial properties of Jania rubens algae extract, obtained via Soxhlet extraction, against food spoilage and pathogenic bacteria. Using response surface methodology and the Box-Behnken design, the research optimized extraction parameters, including solvent type, solvent-to-algae ratio, and extraction duration. Antimicrobial efficacy was assessed through the zone of inhibition (ZOI), Minimum Inhibitory Concentration (MIC), and Minimum Bactericidal Concentration (MBC) against Escherichia coli, Salmonella enteritidis, Staphylococcus aureus, and Bacillus cereus. Results showed MIC and MBC values for E. coli ranged from 0.32–1.5 and 2–3, respectively; for S. enteritidis, 0.98–1.9 and 2.5–3.5; for S. aureus, 0.4–1.5 and 0.8–2.8; and for B. cereus, 0.36–1.35 and 0.85–1.85. Optimal extraction conditions included acetone as the solvent, a 5:1 solvent-to-algae ratio, and extraction durations of 2 or 6 hours. The algae extract significantly extended the lag phase and reduced bacterial growth rates, with effects intensifying at higher concentrations. The study concludes that Jania rubens extract, particularly under optimized Soxhlet extraction conditions, exhibits potent antibacterial activity, making it a promising natural antimicrobial agent for food preservation.

Evaluation of Antioxidant, Xanthine Oxidase-Inhibitory, and Antibacterial Activity of Syzygium cumini Linn. Seed Extracts

Syzygium cumini (L.) Skeels, commonly known as the Jamun or Indian blackberry, is a tropical evergreen tree native to the Indian subcontinent, and it belongs to the Myrtaceae family. This research aimed to assess the antibacterial properties of the extracts derived from S. cumini seed kernels and evaluate their total flavonoid content, total phenol content, total carbohydrate content, antioxidant capacity, and inhibitory effects on xanthine oxidase. Cold maceration was chosen for its ability to preserve thermolabile compounds and efficiently extract bioactive constituents with minimal energy and equipment requirement, with hexane and methanol employed as extraction solvents. The methanolic seed kernel extract of S. cumini showed the highest flavonoid (127.78 μg quercetin equivalent/mg dried extract vs. 21.24 μg quercetin equivalent/mg in hexane dried extract) and polyphenol content (153.81 μg gallic acid equivalent/mg dried extract vs. 38.89 μg gallic acid equivalent/mg in hexane dried extract), along with significant carbohydrate content (475.61 μg glucose equivalent/mg dried extract vs. 5.57 μg GE/mg in hexane dried extract). It also demonstrated potent antioxidant activity (IC50: 9.23 μg/mL; ascorbic acid: 5.10 μg/mL) and xanthine oxidase inhibition (IC50: 14.88 μg/mL), comparable to the standard drug allopurinol (IC50: 6.54 μg/mL), suggesting its therapeutic potential. Moreover, the methanolic extract of seed kernels exhibited strong antibacterial activity, with inhibition zones of 19.00 mm against S. epidermidis, higher than the standard antibiotic (gentamicin: 18.33 mm) against K. pneumonia (ciprofloxacin: 33.66 mm). The lowest minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.32 mg/mL and 0.52 mg/mL, respectively, were observed for the same extract against S. epidermis. In conclusion, this study demonstrated the remarkable antibacterial effects of S. cumini methanolic seed kernel extract against various pathogenic microorganisms as well as significant inhibitory effects on xanthine oxidase and antioxidant activity.

Evaluation of the Synergistic Antimicrobial Activity of Essential Oils and Cecropin A Natural Peptide on Gram-Negative Bacteria.

In an era dominated by the phenomenon of antibiotic resistance, it is increasingly important to look for alternatives to synthetic antibiotics. In light of these considerations, the synergistic use of essential oils and Antimicrobial Peptides (AMPs) seems a viable strategy. In this study, we assessed the Minimum Inhibitory Concentration (MIC), Minimum Bactericidal Concentration (MBC) and Fractional Inhibitory Concentration (FIC) of three Essential Oils (EOs): winter savory (Satureja montana), bergamot (Citrus bergamia) and cinnamon (Cinnamomum zeylanicum) and of the insect antimicrobial peptide Cecropin A (CecA), alone and in combination with EOs, against two Gram-negative ATCC bacterial strains: Escherichia coli and Salmonella enterica serovar Typhimurium. The MIC results showed that winter savory EO (SmEO) and cinnamon EO (CzEO) exhibited the strongest antibacterial activity against both bacterial strains, whereas bergamot EO (CbEO) and CecA demonstrated comparatively lower antibacterial efficacy. These results were also confirmed by the MBC values. The FIC Indices (FICI) revealed that the most effective synergies were observed with the combinations SmEO/CzEO and SmEO/CbEO against E. coli, while against S. enterica Typhimurium the best combinations were CbEO/CzEO and SmEO/CzEO. Regarding CecA, although it was not the most efficient agent either individually or in combination, it is noteworthy that, when combined, it exhibited antibacterial activity even at a 1:64 dilution.

