Minimum Inhibitory Concentration Values Research Articles

The Comparative Study of the Antioxidant and Antibacterial Effects of Propolis Extracts in Veterinary Medicine.

Antimicrobial resistance (AMR) is one of the biggest threats to human and animal health. Efforts to combat AMR include the introduction of antimicrobial drugs as alternative treatment options. To contribute to an effective plan for the treatment of infectious diseases caused by bacteria, the development of new antimicrobial agents is increasingly being explored. Propolis has garnered significant attention from both scientists and industry due to its extensive spectrum of biological activity. The growing interest in polyphenols of natural origin and their plant sources further encourages the investigation of their chemical composition and biological effects. Propolis serves as a rich source of phenolic compounds. Baltic region propolis, classified as poplar-type propolis, was selected for this study, and extracts were prepared using raw propolis materials from various Baltic countries. The production of liquid extracts utilized a combination of 70 percent ethanol, a mixture of water and poloxamer P407, and DES (deep eutectic solvent). The research aims to produce liquid propolis extracts using different solvents and to assess their chemical composition, antioxidant, and antimicrobial activity against different veterinary pathogens. Antioxidant activity was evaluated using DPPH (2,2-diphenyl-1-picrylhydrazyl), revealing antioxidant activity in all extracts, with results correlating with the total phenolic compound content. It was found that p-coumaric acid predominated in the studied propolis extracts (in ethanol extracts 1155.90-1506.65 mg/g, in DES extracts 321.13-954.76 mg/g, and in polymeric extracts 5.34-30.80 mg/g), with smaller amounts of ferulic acid and vanillin detected. Clinical and reference bacterial strains were collected from the Lithuanian University of Health Sciences, the Academy of Veterinary Medicine, and the Institute of Microbiology and Virology. To effectively treat bacterial infections, the antimicrobial activity of propolis extracts was tested against six pathogenic bacterial species and one pathogenic fungus (S. aureus, S. agalactiae, B. cereus, E. faecalis, E. coli, P. aeruginosa, and C. albicans). Antimicrobial activity studies demonstrated that DES propolis extracts exhibited stronger antimicrobial activity compared to ethanolic propolis extracts. The minimum inhibitory concentration (MIC) values of DES propolis extracts against the tested strains ranged between 50 and 1000 μg/mL. Considering the study results, it can be concluded that propolis from the Baltic region is abundant in phenolic compounds exhibiting antioxidant and antibacterial activities.

Fabrication of smart nanogel based on carrageenan and green coffee extract as a long-term antifouling agent to improve biofilm prevention in food production

This study investigates the extract of the bioactive compounds from green coffee extract (GCE) and the loading of two different concentrations of GCE (1% and 2%) onto carrageenan nanogels (CAR NGs) to compare their antibacterial and antibiofilm effects with unloaded nanogels (NGs). The bioactive compounds of GCE were characterized using GC–MS analysis. The GCE1 and GCE2 were successfully deposited onto the surface of CAR NGs. The antibacterial and antibiofilm potential of prepared NGs were conducted against some foodborne pathogens (E. coli O157, Salmonella enterica, Staphylococcus aureus, and Listeria monocytogenes). The results of GC–MS analysis indicated that there were identified 16 bioactive compounds in GCE, including caffeine (36.27%), Dodemorph (9.04%), and D-Glycero-d-ido-heptose (2.44%), contributing to its antimicrobial properties. The antibacterial coatings demonstrated a notable antimicrobial effect, showing zone of inhibition (ZOI) diameters of up to 37 mm for GCE2 loaded CAR NGs. The minimum inhibitory concentration (MIC) values for GCE2 loaded CAR NGs were 80 ppm for E. coli O157, and 120 ppm for S. enterica, S. aureus, and L. monocytogenes, achieving complete bacterial inactivation within 10–15 min of exposure. Both GCE1 and GCE2 loaded CAR NGs significantly reduced biofilm cell densities on stainless steel (SS) materials for E. coli O157, S. enterica, S. aureus, and L. monocytogenes, with reductions ranging from 60% to 95%. Specifically, biofilm densities were reduced by up to 95% for E. coli O157, 89% for S. enterica, 85% for S. aureus, and 80% for L. monocytogenes. Results of the toxicity evaluation indicated that the NGs were non-toxic and biocompatible, with predicted EC50 values proved their biocompatibility and safety. These results recommended that GCE loaded CAR NGs are promising as natural antimicrobial agents for enhancing food safety and extending shelf life. Further, the study concluded that incorporating GCE into CAR NGs is an effective strategy for developing sustainable antimicrobial coatings for the food industry and manufacturing.

