Minimum Bactericidal Concentration Values Research Articles

Antibacterial activity and mechanism of chelerythrine against Streptococcus agalactiae.

Streptococcus agalactiae (S.agalactiae), also known as group B Streptococcus (GBS), is a highly infectious pathogen. Prolonged antibiotic usage leads to significant issues of antibiotic residue and resistance. Chelerythrine (CHE) is a naturally occurring benzophenidine alkaloid and chelerythrine chloride (CHEC) is its hydrochloride form with diverse biological and pharmacological activities. However, the antibacterial mechanism of CHEC against GBS remains unclear. Thus, this study aims to investigate the in vitro antibacterial activity of CHEC on GBS and elucidate its underlying mechanism. The antibacterial effect of CHEC on GBS was assessed using inhibitory zone, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) assays, as well as by constructing a time-kill curve. The antibacterial mechanism of CHEC was investigated through techniques such as scanning electron microscopy (SEM) and transmission electron microscopy (TEM), measurement of alkaline phosphatase (AKP) activity, determination of Na+ K+, Ca2+ Mg2+-adenosine triphosphate (ATP) activity, observation of membrane permeability, and analysis of intracellular reactive oxygen species (ROS) and mRNA expression levels of key virulence genes. The results demonstrated that the inhibition zone diameters of CHEC against GBS were 14.32 mm, 12.67 mm, and 10.76 mm at concentrations of 2 mg/mL, 1 mg/mL, and 0.5 mg/mL, respectively. The MIC and MBC values were determined as 256 μg/mL and 512 μg/mL correspondingly. In the time-kill curve, 8 × MIC, 4 × MIC and 2 × MIC CHEC could completely kill GBS within 24 h. SEM and TEM analyses revealed significant morphological alterations in GBS cells treated with CHEC including shrinkage, collapse, and leakage of cellular fluids. Furthermore, the antibacterial mechanism underlying CHEC's efficacy against GBS was attributed to its disruption of cell wall integrity as well as membrane permeability resulting in extracellular release of intracellular ATP, AKP, Na+ K+, Ca2+ Mg2+. Additionally CHEC could increase the ROS production leading to oxidative damage and downregulating mRNA expression levels of key virulence genes in GBS cells. In conclusion, CHEC holds potential as an antimicrobial agent against GBS and further investigations are necessary to elucidate additional molecular mechanisms.

Efeito antibacteriano de extratos brutos aquosos e etanólicos de Asphodelus fistulosus sobre bactérias gram-positivas e gram-negativas

Asphodelus fistulosus (A. fistulosus) is a wild plant grows in Jordan. Traditionally, it is used to treat different medical conditions and diseases such as respiratory ailments, against burns and dermatomucosal infections.This study aims to find out the effects of A. fistulosus aqueous and ethanolic crude extracts on Staphylococcus aureus(S. aureus) as gram positive bacteria and Escherichia coli (E. coli) as gram negative bacteria and to investigate which one will be affected either by aqueous and/or ethanolic crude extracts of A. fistulosus shooting parts that were collected from Jerash in the north of Jordan. Agar well diffusion method was used to evaluate the antibacterial activity of the crude extracts. In addition, MIC (minimum inhibitory concentration) as well as MBC (minimum bactericidal concentration) were determined against both types of bacteria. The results showed that flower aqueous extract of A. fistulosus was very effective against E. coli (20.0 ± 0.50) mm and caused a (14.0 ± 0.50) mm inhibition to S. aureus. The ethanolic extract of stem was very effective cauesed a (19.0 ± 0.50) mm inhibition in both bacterial species. Respectively, both S. aureus and E. coli were inhibited by ethanolic and aqueous extracts (mixture1 and mixture2) (15.0 ± 0.00 mm and 10.5 ± 0.50 mm). The highest antimbacterial activity was observed for the leaves aqueous extract against E.coli (0.06120 mg/mL). The obtained MIC values from A. fistulosus parts extracts demonstrated antibacterial activity ranged between 7.606 and 0.06120 mg/mL. The highest antimicrobial activity was recorded in the leaves aqueous extract against E. coli.The MBC value of stem aqueous extract was 5.00 mg/mL against both S. aureus and E. coli. On the other hand, ethanolic and aqueous extracts of the leaves gave MBC values 5.00 mg/mL, and 0.156 mg/mL, respectively, against E. coli.Based on the results of this study, it can be concluded that there is good inhibitory effect of aqueous and ethanolic of A. fistulosus shooting parts extracts on growth of E. coli and S. aureus. Adding to that, stem ethanolic extract has the most effective against S. aureus while aqueous extract of flower has the most effective against E. coli.So, it is recommended to have further future studies on the A. fistulosus shooting parts crude extract bioactive components and the mechanism of how these constituents affect these types of bacteria.