Biosynthesis and activity of Zn-MnO nanocomposite in vitro with molecular docking studies against multidrug resistance bacteria and inflammatory activators

This study investigated the green synthesis of Zn-MnO nanocomposites via the fungus Penicillium rubens. Herein, the synthesized Zn-MnO nanocomposites were confirmed by UV-spectrophotometry with a top peak (370 nm). Transmission electron microscopy confirmed irregular particles with a spherical-like shape ranging from 25.13 to 36.21 nm. Numerous functional groups were detected on the surface of Zn-MnO nanocomposite via Fourier-transform infrared spectroscopy. X-Ray diffraction assay appeared that the synthesized Zn-MnO nanocomposites contained two different components, MnO (JCPDS 81-2261) and ZnO (JCPDS 36-1451), while energy dispersive X-ray spectra confirmed the occurrence of manganese, zinc, oxygen, and carbon in Zn-MnO nanocomposites. Zn-MnO nanocomposites demonstrated excellent suppress effect versus the growth of various bacteria namely Staphylococcus aureus, Methicillin-resistant S. aureus (MRSA), Salmonella typhi, and Klebsiella pneumoniae via agar well diffusion assays with inhibition areas of 36 ± 0.1, 25 ± 0.1, 27 ± 0.2, and 23 ± 0.2 mm, correspondingly. Alterations in the ultrastructure of the treated K. pneumoniae by Zn-MnO nanocomposite were recorded. Both the values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration of Zn-MnO nanocomposite extended from 15.62 to 125 µg/mL employing the examined bacteria. The antibiofilm activity of Zn-MnO nanocomposites was 82.07, 75.43, 43.65, and 41.35% at 25% MIC, and 96.54, 93.0, 94.53, and 91.11% at 75% MIC against S. aureus, MRSA, K. pneumoniae, and S. typhi, respectively. At 25 to 75% MIC, Zn-MnO nanocomposites exhibited antihemolytic activity with the maximum activity of 96.3% at 75% MIC in the presence of MRSA. Extensive molecular docking studies were performed to identify the optimal location for manganese oxide and zinc oxide nanoclusters binding to MRSA. MnO-NPs and ZnO-NPs demonstrated inhibitory activity against the crystal structure of putative minohydrolase (PDB ID: 4EWT), methicillin acyl-penicillin binding protein 2a structure (PDB ID: 1MWU) and K2U bound crystal structure of class II peptide deformylase from MRSA (PDB ID: 6JFQ). The minimum binding energy was utilized to estimate the receptor’s binding site with NPs, providing additional understanding of the ways of action. Anti-inflammatory activity of Zn-MnO nanocomposites via cyclooxygenase-1 and cyclooxygenase-2 enzymes inhibition was documented with IC50 doses of 20.81 ± 0.68 µg/mL and 35.87 ± 1.35 µg/mL, respectively. Based on these outcomes, it was concluded that Zn-MnO nanocomposites could be useful agents for the management of multidrug resistant bacterial pathogens and inflammation.

Chemical Characterization and Antimicrobial Activity of Essential Oils and Nanoemulsions of Eugenia uniflora and Psidium guajava.