Evaluation of the antibacterial activity of pineapple (Ananas comosus) (L.) Merr. industrial waste against common fish and shellfish pathogens

Disposal of industrial pineapple (Ananas comosus) wastes is a pressing environmental issue due to pollution risks when accumulated in large quantities. These wastes are susceptible to microbial spoilage, posing serious environmental and health concerns. Therefore, exploring their conversion into valuable products is crucial for effective waste management. In this study, we assessed the antibiotic properties of pineapple processing wastes against prevalent fish pathogens in aquaculture. The wastes underwent various drying methods: sun-drying (SD), oven-drying (OD), and mechanical dehydration (DH). Ethanol extraction was used to isolate bioactive compounds, which were then tested for antibacterial activity at a concentration of 1000 mg/ml using the Agar Well Diffusion technique and Zone of Inhibition (ZOI) assay. Minimum Inhibitory Concentration (MIC) values were determined across six concentrations: 31.25 mg/ml, 62.50 mg/ml, 125 mg/ml, 250 mg/ml, 500 mg/ml, and 1000 mg/ml. Results indicated that all extracts from different drying processes effectively inhibited all tested aquaculture pathogens. DH extracts showed the highest antibacterial activity against Vibrio harveyi and Vibrio parahaemolyticus, with ZOI of 24.67 + 1.25 mm and 21.67 + 0.47 mm, respectively, and a consistent MIC of 250 mg/ml across all pathogens. SD extracts displayed a MIC of 125 mg/ml against Streptococcus agalactiae, while OD extracts showed a MIC of 1000 mg/ml against Edwardsiella tarda, Aeromonas veronii, and S. agalactiae, and 250 mg/ml against both Vibrio species. Comparative analysis with oxytetracycline did not reveal significant differences. These findings suggest that pineapple waste extracts have potential as natural antibacterial agents against common aquaculture pathogens, offering an eco-friendly alternative to commercial antibiotics.

Peptide PaDBS1R6 has potent antibacterial activity on clinical bacterial isolates and integrates an immunomodulatory peptide fragment within its sequence

BackgroundResistant infectious diseases caused by gram-negative bacteria are among the most serious worldwide health problems. Antimicrobial peptides (AMPs) have been explored as promising antibacterial, antibiofilm, and anti-infective candidates to address these health challenges. Major conclusionsHere we report the potent antibacterial effect of the peptide PaDBS1R6 on clinical bacterial isolates and identify an immunomodulatory peptide fragment incorporated within it. PaDBS1R6 was evaluated against Acinetobacter baumannii and Escherichia coli clinical isolates and had minimal inhibitory concentration (MIC) values from 8 to 32 μmol L−1. It had a rapid bactericidal effect, with eradication showing within 3 min of incubation, depending on the bacterial strain tested. In addition, PaDBS1R6 inhibited biofilm formation for A. baumannii and E. coli and was non-toxic toward healthy mammalian cells. These findings are explained by the preference of PaDBS1R6 for anionic membranes over neutral membranes, as assessed by surface plasmon resonance assays and molecular dynamics simulations. Considering its potent antibacterial activity, PaDBS1R6 was used as a template for sliding-window fr agmentation studies (window size = 10 residues). Among the sliding-window fragments, PaDBS1R6F8, PaDBS1R6F9, and PaDBS1R6F10 were ineffective against any of the bacterial strains tested. Additional biological assays were conducted, including nitric oxide (NO) modulation and wound scratch assays, and the R6F8 peptide fragment was found to be active in modulating NO levels, as well as having strong wound healing properties. General significanceThis study proposes a new concept whereby peptides with different biological properties can be derived by the screening of fragments from within potent AMPs.