Psidium guajava extract-mediated iron, vanadium, and silver ternary oxide nanoparticles for sustainable antibacterial applications

This study investigated the antimicrobial potential and structural characteristics of Fe-Ag-V nanoparticles synthesized from Psidium guajava leaves extract. The nanoparticles demonstrate significant antimicrobial efficacy against bacterial strains, including Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Bacillus cereus, with low Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values. Synthesized eco-consciously, they offer promise in combating infections while supporting sustainability goals. Structural analysis via X-ray diffraction (XRD) and Dynamic Light Scattering (DLS) confirms their face-centered cubic (FCC) crystal structure and rod-like morphology with internal pores, suggesting diverse applications. DLS revealed an average particle diameter of approximately 94.59 nm, enhancing reactivity in catalysis and drug delivery. This study emphasizes the antimicrobial efficacy and structural attributes of Psidium guajava Extract-Derived Fe-Ag-V nanoparticles, suggesting their potential across scientific disciplines, from medicine to materials science, for combating infectious diseases sustainably.

Disentangling the "tip-effects" enhanced antibacterial mechanism of Ag nanoparticles.

Silver nanoparticles (Ag NPs) exhibit strong antibacterial activity and are widely used in industries such as medical, food and cosmetics. In this study, Ag nanospheres and Ag nanotriangles are selected as antibacterial agents to reveal the distinct mechanism of tip effects towards their antibacterial performance. A series of antibacterial experiments were implemented, including in situ monitoring as well as studying and determining the evolution of the inhibition zone, minimum inhibitory concentration (MIC)/minimum bactericidal concentration (MBC) values, growth kinetics, bactericidal curve, bacterial morphologies and intracellular reactive oxygen species (ROS). Ag nanotriangles can eradicate E. coli and S. aureus at extremely low concentrations in comparison to Ag nanospheres, in particular under sunlight irradiation. The destroyed bacterial cell walls were examined by scanning electron microscopy. Through the investigation of ROS production, the generation efficiency of ROS is improved by the merit of sunlight irradiation thanks to the localized surface plasmon resonance (LSPR) properties of Ag NPs. However, a more significant improvement in ROS generation efficiency occurred in the presence of Ag nanotriangles contributed by the pronounced "tip effects". This study sheds light on the structure-performance relationship for the rational design of antibacterial agents.

Antimicrobial activity of hydralazine against methicillin-resistant and methicillin-susceptible Staphylococcus aureus.

Background: Staphylococcus aureus is a human pathogen responsible for high mortality rates. The development of new antimicrobials is urgent. Materials & methods: The authors evaluated the activity of hydralazine along with its synergism with other drugs and action on biofilms. With regard to action mechanisms, the authors evaluated cell viability, DNA damage and molecular docking. Results: MIC and minimum bactericidal concentration values ranged from 128 to 2048μg/ml. There was synergism with oxacillin (50%) and vancomycin (25%). Hydralazine reduced the viability of biofilms by 50%. After exposure to hydralazine 2× MIC, 58.78% of the cells were unviable, 62.07% were TUNEL positive and 27.03% presented damage in the comet assay (p<0.05). Hydralazine showed affinity for DNA gyrase and TyrRS. Conclusion: Hydralazine is a potential antibacterial.

Evaluation of the antimicrobial activity of Eucalyptus radiata essential oil against Escherichia coli strains isolated from meat products.