Background/Objectives: This study aimed to develop gel nanoemulsions (NEs) of Brazilian essential oils (EOs) from Eugenia uniflora and Psidium guajava, as well as to perform chemical characterization and investigate the antimicrobial activity of the EOs and NEs. Results/Conclusions: The main chemical compounds of E. uniflora EO were curzerene (34.80%) and germacrene B (11.92%), while those of P. guajava EO were β-caryophyllene (25.92%), β-selinene (22.64%), and γ-selinene (19.13%). The NEs of E. uniflora and P. guajava had droplet sizes of 105.30 and 99.50 nm and polydispersity index (PDI) values of 0.32 and 0.43, respectively. The NEs remained stable for 30 days of storage at 25 °C, with droplet sizes of 104.7 and 103.8 nm, PDI values below 0.50, and no phase separation. The NE of E. uniflora exhibited inhibition zones ranging from 8.41 to 15.13 mm against the Gram-positive bacterium Staphylococcus aureus and the Gram-negative bacteria Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii. Additionally, the NE of E. uniflora showed the largest inhibition zones against Candida albicans (20.97 mm) and Candida krusei (15.20 mm), along with low minimum inhibitory concentration (MIC) values (0.54-1.22 mg/mL) and minimal bactericidal concentration (MBC) values (4.84-11.02 mg/mL) against these pathogenic yeasts. The NE of P. guajava demonstrated low MIC (1.26 mg/mL) and MBC (11.35 mg/mL) values for C. krusei. The time-growth inhibition assay also suggests the effectiveness of the NE against the tested pathogens S. aureus and E. coli, highlighting its potential as a novel alternative therapeutic agent.

Fabrication and characterization of chitosan-based bionanocomposite coating reinforced with TiO2 nanoparticles and carbon quantum dots for enhanced antimicrobial efficacy.

Polymer-based nanocomposite coatings that are enhanced with nanoparticles have gained recognition as effective materials for antibacterial purposes, providing improved durability and biocidal effectiveness. This research introduces an innovative chitosan-based polymer nanocomposite, enhanced with titanium oxide nanopowders and carbon quantum dots. The material was synthesized via the sol-gel process and applied to 316L stainless steel through dip-coating. Structural and morphological properties, including crystal structure, microstructure, elemental dispersion, particle size distribution, chemical composition, and surface morphology, were thoroughly characterized. The results demonstrated that carbon quantum dots and titanium oxide nanopowders were uniformly dispersed within the chitosan matrix, forming a homogeneous, non-agglomerated coating. The antibacterial efficacy of the synthesized samples against 7 different Gram-positive and Gram-negative bacteria was assessed through disk diffusion, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) tests. The results confirmed the antibacterial activity of synthesized samples against most of the bacterial pathogens tested but exhibited stronger antibacterial effects on Gram-negative bacteria compared to Gram-positive bacteria. The largest inhibition zones, measuring 21 mm and 16 mm, were observed for Pseudomonas and E. coli for titanium dioxide nanoparticles and the final nanocomposite, respectively. Additionally, the MIC and MBC values for all 7 bacteria were determined.

Nitrogen stress-induced modulation of antimicrobial and antioxidant activities in Aphanothece sp.: Insights from phytochemical profiling and molecular docking

The modulation of nutrient availability represents a critical factor influencing the metabolic pathways and production of bioactive compounds in algae. This study aimed to examine the impact of nitrogen stress on the antimicrobial and antioxidant properties, phytochemical composition, and molecular docking assessments of the cyanobacterium Aphanothece sp. The results demonstrated that Aphanothece sp. when cultivated under conditions of nitrogen deficiency, exhibited markedly elevated antimicrobial and antioxidant activity compared to the control. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of the extracts obtained from algae on E. coli ATCC 25922 were found to be 25 mg mL−1 when the sample was grown in nitrogen medium and 6.25 mg mL−1 when grown in a nitrogen-free medium. The IC50 value obtained from DPPH free radical scavenging assay changed from 137.30 ± 16.22 mg mL−1 to 20.07 ± 1.55 mg mL−1 in nitrogen-free medium. According to the results of GC–MS analysis, the major components in the extract obtained from the algae grown in the nitrogen-free environment were 13,16-Octadecadiynoic acid, methyl ester (35.10 %) and Hexadecanoic acid, methyl ester (22.65 %), while the major components in the extract obtained from the algae grown in nitrogen-containing medium were Protopine (65.68 %) and 3,6,9,12,15-Pentaoxabicyclo(15.3.1)henicosa-1(21),17,19-triene-2,16-dione (12.15 %). The findings suggest a range of binding energies and interaction profiles for the compounds in the extracts with their molecular targets, which may have implications for their potential significance in therapeutic applications. The results of this study indicate that nitrogen stress can be employed as a strategic tool to enhance the production of valuable bioactive compounds in Aphanothece sp., thereby underscoring its potential applications in biotechnology and drug development.