Expression of Caseicin from Lacticaseibacillus casei and Lacticaseibacillus zeae Provides Insight into Antilisterial Class IIa Bacteriocins.

In this study, an in silico screening approach was employed to mine potential bacteriocin clusters in genome-sequenced isolates of Lacticaseibacillus zeae UD 2202 and Lacticaseibacillus casei UD 1001. Two putative undescribed bacteriocin gene clusters (Cas1 and Cas2) closely related to genes encoding class IIa bacteriocins were identified. No bacteriocin activity was recorded when cell-free supernatants of strains UD 2202 and UD 1001 were tested against Listeria monocytogenes. Genes encoding caseicin A1 (casA1) and caseicin A2 (casA2) were heterologously expressed in Escherichia coli BL21 (DE3) using the nisin leader peptide cloned in-frame to the C-terminal of the green fluorescent gene (mgfp5). Nisin protease (NisP) was used to cleave caseicin A1 (casA1) and caseicin A2 (casA2) from GFP-Nisin leader fusion proteins. Both heterologously expressed peptides (casA1 and casA2) inhibited the growth of L. monocytogenes, suggesting that casA1 and casA2 are either silent in the wild-type strains or are not secreted in an active form. The minimum inhibitory concentration (MIC) of casA1 and casA2, determined using HPLC-purified peptides, ranged from < 0.2µg/mL to 12.5µg/mL when tested against Listeria ivanovii, Listeria monocytogenes, and Listeria innocua, respectively. A higher MIC value (25µg/mL) was recorded for casA1 and casA2 when Enterococcus faecium HKLHS was used as the target. The molecular weight of heterologously expressed casA1 and casA2 is 5.1 and 5.2kDa, respectively, as determined with tricine-SDS-PAGE. Further research is required to determine if genes within Cas1 and Cas2 render immunity to other class IIa bacteriocins.

Predicting antimicrobial properties of lignin derivatives through combined data driven and experimental approach

Meta-analysis, experimental and data-driven quantitative structure–activity relationship (QSAR) models were developed to predict the antimicrobial properties of lignin derivatives. Five machine learning algorithms were applied to develop QSAR models based on the ChEMBL, a public non-lignin specific database. QSAR models were refined using ordinary-least-square regressions with a meta-analysis dataset extracted from literature and an experimental dataset. The minimum inhibition concentration (MIC) values of compounds in the meta-analysis dataset correlate to classification-based descriptors and the number of aliphatic carboxylic acid groups (R2 = 0.759). Comparatively, QSARs derived from the experimental datasets suggest that the number of aromatic hydroxyl groups were better predictors of Bacterial Load Difference (BLD, R2 = 0.831) for Bacillus subtilis, while the number of alkyl aryl groups were the strongest correlation in predicting the BLD (R2 = 0.682) of Escherichia coli. This study provides insights into the type of descriptors that correlate to antimicrobial activity and guides the valorization of lignin into sustainable antimicrobials for potential applications in food preservation, fermentation, and other industrial sectors.

Ru-terpyridine complexes containing clotrimazole as potent photoactivatable selective antifungal agents