The present study sought to evaluate the antimicrobial and anti-adherent potential of Eucalyptus radiata essential oil against food-borne strains of Escherichia coli. The study was performed using the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). In addition, the disk diffusion technique was used to evaluate the association of Eucalyptus radiata essential oil with synthetic antimicrobials. The Minimum Inhibitory Adherence Concentration (MIC) was also performed. The results revealed that E. radiata showed antimicrobial activity against the E. coli strains tested, with MIC values ranging from 500 μg/mL to 1000 μg/mL and MBC values ranging from 500 μg/mL to 1,024 μg/mL. As for the associations, it was observed that E. radiata oil exhibited a synergistic effect for some antibiotics, especially Ceftriaxone, with greater interference from the essential oil. Furthermore, it was effective in inhibiting the adherence of bacterial strains of E. coli, showing a more significant antibiofilm effect than the antibacterial agent 0.12% chlorhexidine digluconate. In summary, the essential oil of E. radiata showed antimicrobial potential against strains of E. coli of food origin, and can therefore, through in-depth studies, be used alone or in association with synthetic antimicrobials to combat infections caused by this pathogen.

Antibacterial Activity of Terminalia mantaly Stem Ethanol Extract as Hand Sanitizer Gel

Background: Hand sanitizers generally contain alcohol. However, it can cause dry and irritated skin. Therefore, it is necessary to find antibacterial alternatives that are safe for the skin. One of the plants that has antibacterial activity is Terminalia mantaly (T. mantaly). This study aimed to investigate the antibacterial activity of ethanol extract and hand sanitizer gel of T. mantaly.Methods: The antibacterial activity test against gram-positive (Staphylococcus aureus and Streptococcus pyogenes) and gram-negative bacteria (Escherichia coli and Shigella dysenteriae) was carried out using the liquid micro dilution method. The phytochemical tests were also performed. This study was conducted at the Chemistry Laboratory, Faculty of Sains and Informatics, Universitas Jenderal Achmad Yani in April-June 2022.Results: The ethanol extract of T. mantaly stem contained secondary metabolites of alkaloids, tannins, quinones, saponins, steroids, and flavonoids. The minimum inhibitory concentration (MIC) values of T. mantaly stem ethanol extract against Escherichia coli, Shigella dysenteriae, Staphylococcus aureus, Streptococcus pyogenes were 0.63%, 0.63%, 0.16%, and 0.16%, whereas the hand sanitizer gel gave MIC values of 0.63%; 0.31%; 0.16%; and 0.16% respectively. The minimum bactericidal concentration (MBC) values of T. mantaly stem ethanol extract and hand sanitizer gel had the same results, namely 2.50%, 0.16%, 1.25%, and 1.25%. The physical stability of the hand sanitizer gel from the ethanol extract of T. mantaly stem met the physical stability standards of the gel. Conclusions: The ethanol extract of the T. mantaly stems has stronger antibacterial activity against gram-positive bacteria than against gram- negative bacteria.

Antibacterial Efficacy of Essential Oils from Four Spices against Salmonella typhimurium: Mathematical Modelling and Application in Enhancing Salad Cream Safety

The study was conducted to investigate the inhibitory effects of certain natural substances (finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom) against Salmonella typhimurium, a type of bacteria known to cause foodborne illnesses. The result showed that finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom exhibited strong inhibitory effects against S. typhimurium. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were evaluated. MIC values ranged from 0.049 to 0.781 µl/ml, and MBC values ranged from 0.049 to 6.250 µl/ml. Furthermore, the study aimed to develop mathematical models that accurately describe S. typhimurium survival in the presence of these essential oils. By understanding how the S. typhimurium respond to the oils over time, it was found that the mathematical models accurately described bacterial survival, with the modified Gompertz model fitting for finger root essential oil and the Weibull and modified Gompertz models suitable for the other oils. Additionally, the study sought to evaluate the practical viability of incorporating these essential oils into salad cream formulations, primarily aiming to assess their potential in reducing S. typhimurium counts and ensuring compliance with established quality standards. Specifically, the inclusion of finger root, clove, lemongrass, cardamom, and the combination of lemongrass with cardamom in salad cream formulations, maintained at a controlled temperature of 4 °C, yielded positive outcomes, meeting the required quality standards. Importantly, the presence of S. typhimurium was rendered undetectable, and an overall reduction in microbial count was observed when compared to cream formulations lacking these essential oils. This study effectively underscores the potential of the examined essential oils as natural antimicrobial agents suitable for incorporation in food products

POTENTIAL OF CITRUS LEAF EXTRACT (Cymbopogon citratus (DC.) Stapf) AS AN ANTIBACTERIAL INHIBITORY of Staphylococcus epidermidis