GC-MS PROFILING AND In vitro ANTIBACTERIAL EFFICACY OF AQUEOUS LEAF EXTRACTS OF Ocimum gratissimum Linn. AND Vernonia amygdalina Del

The increasing spread, persistence, and prevalence of multidrug-resistant bacterial strains has become a significant global public health challenge, necessitating the need for novel, potent, and alternative antimicrobial agents, particularly from medicinal plants. The study determined the bioactive phytochemical constituents and antibacterial activities of the aqueous leaf extracts of Vernonia amygdalina (ALEVA) and Ocimum gratissimum (ALEOG). In ALEVA using the agar-well diffusion method. The ALEVA contained 35 identified compounds, with cis-thujopsene (20.99%), acetic acid (20.77%), and butanoic acid, 2-methyl (12.87%) being the most abundant. Ethosuximide and cyclohexane, 1, 3-butadienylidene were detected in small amounts. The ALEOG had 44 compounds, with butanoic acid, 3-methyl (13.89%), thymol (12.43%), and butanoic acid, 2-methyl (7.22%) in the highest concentrations, while 1H-cyclopenta[a] pentalen-7-ol and 9-octadecynoic acid methyl ester were present in small amounts. The ALEOG and ALEVA showed significant (p < 0.05) inhibition at 40 mg/mL against Helicobacter pylori and other bacterial isolates, with a highest mean (x S.D.) inhibition zone diameter of 17.5 0.5 mm and 18.2 1.1 mm, respectively. The minimum inhibitory concentrations (MIC) values of ALEVA and ALEOG for the isolates ranged between 5 g/mL and 40 g/mL; the minimum bactericidal concentrations (MBC) values of ALEVA and ALEOG for the isolates ranged between 5 g/mL and 80 g/mL, with an MBC/MIC of 4. The study has demonstrated that aqueous leaf extracts from O. gratissimum and V. amygdalina possess significant antibacterial activity, supporting their traditional medicinal uses.

In-vitro Antimicrobial Activity of ZnO Nanoparticles Produced by Hydrothermal Method Against Some Foodborne Pathogens

Zinc oxide nanoparticles (ZnO-NPs) are synthesized via a multitude of techniques, resulting in nanoparticles of varying sizes and morphologies that directly influence their antimicrobial efficacy. The objective of this study is to ascertain the particle size and morphology of ZnO-NPs synthesised via the hydrothermal method and to evaluate their in vitro antibacterial effects against Escherichia coli O157, Salmonella Typhimurium, and Listeria monocytogenes, which are important foodborne pathogens. The ZnO-NPs were examined using a scanning electron microscope (SEM). Furthermore, the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and the diameter of inhibition zones were measured against these pathogenic bacteria. The SEM images revealed that the ZnO-NPs exhibited a uniform distribution, with particle sizes ranging between 23 and 25 nm. The MIC and MBC values against the tested strains were found to range from 20.83 to 41.67 µg/mL and between 66.67- 83.33 µg/mL, respectively. In addition, the diameter of inhibition zones were ranged from 15.16 to 16.96 mm. The findings of the study demonstrated that ZnO-NPs s synthesized via the hydrothermal method exhibited antibacterial effects against both Gram-positive and Gram-negative bacteria. In conclusion, the use of ZnO-NPs can facilitate the improvement of the microbiological quality of foods by the inhibition of foodborne patogens.

In Vitro Evaluation of Rosemary Essential Oil: GC-MS Profiling, Antibacterial Synergy, and Biofilm Inhibition.