The overuse of antimicrobial agents in medical and veterinary applications has led to the development of antimicrobial resistance in some microorganisms and this is now one of the major concerns in modern society. In this context, the use of transition metal complexes with photoactivatable properties, which can act as drug delivery systems triggered by light, could become a potent strategy to overcome the problem of resistance. In this work several Ru complexes with terpyridine ligands and the clotrimazole fragment, which is a potent antimycotic drug, were synthesized. The main goal was to explore the potential photoactivated activity of the complexes as antifungal agents and evaluate the effect of introducing different substituents on the terpyridine ligand. The complexes were capable of delivering the clotrimazole unit upon irradiation with visible light in a short period of time. The influence of the substituents on the photodissociation rate was explained by means of TD-DFT calculations. The complexes were tested against three different yeasts, which were selected based on their prevalence in fungal infections. The complex in which a carboxybenzene unit was attached to the terpyridine ligand showed the best activity against the three species under light, with minimal inhibitory concentration values of 0.88 μM and a phototoxicity index of 50 achieved. The activity of this complex was markedly higher than that of free clotrimazole, especially upon irradiation with visible light (141 times higher). The complexes were more active on yeast species than on cancer cell lines.

Fabrication and optimization of naringin-loaded MOF-5 encapsulated by liponiosomes as smart drug delivery, cytotoxicity, and apoptotic on breast cancer cells

Introduction Cancers are regarded as hazardous due to their high worldwide death rate, with breast cancer (BC), which affects practically all cancer patients globally, playing a significant role in this statistic. The therapeutic approach for BC has not advanced using standard techniques, such as specialized naringin (NG) chemotherapy. Instead, a novel strategy has been utilized to enhance smart drug delivery (SDD) to tumors. Significance Herein, we established NG-loaded zinc metal-organic framework-5 (NG-MOF-5) coated with liponiosomes (LNs) to manufacture NG-MOF-5@LNs nanoparticles (NPs) for antibacterial and cancer treatment. Methods MOF-5, NG, and NG-MOF-5@LNs were evaluated with XRD, thermogravimetric analysis (TGA), FTIR, SEM, TEM, PDI, ZP, encapsulation efficiency (EE), loading efficiency (LE), and drug release (DR) kinetics. We examined the antibacterial activity involving minimum inhibitory concentration (MIC) and zone of inhibition by NG, MOF-5, and NG-MOF-5@LNs. The cell viability, necrosis, and total apoptosis (late and early) were evaluated for anti-cancer activity against MCF-7 BC cells. Results TEM results demonstrated that NG-MOF-5@LNs formed monodispersed spherical-like particles with a size of 122.5 nm, PDI of 0.139, and ZP of +21 mV. The anti-microbial activity results indicated that NG-MOF-5@LNs exhibited potent antibacterial effects, as evidenced by inhibition zones and MIC values. The Higuchi model indicates an excellent fit (R 2 = 0.9988). The MTT assay revealed anti-tumor activity against MCF-7 BC cells, with IC50 of 21 µg/mL for NG-MOF-5@LNs and demonstrating a total apoptosis effect of 68.2% on MCF-7 cells. Conclusion NG-MOF-5@LNs is anticipated to show as an effective antimicrobial and novel long-term-release antitumor agent and might be more suitable for MCF-7 cell therapy.

Synergistic effect of phenylpropanoids and flavonoids with antibiotics against Gram-positive and Gram-negative bacterial strains

Context The increase in bacterial resistance to currently available medications, which increases mortality rates, treatment costs is a global problem, and highlights the need for novel classes of antibacterial agents or new molecules that interact synergistically with antimicrobials. Objective The current work explores the potential synergistic effects of certain natural phenylpropanoids and flavonoids on ciprofloxacin (CIP), ampicillin (AMP), gentamicin (GEN), and tetracycline (TET). Materials and methods The adjuvant role of cinnamic acid, p-coumaric acid, caffeic acid, ferulic acid, ferulic acid methyl ester, sinapic acid, apigenin, and luteolin was evaluated by determining the MIC (minimal inhibitory concentration) values of antibiotics in the presence of subinhibitory concentrations (200, 100, and/or 50 µM) of the compounds in Gram-positive and Gram-negative bacterial strains using a 2-fold broth microdilution method. The 96-well plates were incubated at 37 °C for 18 h, and dimethyl sulfoxide was used as a solvent control. Results The combination of luteolin with CIP, reduced the MIC values of the antibiotic from 0.625 to 0.3125 µM and to 0.078 µM in 100 and 200 µM concentration, respectively, in sensitive Staphylococcus aureus. Sinapic acid decreased the MIC value of CIP from 0.625 to 0.3125 µM in S. aureus, from 1.56 to 0.78 µM in Klebsiella pneumoniae, and the MIC of GEN from 0.39 to 0.095 µM in Pseudomonas aeruginosa strains. Discussion and conclusions These findings are useful in delaying the development of resistance, as the required antibacterial effect can be achieved with the use of lower concentrations of antibiotics.