The concerns of antibiotic resistance have increased in recently years, this issue caused by long-term repeated use of antibiotics to treat bacterial illnesses. Lemongrass leaf (Cymbopogon citratus (DC.) Stapf) is one of the natural ingredients that can be used as an alternative antibacterial. The study objective is to determine the antibacterial activity of the ethanol extract of 70% cooking leaves against Staphylococcus epidermidis using diffusion methods. In addition, the Minimum inhibitory concentration (MIC) and Minimum bactericidal concentration (MBC) of extracts were determined using liquid dilution methods. The results of this study show that extract concentrations of 1,000,000 ppm have a barrier zone in the intermediate category when compared with the positive control, that is, clindamycin. Meanwhile, the MIC value obtained is 1250 ppm, while the MBC value is 5000 ppm. The results of statistical analysis showed that there were no significant differences in the inhibition zone diameter formed between the test concentrations.

Isolation and Characterization of Staphylococcus aureus from Raw Cow's Milk and Investigating the Effect of Bifidobacterium bifidum Probiotic Cell Free Supernatant on Their Enterotoxins Genes Expression.

The present reserach aimed to detect and isolate the genes involved in the staphylococcal enterotoxins (SEs) production in strains isolated from unprocessed cow's milk and to examine the impact of Bifidobacterium bifidum probiotic cell-free supernatant (CFS) on their expression. Standard techniques were used for isolation and identification of Staphylococci strains in unprocessed milk. The PCR was used to identify strains carrying enterotoxin genes. The B. bifidum CFS was applied to strains containing the target genes, and the genes expression levels were quantified using Real-time PCR. Using 16SrDNA sequencing, the phylogenic relationship of the isolated strains was determined. Analysis revealed that bacteria such as Staphylococcus species were found in the 72% of the samples. The PCR test showed the presence of various SE superantigens, including SEA (16.7%), SEC (11.7%), SED (8.3%), SEE (6.7%), and SEB (1.7%) in isolated strains. The B. bifidum CFS had obvious antimicrobial activity against strains 24, 51, 54, and 35 of Staphylococcus species, and the minimum inhibitory concentration and minimum bactericidal concentration values for these strains treated with B. bifidum CFS were in the range of 31.25-125 μg/ml. Strains 51 and 24 were clustered with S.aureus ATCC 25923, and strains 54 and 35 were clustered with S.aureus ATCC 12600, respectively. The RT-PCR exhibited that probiotics CFS suppressed the expression of SEA, SEB, SEC, and SEE genes (P<0.05). The average fold change for SEA, SEB, SEC, and SED genes was -1.681, -1.28, -1.52, and -0.84, respectively. The research demonstrated that probiotic bacteria can lower enterotoxin production by downregulating the expression of SEs genes.

Enhancing biological activities and phenolic content of wild grapevine roots by severe drought stress

Wild grapevines are a rich source of polyphenolic compounds. Various environmental factors can influence these bioactive metabolites, contributing to stress mitigation and adaptation. The present study aimed to investigate the impact of prolonged drought stress on the accumulation of phytochemicals, antioxidants, and antimicrobial activity in the roots of the endangered Tunisian wild grapevine (Vitis vinifera subsp. sylvestris) "Tebaba" genotype. The results revealed that under prolonged drought stress, there was a significant increase in total phenolic compounds, total flavonoid content, and stilbenes, which showed a positive and significant correlation with the total antioxidant activity. Furthermore, the ethanolic extracts demonstrated an enhanced in vitro antibacterial effect against selected human pathogenic bacterial strains, including Staphylococcus aureus, Methicillin-resistant S. aureus, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values, relative to prolonged drought stress, ranged from 125 to 250 µg/mL. The values of the ratio between MBC and the MIC showed that the activity of the root extract was bactericidal in all cases (MBC/MIC ≤ 2). This study highlights the potential of wild grapevine roots enriched with drought-inducible phenolic compounds, as a promising source of antimicrobial agents relevant to human health applications.

Antimicrobial activity of essential oils (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogen strains isolated in milk samples from mastitic sheep

The aim of this investigation was to study in vitro antibacterial activity of essential oils (EOs) (Citrus bergamia Risso & Poiteau, Melaleuca alternifolia and Chenopodium botrys) on pathogenic strains isolated in milk samples from mastitic sheep. The in vitro antibacterial activity showed that EOs induced higher bacterial inhibition against pathogens isolated in mastitic milk (Staphylococcus xylosus, Staphylococcus epidermidis, Streptococcus salivarius, Enterococcus faecium, Streptococcus agalactiae and Pseudomonas aeruginosa) than common antimicrobial agents used in veterinary medicine, with Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values significantly lower, excepted for P. Aeruginosa. The antibacterial activity of EOs has been attributed to the chemical composition of each phyto-complexes, constituted by monoterpenes, sesquiterpenes and their associated alcohols, identified by GC-MS analysis, with a synergic action in the bacterial cells. The results obtained confirmed in vitro antimicrobial activity of these EOs and their potential use in the treatment of sheep mastitis infection.