Background: Antimicrobial resistance (AMR) has become precarious, warranting investments in antimicrobial discovery. Aim: To investigate the antibacterial activity of rosemary essential oil (REO), alone and in combination with selected conventional antibiotics. Methods: REO was subjected to antimicrobial susceptibility testing (including minimum bactericidal concentration (MBC) and minimum inhibitory concentration (MIC) determination) and investigation of anti-pre-biofilm and antibiofilm activities. Results: The phytochemical composition of the REO was eucalyptol (42.68%), bornanone (33.20%), endo-borneol (9.37%), α-terpeneol (7.95%), linalool (2.10%), bornyl acetate (1.81%), caryophyllene (1.09%), 4-terpeneol (0.94%), and anethole (0.87%). The antibacterial inhibition zones generally increased with increasing REO concentration (i.e., 10, 20, 50, 100, and 200 mg/mL). The MIC and MBC ranges of REO for all bacteria were 3.13-6.25 mg/mL and 3.12-12.5 mg/mL, respectively. The MICs (in µg/mL) of ciprofloxacin, chloramphenicol, streptomycin, tetracycline, and ampicillin, respectively, were Escherichia coli (0.98, 3.92, 1.96, 7.81, and 250), Klebsiella pneumoniae (1.25, 7.81, 125, 7.81, and 1000), MRSA (62.5, 7.81, 3.91, 7.81, and 250), Streptococcus mutans and Bacillus subtilis (125, 15.68, 250, 31.25, and 1000), Pseudomonas aeruginosa (125, 31.25, 500, 31.25, and 1000), and Salmonella Typhi (0.98, 15.68, 125, 1.96, and 1000). The MBC-MIC ratios of REO against all bacteria were in the range 1-2, indicating bactericidal effects. Mainly synergy (FICI = 0.16-0.37) was observed between REO and the conventional antibiotics. The IC50 values (in µg/mL) of REO against the bacteria, pre-biofilm vs. biofilm formation, were E. coli (1342.00 vs. 4.00), K. pneumoniae (106.00 vs. 3.00), MRSA (134.00 vs. 6.00), S. mutans (7259.00 vs. 7.00), B. subtilis (120.00 vs. 7.00), P. aeruginosa (4989.00 vs. 7.00), and S. Typhi (10.00 vs. 2.00). Conclusions: Rosemary essential oil had significant bactericidal effects on the bacteria tested, and its MIC and MBC values were low. Overall, it was synergistic with known conventional antibiotics and, thus, has encouraging prospects in combination therapy involving conventional antibiotics, even in the treatment of infections with multidrug-resistant bacteria, including biofilm-forming ones.

Comparative Evaluation of Antimicrobial Effect of Different Irrigating Solution Against Enterococcus Faecalis - An In-Vitro Study

BACKGROUND The invasion of microorganisms into the root canal system poses a significant challenge in endodontic infections, especially in primary teeth. Enterococcus faecalis is a common culprit in such infections, necessitating effective antimicrobial strategies. This study aims to assess various irrigating solutions' antimicrobial efficacy against E. faecalis. Aim: The aim of this study was to evaluate the antimicrobial efficacy of different irrigating solutions against E. faecalis. METHODS Six experimental groups, including lemon extract, chlorine dioxide solution, apple cider vinegar, Echinacea angustifolia, sodium hypochlorite, and a control group (normal saline), were evaluated. The antimicrobial activity was assessed using the agar-well diffusion method, and MIC (Minimum Inhibitory Concentration) and MBC (Minimum Bactericidal Concentration) were determined. RESULTS Lemon extract and apple cider vinegar exhibited higher zones of inhibition compared to sodium hypochlorite, chlorine dioxide, and Echinacea angustifolia. Statistical analysis confirmed significant differences in antimicrobial efficacy between various groups. Lemon extract and apple cider vinegar demonstrated the lowest MIC and MBC values, indicating potent antimicrobial activity against E. faecalis. CONCLUSIONS This study highlights the antimicrobial efficacy of lemon extract and apple cider vinegar against E. faecalis, suggesting their potential as alternative irrigating solutions in endodontic practice. Further research is warranted to explore their clinical applicability and long-term effects on treatment outcomes.

Effects of Petasitin as Natural Extract on Proliferation and Pathological Changes of Pediatric Neuroblastoma SK-N-SH Cells

Scalp alopecia areata (SAA) is a common non-scarring hair loss condition, associated with factors such as autoimmune responses, genetics, emotional stress, and endocrine imbalances. Current treatments for SAA included minoxidil, topical steroid creams, biologics, and plant extracts. Tea tree oil (TTO), a natural plant extract, is known for its antibacterial, anti-inflammatory, and acaricidal properties, and it also provides nourishment for hair. In this research, a natural extract of TTO, was prepared to analyze its antibacterial properties. The hair follicle stem cells (HFSCs) of patients with primary SAA were analyzed to understand the influences of TTO on migration of HFSCs. TTO was extracted from fresh tea tree leaves using steam distillation. Quantitative analysis of gas chromatography-mass spectrometry (GC/MS) qualitative analysis and its total ion chromatogram using area normalization method were conducted. Meanwhile, its antibacterial activity was tested against five common pathogens (Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), Staphylococcus albus (S. albus), Pseudomonas aeruginosa (P. aeruginosa), and Candida albicans (C. albicans)) by measuring the diameter of inhibition zones (DIZ), minimal inhibitory concentration (MIC), and minimum bactericidal concentration (MBC). HFSCs were isolated from patients with SAA and cultured in vitro, with cell identification performed through cytokeratin 15 (K15) immunofluorescent staining. The HFSCs were then exposed to varying concentrations (0.0, 0.5, 2.0, 5.0, 10.0, and 25.0 mmol/L) of TTO for culture, and cell proliferation activity (CPA) was assessed using the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) assay, while migration of HFSCs was evaluated using the Transwell chamber assay. Results demonstrated that the extracted TTO had a content of 0.69 g and an extraction rate of 2.32%. 36 components were identified, constituting 98.67% of the total, with 4-terpineol reaching a high concentration of 48.35%. It exhibited a DIZ of less than 25 mm against all tested pathogens, with MIC values lower than 29 mg/mL and MBC values below 38 mg/mL. Patients with SAA displayed yellow and black dots, broken hair, malnourished and exclamation mark hairs, with few flag hairs observed in skin microscope examination. Isolated and cultured HFSCs expressed K15 primarily in the cytoplasm and exhibited favorable growth dynamics. Treatment with various concentrations of TTO greatly increased CPA and migrated cell numbers in HFSCs, with the optimal effect observed at 5.0 mmol/L concentration of TTO. In conclusion, the plant extract TTO possessed significant antibacterial activity and can promote proliferation and migration in vitro of HFSCs, suggesting its potential therapeutic application for SAA.