Phenanthrenes from Juncus articulatus with Antibacterial and Biofilm Formation Inhibitory Activity.

Continuing our search for bioactive compounds in species from the Juncaceae family, Juncus articulatus was investigated. Ten previously undescribed phenanthrenes─articulins A-J (1-10)─and ten known compounds─juncuenin B, dehydrojuncuenin B, juncatrin B, ensifolins E, F, H, I, K, juncuenin D, and luzulin A (11-20)─along with other compounds, have been isolated and identified. The isolated compounds were evaluated for antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, methicillin-susceptible Staphylococcus aureus (MSSA), and methicillin-resistant Staphylococcus aureus (MRSA). Compounds 12 and 14 exhibited the most potent activity against planktonic and sessile MSSA and MRSA with minimum inhibitory concentration (MIC) values of 15.1 μM (12 for both bacterial strains) and 15.3 μM (14 for both bacterial strains). Compounds 15, 17, and 18 also exhibited activity against both strains, although to a lower extent, with MIC values ranging from 30.0 to 56.8 μM. The inhibition of biofilm formation of these compounds was observed at 15.1-114.3 μM. This study elucidates the phenanthrene composition of J. articulatus and the antibacterial effect of these compounds.

Breaking Down the Barriers of Drug Resistance and Corneal Permeability with Chitosan-Poly(ethylene glycol)-LK13 Peptide Conjugate to Combat Fungal Keratitis.

Fungal keratitis (FK) is a leading cause of preventable blindness and eye loss. The poor antifungal activity, increased drug resistance, limited corneal permeability, and unsatisfactory biosafety of conventional antifungal eye drops are among the majority of the challenges that need to be addressed for currently available antifungal drugs. Herein, this study proposes an effective strategy that employs chitosan-poly(ethylene glycol)-LK13 peptide conjugate (CPL) in the treatment of FK. Nanoassembly CPL can permeate the lipophilic corneal epithelium in the transcellular route, and its hydrophilicity surface is a feature to drive its permeability through hydrophilic stroma. When encountering fungal cell membrane, CPL dissembles and exposes the antimicrobial peptide (LK13) to destroy fungal cell membranes, the minimum inhibitory concentration values of CPL against Fusarium solani (F. solani) are always not to exceed 8 μg peptide/mL before and after drug resistance induction. In a rat model of Fusarium keratitis, CPL demonstrates superior therapeutic efficacy than commercially available natamycin ophthalmic suspension. This study provides more theoretical and experimental supports for the application of CPL in the treatment of FK.

Plasmid-mediated azithromycin resistance in non-typhoidal Salmonella recovered from human infections.