Biological Activity of Red Pitahaya Extracts on Lactococcus garvieae and Vibrio alginolyticus

The enhancement population of the world every day brings with it the demand for protein needs. In our study, it was aimed to identify the utilization potential of red pitahaya fruit obtained from Turkey as a natural feed additive. The disc diffusion assay, micro-dilution method for determination of minimum inhibitory (MIC) and minimum bactericidal (MBC) concentration values of the extracts were used to identify the biological activity of the extracts from red pitahaya. The red pitahaya pulp methanol extract against L. garvieae and V. alginolyticus showed 10.61 mm and 7.65 mm of inhibition zone diameters. The methanol extract of red pitahaya peel has 10.18 mm and 11.25 mm inhibition zone diameters on L. garvieae and V. alginolyticus. MIC values were determined as 20 µg/µl and 40 µg/µl for pulp methanol extract and as 80 µg/µl and 40 µg/µl for peel methanol extract against L. garvieae and V. alginolyticus. MBC values of pulp and peel methanol extracts against fish pathogens were determined as 80 µg/µl. As a result, the red pitahaya extracts may have usage potential as natural antimicrobial agents or feed additive in aquaculture.

Antibacteria Activity Peel and Seed Extracts of Rambutan (Nephelium lappaceum L.) Against MDR Bacteria Causing Urinary Tract Infections

Multidrug-resistant (MDR) - Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae) are the main causes and have become serious problems in urinary tract infections, so antibacterial agents derived from biological materials are needed. ESBL-E. coli and ESBL-K. pneumoniae bacteria are resistant to extracts from rambutan peels and seeds, but there is no knowledge of the use of different solvents, such as n-hexane, chloroform, or ethanol. The objective of this research was to assess the antibacterial activity of rambutan peels and seed extracts (n-hexane, chloroform, and ethanol) against MDR bacteria that cause urinary tract infections (UTI). The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) values for antibacterial activity were calculated using agar well diffusion and dilution procedures. The results demonstrated that the ethanol extract of rambutan peels had inhibitory zones against MDR K. pneumoniae and E. coli that varied from 9.00 to 14.13 mm. 15.625 mg/mL For MDR E. coli and 3.90 mg/mL for MDR K. pneumoniae, respectively, the MIC value was determined. The MBC value was 62.50 mg/mL for MDR K. pneumoniae and 31.25 mg/mL for MDR E. coli. Conclusion: Of the six rambutan peel and seed extracts, the ethanol extract has greater potential as an antibacterial agent. It is advised that more in-vivo studies be done to understand how the antibacterial activity operates.The benefits of research for the science are providing alternative solutions to antibiotic resistance, to further advancing the field of antimicrobial research, and reducing the risk of bacterial infections.

Antibacterial Activity and Mechanism of Polygonatum sibiricum Extract Against Bacillus cereus and Its Application in Pasteurized Milk.

The purpose of this study was to reveal the antibacterial activity and mechanism of Polygonatum sibiricum extract (PSE) against Bacillus cereus and further analyze the application of PSE in pasteurized milk (PM). The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values and growth curve analysis were used to evaluate the antibacterial activity of PSE against B. cereus. The changes in contents of intracellular adenosine 5'-triphosphate (ATP) and reactive oxygen species (ROS), activities of β-galactosidase, adenosine triphosphatase (ATPase) and alkaline phosphatase (AKP), cell membrane potential, protein and nucleic acid leakage, and cell morphology were used to reveal the antibacterial mechanism. The effects of PSE on viable count and sensory evaluation of PM during storage were analyzed. The results showed that the MIC and MBC values of PSE against B. cereus were 2 and 4 mg/mL, respectively. Growth curve analysis showed that PSE with a concentration of 2 MIC could completely inhibit the growth of B. cereus. After treatments with PSE, the levels of intracellular ATP and ROS, and activities of β-galactosidase, ATPase and AKP of B. cereus were significantly reduced (p < 0.05). Cell membrane was depolarized, amounts of protein and nucleic acid leakage were significantly increased (p < 0.05), and cell morphology was destroyed. Furthermore, PSE significantly reduced the viable count of B. cereus in PM and improved the sensory quality of PM during storage (p < 0.05). Together, our findings suggested that PSE had the desired effect as a natural preservative applied in PM.