Chemical composition and antimicrobial activity of Marrubium deserti de Noé essential oil

The main objectives of this study were to determine the chemical composition of the essential oil of Marrubium deserti de Noé (EOMD) from Bechar (Algeria), and to evaluate its physicochemical properties, antibacterial and antifungal activities. The yield of EOMD was 0.29±0.008%, with the main components being α-phellandrene (25.05%), β-pinene (14.05%), and α-pinene (12.83%). Both gram-negative and gram-positive bacteria were significantly inhibited by EOMD with inhibition zones ranging from 7.00±0.00 mm to 22±1.33 mm, and with minimum inhibitory concentrations (MICs) and minimum bactericidal concentration values ranging from 0.0022 to 0.014 v/v; likewise, intriguing antifungal activity against pathogen fungi was noticed with MICs and minimum fungicidal concentration values ranging from 0.00125 to 0.006 v/v. Furthermore, the studied essential oil demonstrated a total suppression of the sporulation and germination of spores at concentrations as from 0.002 v/v. These results emphasize the bactericidal and fungicidal characteristics of EOMD and their prospective usage as a substitute for synthetic bactericides and fungicides

AKTIVITAS ANTIBAKTERI DAN ANTIBIOFILM DARI EKSTRAK DAUN BANGUN-BANGUN (Coleus amboinicus L.) TERHADAP BAKTERI Staphylococcus aureus

Biofilm formation by bacteria, especially the genus Staphylococcus, is a serious health problem. Various medicinal plants have been used to control the infection, but research related to the antibiofilm activity of Coleus amboinicus is still limited. Bangun-bangun leaves (C. amboinicus) are plants from the Lamiaceae family that contain secondary metabolites such as terpenoids, flavonoids, and phenolics that are thought to be responsible as antibacterial and antibiofilm. This study aims to examine the antibacterial and antibiofilm activity of C. amboinicus against S. aureus. C. amboinicus leaves were extracted using 96% ethanol. The ethanol extract was then screened for phytochemicals using Thin Layer Chromatography (TLC) using several spray reagents. Antibacterial activity was analyzed using microdilution technique to obtain the value of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Antibiofilm activity was analyzed using crystal violet method. The result showed that the ethanol extract of C. amboinicus leaves contained flavonoids, phenolic terpenoids, and tannins. Antibacterial assays were obtained for the MIC value of 8 mg/mL and MBC of 16 mg/mL. The ethanol extract showed biofilm inhibitory activity with an IC50 value of 2,40 mg/mL. Based on these results, C. amboinicus has potential antibacterial and antibiofilm activity to inhibit S. aureus.