Mechanisms of non-typhoidal Salmonella (NTS) resistance to azithromycin have rarely been reported. Here we investigate the epidemiology and genetic features of 10 azithromycin-resistant NTS isolates. A total of 457 NTS isolates were collected from a tertiary hospital in Guangzhou. We performed antimicrobial susceptibility tests, conjugation experiments, efflux pump expression tests, whole-genome sequencing and bioinformatics analysis to conduct the study. The results showed that 10 NTS isolates (2.8%) were resistant to azithromycin with minimum inhibitory concentration values ranging from 128 to 512 mg/L and exhibited multidrug resistance. The phylogenetic tree revealed that 5 S. London isolates (AR1-AR5) recognized at different times and departments were closely related [3-74 single-nucleotide polymorphisms (SNPs)] and 2 S. Typhimurium isolates (AR7 and AR8) were clones (<3 SNPs) at 3-month intervals. The azithromycin resistance was conferred by mph(A) gene found on different plasmids, including IncFIB, IncHI2, InFII, IncC and IncI plasmids. Among them, IncFIB, InFII and IncHI2 plasmids carried different IS26-class 1 integron (intI1) arrangement patterns that mediated multidrug resistance transmission. Conjugative IncC plasmid encoded resistance to ciprofloxacin, ceftriaxone and azithromycin. Furthermore, phylogenetic analysis demonstrated that mph(A)-positive plasmids closely related to 10 plasmids in this study were mainly discovered from NTS, Escherichia coli, Klebsiella pneumonia and Enterobacter hormaechei. The genetic environment of mph(A) in 10 NTS isolates was IS26-mph(A)-mrx(A)-mphR(A)-IS6100/IS26 that co-arranged with intI1 harbour multidrug-resistant (MDR) gene cassettes on diverse plasmids. These findings highlighted that the dissemination of these plasmids carrying mph(A) and various intI1 MDR gene cassettes would seriously restrict the availability of essential antimicrobial agents for treating NTS infections.

Antileishmanial and Antifungal Activities of Volatile Oils from Cinnamomum Cassia Bark and Schinus Molle Leaves.

This study reports on the chemical composition and antileishmanial and anticandidal activities of volatile oils (VOs) of Schinus molle dried leaves (SM), Cinnamomum cassia branch bark (CC) and their blends. Major constituents of SM were spathulenol (26.93 %), β-caryophyllene (19.90 %), and caryophyllene oxide (12.69 %), whereas (E)-cinnamaldehyde (60.11 %), cinnamyl acetate (20.90 %) and cis-2-methoxycinnamic acid (10.37 %) were predominant in CC. SM (IC50=21.45 μg/mL) and CC (IC50=23.27 μg/mL) displayed good activity against L. amazonensis promastigotes, besides having good or moderate activity against nine Candida strains, with Minimum Inhibitory Concentration (MIC) values ranging from 31.25 to 250 μg/mL. While the three SM and CC blends were not more active than the VOs tested individually, they exhibited remarkably high antileishmanial activity, with IC50 values ranging between 3.12 and 7.04 μg/mL, which is very similar to the IC50 of amphotericin B (positive control).

THE POTENCY OF CINNAMON (Cinnamomum burmanni Blume) LEAF EXTRACT AS A BIOPRESERVATIVE AGENT FOR FOOD SAFETY OF SATE LILIT

ARTICLE HIGLIGHTS- Cinnamon leaf extract combats E. coli in traditional Balinese food.- Natural preservative reduces harmful pathogens in sate lilit.- Cinnamon extract offers a safer alternative to synthetic preservatives.- Active compounds in cinnamon leaves inhibit bacterial growth.- Effective biopreservative for enhancing food safety and quality. ABSTRACTEscherichia coli O157:H7 contamination of the meat used in preparing sate lilit, a favorite traditional food in Bali, Indonesia, has been a great concern for both local people and foreigners. Although C. burmanni has been included in its spice ingredients, active compounds that play a significant role in this pathogen have limitedly been elucidated. The main objectives of this research were to investigate the potency of this plant to control contaminants and elucidate possible compounds that prevent such contaminants by applying the disk diffusion method and LCMS analysis, respectively. The results showed that the leaf extract of this plant inhibited the in vitro growth of E. coli O157:7, with minimal inhibitory concentration (MIC) and LC50 values of 4% and 2.59%, respectively. The LCMS analysis chromatogram showed that the plant extract's most active fraction produced nine peaks, representing nine possible active compounds. Among those, three compounds (Azoxystrobin, Stigmatellin Y, and 2-arachidonoyl glycerol) were suspected of contributing to control contamination, especially by E. coli O157:H7.

Trematocine-derived antimicrobial peptides from the Antarctic fish Trematomus bernacchaii: potent antibacterial agents against ESKAPE pathogens.