Characteristics of Vibrio cholerae isolates obtained from shrimp supply chains and inhibitory activities of rambutan (Nephelium lappaceum L. cv. Rong Rian) peel aqueous extract

Vibrio cholerae is a significant seafood-borne pathogen that carries multiple virulence genes. Its ability to form biofilm on surfaces enables this pathogen to persist in the environments and resistant to chemicals and antibiotics. This study investigated the virulence properties of V. cholerae isolates obtained from shrimp supply chains and evaluated the inhibitory activities of rambutan (Nephelium lappaceum L. cv. Rong Rian) peel extract (RPE) against V. cholerae and its biofilm. A total of 46 V. cholerae were isolated and most isolates harbored vasH (T6SS) (96%) and hlyA El Tor (91%) genes. Other virulence genes including stn/sto, vcsV2 (T3SS), and tcp classical genes were detected in 9, 9, and 4% of the isolates, respectively. More than 50% of the isolates produced strong biofilms and exhibited resistant against 2 or more antibiotics. RPE exhibited good activity against all isolates with the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values ranging between 2048 and 4096 and 4096 to 8192 μg/ml, respectively. Killing effect of RPE against a representative isolate V. cholerae PSU6072 was dose− and time−dependent. Transmission electron microscopy (TEM) showed that RPE effect V. cholerae cell morphology, as well as loss of cell wall were observed. At sub−MIC, RPE could reduce the swimming motility, decrease biofilm formation and disperse pre−formed biofilm of V. cholerae PSU6072. A significant down regulation of genes involved in V. cholerae quorum sensing regulator (luxO), swimming motility (flaA), and biofilm formation (vpsL, vpsR, bap1, and rbmA) was observed. In addition, a marked decrease in total aerobic bacteria and Vibrio spp. was found in shrimp meat after treatment with the RPE for short period (3 min). Thus, the results of present study strengthen the potential applications of RPE as anti−bacterial and anti−biofilm agents against V. cholerae and other bacteria contaminated in shrimp.

Study of antimicrobial efficacy of garlic oil loaded ethosome against clinical microbial isolates of diverse origin

IntroductionGarlic oil (GO), a steam-distilled product of Garlic (Allium sativum) has been successfully used as an antiseptic, antimicrobial, antioxidant and anti-inflammatory agent for decades. However, the contact irritation and volatility are practical limitations in their use. This study aimed to evaluate the in-vitro antimicrobial efficacy of garlic oil (GO) encapsulated ethosome against the microbial isolates of diverse origins as well as the effect of the storage temperature on antimicrobial efficacy. MethodsThe GO ethosomes were prepared by cold method and characterised for particle size distribution, morphology by Scanning Electron Microscopy (SEM) and molecular fingerprinting by Fourier-transform infrared spectroscopy (FT-IR) and release kinetics. ResultsThe GO ethosomes at a concentration of 25 µg/ml was found effective against all tested isolates, whereas at a concentration of 12.5 µg/ml and 6.25 µg/ml it was found effective against 146/147 and 139/147 isolates respectively. The average zone of inhibition (ZI) was 33.5 mm (25 µg/ml), 30.1 mm (12.5 µg/ml) and 24.0 mm (6.25 µg/ml). The minimum inhibitory concentration (MIC) values remain relatively constant against reference strain S. aureus (ATCC 29312 and ATCC 43300) and E. coli (NDM) at 0 days to 265 days. The minimum bactericidal concentration (MBC) values against the majority of isolates were in the range of 125–250 µg/ml. The in-vitro release data showed zero order kinetics, and best-fit release model was Korsmeyer-peppas and Weibull. ConclusionThe study demonstrated that the encapsulation of GO preserves the antimicrobial efficacy and storage for 265 days at room temperature did not alter the efficacy, suggesting wider applications in therapeutics to food preservation.