Novel natural and economic approach for controlling methicillin-resistant Staphylococcus aureus using apple cider vinegar

Methicillin-resistant Staphylococcus aureus (MRSA) constitutes a significant health concern because it promotes infectious mastitis in dairy animals and poses a hazard risk to humans. Controlling MRSA infections is a growing challenge on a global scale because of the bacteria's toxicity and its capacity to develop multidrug resistance (MDR). Combating against MDR bacteria and the spread of infectious diseases needs natural antibacterial alternatives to minimize the economic losses of mastitis. The average treatment cost in Egypt was highlighted. The antibacterial effect of apple cider vinegar (ACV) against MDR-MRSA isolates was evaluated, also the study aimed at profiling antimicrobial resistance genes in MRSA isolates. The incidence of mastitis in cows was more than in buffaloes, and the average total treatment cost was estimated at 82 million EGP from 2016 to 2021 (around 14 million EGP annually). Of the 22 S. aureus isolates (20 %), of which (59.1 % were from cows and 40.9 % from buffaloes), 19 (86.4 %) were confirmed as MRSA. All MRSA isolates exhibited resistance to clindamycin (94.7 %), then both ampicillin and doxycycline (84.2 %), and ampicillin and sulbactam, erythromycin and Fosfomycin (each, 78.9 %). Vancomycin, ciprofloxacin, and levofloxacin can be used to treat MRSA. The prevalence of MDR was significantly high, with 94.7 % of the cases having multiple antimicrobial resistance (MAR) indices ranging from 0.25 to 0.75. All MRSA isolates tested positive for mecA, 89.5 % for the blaZ gene, 84.2 % for tetM, and 73.4 % for ermB. In vitro, the antibacterial properties of ACV were demonstrated to be superior by our results which demonstrate a zone of inhibition with diameters ranging from 20 to 40 mm detected by Agar well diffusion technique and MIC's (Minimal Inhibitory Concentration) ranging from 2 to 4 μg/ml. Some isolates possess MBC (Minimal Bactericidal Concentration) values at the same MIC. This research proposes the potential of ACV to act as a promising antibacterial alternative against MRSA. This can help minimize the health problem of antibiotic-resistant bacteria and improve the efficiency of dairy farms. Further studies are recommended to determine the proper dosage for field administration.

Antibacterial Activity of Ethanolic Extract of Cardiospermum halicacabum against Methicillin-Resistant Staphylococcus aureus

We investigated the antibacterial activity of Cardiospermum halicacabum extract against methicillin-resistant Staphylococcus aureus (MRSA) via the disk diffusion method and identified the plant’s bioactive phytochemicals. Additionally, we evaluated the synergistic effects, and primary mechanism of action of the plant extract against the S. aureus strain PB57 (MRSA). The ethanolic extract of C. halicacabum contained beneficial secondary metabolites such as the flavonoids apigenin, terpenoids and tannins. The total phenolic content, expressed as the gallic acid equivalent (g GAE/kg), was 87.66 ± 14.56 g GAE/kg at a concentration of the 1 mg/mL. The plant extract inhibited and killed the S. aureus strain PB57 with minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values of 0.98 mg/mL. Electron microscopy revealed that the plant extract caused damage to the ultrastructures of the cells of the pathogens. The compounds in the extract remained below known maximum acceptable cytotoxicity thresholds for fibroblast cells, which are typically in the range of [include specific value from relevant guidelines or literature]. Further cytotoxicity assays are required to determine the precise safety margins for therapeutic use. Although the extract showed promise against MRSA, its application as a broad treatment for infectious diseases requires more specific testing on other pathogens. Based on the scope of our research, C. halicacabum could be a viable candidate for the development of treatments targeting MRSA-related infections. HIGHLIGHTS Our investigation revealed that the ethanolic extract of Cardiospermum halicacabum exhibited significant antibacterial activity against the methicillin-resistant Staphylococcus aureus (MRSA) strain PB57. The extract contained beneficial secondary metabolites, including flavonoids such as apigenin, as well as terpenoids and tannins. Moreover, the electron microscope shown that the extract disrupted the pathogen’s cell structures and, despite showing some cytotoxicity at higher doses, remained within safe limits, positioning C. halicacabum as a potential treatment for infectious diseases. GRAPHICAL ABSTRACT

Physicochemical properties, GC–MS profiling, and antibacterial potential of Allium sativum essential oil: In vitro and in silico approaches

Antibiotic resistance remains a critical challenge for public health. In this study, we investigate the antibacterial potential of Moroccan Allium sativum L. essential oil (EO) through both in vitro and in silico approaches. The EO was extracted using hydrodistillation, and its physicochemical properties were analyzed alongside its chemical composition via gas chromatography-mass spectrometry (GC/MS). We assessed antibacterial efficacy through disk diffusion assays targeting Escherichia coli (E. coli), methicillin-resistant Staphylococcus aureus (MRSA), and Pseudomonas aeruginosa (P. aeruginosa), and determined the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. Finally, an in silico molecular docking analysis and ADMET (absorption, distribution, metabolism, excretion, and toxicity) prediction were performed. Our analysis identified 13 sulfur-based compounds within the EO, with diallyl disulfide (42.85 %), methylallyl disulfide (18.84 %), methylallyl trisulfide (15.38 %), and diallyl trisulfide (13.11 %) as major constituents. The EO demonstrated robust activity against MRSA, with an inhibition zone of 22 mm and an MIC of 0.75 mg/mL, whereas E. coli exhibited lower sensitivity, with an MIC of 1.51 mg/mL. Molecular docking analysis suggested that the primary sulfur compounds may effectively inhibit bacterial resistance-related enzymes. These findings highlight the potential of Allium sativum L. EO as a natural antibacterial agent, attributed largely to its sulfur compound content. This activity is likely linked with the EO's interaction with the complex structures of bacterial cell membranes, offering promise in combating resistant bacterial strains.

Exploring the Antibacterial Properties and Chemical Profiles of Essential Oils from Syzygium aromaticum and Nigella sativa Against MDR Bacteria

For centuries, plants have been studied for their healing properties. Recently, the rise of antibiotic resistance in bacteria has prompted scientists to explore herbal remedies. Syzygium aromaticum, from the Myrtaceae family, has been utilized as a histological clearing agent. In contrast, Nigella sativa (black cumin), a member of the Ranunculaceae family, has long been utilized in traditional medicine dating back to ancient times. The current study investigates the chemical composition and antibacterial activity of essential oils from Syzygium aromaticum (clove) and Nigella sativa (black cumin) against multidrug-resistant (MDR) bacteria. Using the agar well diffusion method, Syzygium aromaticum exhibited significant antibacterial activity, particularly against Salmonella typhi (30.66 mm inhibition zone), while Nigella sativa was effective only against Staphylococcus aureus (19 mm). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values for Syzygium aromaticum ranged from 3.53 to 7.06 mg/mL, indicating stronger antibacterial properties than Nigella sativa (MIC: 12.7 mg/mL, MBC: 22.5 mg/mL). GC-MS analysis revealed that Syzygium aromaticum contained bioactive compounds like Diglycolic acid (76.59%) and Eugenol (2.06%), while Nigella sativa was dominated by Heptasiloxane (80.83%) and Thymoquinone (2.66%). These findings suggest that Syzygium aromaticum essential oil could serve as a potent natural antimicrobial agent against MDR pathogens.

ANTIOXIDANT, INHIBITION OF ADVANCED GLYCATION END-PRODUCT FORMATION AND ANTIMICROBIAL ACTIVITIES OF OCIMUM GRATISSIMUM (SCENT LEAF) METHANOLIC LEAF EXTRACT AGAINST Escherichia coli AND Bacillus SPP

The study investigates the antioxidant, inhibition of advanced glycation end-product formation and antimicrobial activities of methanolic leaf extract of Ocimum gratissimum. GC-MS, qualitative, antioxidant scavenging and antiglycation activities of the extract of Ocimum gratissimum were determined using standard procedures. The antimicrobial activity was evaluated by agar well diffusion method. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined using standard methods. The GC-MS analysis of Ocimum gratissimum leaf revealed the presence of 49 compounds with P –cymene been the most abundant. The phytochemical screening of the extract shows the presence of alkaloids, tannins, phenolic, flavonoids, saponins etc. The in-vitro antioxidant assay of the extract was found to have ?-carotene, lycopene, total phenolic compounds, total flavonoid compounds, reducing power and DPPH scavenging activities. The extract showed significant inhibitory effects on the formation of compounds containing two carbonyl groups and Advanced Glycated End products formation with IC50 of 75.85 ±4.87 µg/mL. Agar well diffusion assay was characterized by inhibition zones of 21.0 ± 0.30, 19.66 ± 0.20, 33.78± 0.30 and 33.25 ± 0.40 mm for Escherichia coli and Bacillus spp respectively at 250 mg/ml for Ocimum gratissimum and 25 mg/ml for tetracycline solution. The MIC values for E.coli and Bacillus spp were 33.33, 66.67, 0.78 and 0.78 for both extract and tetracycline while their MBC values were 66.67, 133.00, 1.56 and 1.56 respectively. MBC/ MIC values showed that Ocimum gratissimum extract and tetracycline had bactericidal effects. These results indicated that Ocimum gratissimum possesses antioxidant, prevents glycation and has antimicrobial activities.