The clove essential oil and its combination with galangal oil exhibit antibacterial activity, potential as antiseptic agent

Essential oils are known and have been tested for their antimicrobial properties. Previous studies have tested the antimicrobial activity of clove and galangal essential oils alone. Thus, the purpose of this study was to determine the antimicrobial activity of clove and galangal essential oils alone as well as their combinations. The screening of antimicrobial activity was performed by disc diffusion assay against Gram-positive bacteria and Gram-negative bacteria. Both essential oils showed antimicrobial activity against Escherichia coli at 10% (v/v) concentration. Furthermore, five combinations of clove and galangal essential oils were made and tested at 1:1, 7:3, 9:1, 3:7, and 1:9 ratio. Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of three combinations with the highest activity were performed against Escherichia coli. The MIC and MBC of clove oil is at 2.5% (v/v) and 5% (v/v) while the MIC and MBC of Galangal oil is at 5% (v/v) and 10% (v/v). All three combinations showed MIC and MBC value is at 5% (v/v) and 10% (v/v) respectively. In addition, based on SNI EN 1276:2019 assay, the clove and galangal essential oil as well as their combinations meet the requirement as antiseptic agent against E. coli.

Litsea glaucescens Kuth possesses bactericidal activity against Listeria monocytogenes.

Litsea glaucencens Kuth is an aromatic plant used for food seasoning food and in Mexican traditional medicine. Among, L. glaucencens leaves properties, it has proven antibacterial activity which can be used against opportunistic pathogens like Listeria monocytogenes, a foodborne bacteria that is the causal agent of listeriosis, a disease that can be fatal in susceptible individuals. The aim of this work was to investigate the antibacterial activity of L. glaucescens Kuth leaf extracts against L. monocytogenes and to identify its bioactive components. L. glaucences leaves were macerated with four solvents of different polarity (n-hexane, dichloromethane, ethyl acetate, and methanol). To determine the capacity to inhibit bacterial proliferation in vitro, agar diffusion and microdilution methods were used. Next, we determined the minimal bactericidal concentration (MBC). Finally, we determined the ratio of MBC/MIC. Metabolites present in the active methanolic extract from L. glaucescens Kuth (LgMeOH) were purified by normal-phase open column chromatography. The structure of the antibacterial metabolite was determined using nuclear magnetic resonance (1H, 13C, COSY, HSQC) and by comparison with known compounds. The LgMeOH extract was used to purify the compound responsible for the observed antimicrobial activity. This compound was identified as 5,7-dihydroxyflavanone (pinocembrin) by analysis of its spectroscopic data and comparison with those described. The MIC and MBC values obtained for pinocembrin were 0.68 mg/mL, and the ratio MBC/MIC for both LgMeOH and pinocembrin was one, which indicates bactericidal activity. L. glaucences Kuth leaves and its metabolite pinocembrin can be used to treat listeriosis due the bactericidal activity against L. monocytogenes.

Electrospun PVA Nanofibers Loaded with Antimicrobial Herbal Extracts for Healing the Infectious Wound

Background: Low-cost, soluble polyvinyl alcohol (PVA) polymers enhance the efficacy of herbal formulations with established antimicrobial properties. Objectives: This study investigates the healing process of Staphylococcus aureus (S. aureus)-infected wounds using PVA loaded with herbal extracts, including Arnebia euchroma, Allium sativum, and Echinacea purpurea. Methods: minimal bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) assays, Disk Diffusion Method (DDM) tests, and Gas Chromatography-Mass Spectrometry (GC/MS) analyses were conducted on herbal extract samples. Twelve male Wistar rats were divided into G1: Negative control group (healthy mice), G2: Wound model + S. aureus (Positive control), G3: wound model + S. aureus + Povidone-iodine, and G4: Wound model + S. aureus + PVA/formulation. Hematoxylin-eosin and immunofluorescent staining were employed to assess wound healing. Results: The ethanolic herbal extract exhibited potent antibacterial activity against S. aureus, with MIC and MBC values in the 1.87 mg/mL range. The PVA/formulation displayed a zone of inhibition with a diameter of 7 mm against S. aureus. Histopathological investigations indicated that the infected wound treated with Nanofibers extract experienced a significant reduction in inflammation between days 7 and 14. Notably, the increased CD3 expression at this site was remarkable for the healing process. Conclusions: Consequently, this experimental study suggests combining PVA and herbal extracts enhances antibacterial properties and promotes CD3 expression and re-epithelialization effects.