This study investigated the interaction with membrane mimetic systems (LUVs), bacterial membranes, the CD spectra, and the bactericidal activity of two designed trematocine mutants, named Trem-HK and Trem-HSK. Mutants were constructed from the scaffold of Trematocine (Trem), a natural 22-amino acid AMP from the Antarctic fish Trematomus bernacchii, aiming to increase their positive charge. The selectivity of the designed AMPs towards bacterial membranes was improved compared to Trematocine, verified by their interaction with different LUVs and their membranolytic activity. Additionally, their α-helical conformation was not influenced by the amino acid substitutions. Our findings revealed a significant enhancement in antibacterial efficacy against ESKAPE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacteriaceae family) pathogens for both Trem-HK and Trem-HSK. Firstly, we showed that the selectivity of the two new designed AMPs towards bacterial membranes was greatly improved compared to Trematocine, verifying their interaction with different LUVs and their membranolytic activity. We determined that their α-helical conformation was not influenced by the amino acid substitutions. We characterized the tested bacterial collection for resistance traits to different classes of antibiotics. The minimum inhibitory and bactericidal concentration (MIC and MBC) values of the ESKAPE collection were reduced by up to 80% compared to Trematocine. The bactericidal concentrations of Trematocine mutants showed important membranolytic action, evident by scanning electron microscopy, on all tested species. We further evaluated the cytotoxicity and hemolytic activity of the mutants. At 2.5 μM concentration, both mutants demonstrated low cytotoxicity and hemolysis, indicating selectivity towards bacterial cells. However, these effects increased at higher concentrations. Assessment of in vivo toxicity using the Galleria mellonella model revealed no adverse effects in larvae treated with both mutants, even at concentrations up to 20 times higher than the lowest MIC observed for Acinetobacter baumannii, suggesting a high potential safety profile for the mutants. This study highlights the significant improvement in antibacterial efficacy achieved by increasing the positive charge of Trem-HK and Trem-HSK. This improvement was reached at the cost of reduced biocompatibility. Further research is necessary to optimize the balance between efficacy and safety for these promising AMPs.

Maleimide conjugated PEGylated liposomal antibiotic to combat multi-drug resistant Escherichia coli and Klebsiella pneumoniae with enhanced wound healing potential

Antibiotic resistance is a significant threat, leaving us vulnerable to bacterial infections. Novel strategies are needed to combat bacterial resistance beyond discovering new antibiotics. This research focuses on using maleimide conjugated PEGylated liposomes (Mal-PL-Ab) to individually encapsulate a variety of antibiotics (ceftriaxone, cephalexin, doxycycline, piperacillin, ampicillin, and ceftazidime) and enhance their delivery against multi-drug resistant (MDR) bacteria like Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae). Mal-PL-Ab, with an average size of 84.2 nm ± 4.32 nm, successfully encapsulated these antibiotics with an encapsulation efficiency of 37.73 ± 3.19%. Compared to non-PEGylated liposomes (L-Ab), Mal-PL-Ab exhibited reduced toxicity in human dermal cells, emphasizing the importance of PEGylation in minimizing adverse effects. Mal-PL-Ab significantly decreased the minimum inhibitory concentration (MIC) values against both E. coli and K. pneumoniae by 9.33-fold and eightfold reduction (compared to non-PEGylated liposomes with 2.33-fold and 2.33fold reduction), respectively, indicating enhanced efficacy against MDR strains. Furthermore, in vitro scratch assay and gene expression analysis of human dermal fibroblast revealed that Mal-PL-Ab promoted cell proliferation, migration, and wound healing through upregulation of cell cycle, DNA repair, and angiogenesis-related genes. Harnessing the power of encapsulation, Mal-PL-Ab presents a novel avenue for enhanced antibiotic delivery and wound healing, potentially transcending the limitations of traditional options.

Antibacterial activity of Monascus-fermented sorghum extracts against Staphylococcus aureus and Escherichia coli

Monascus purpureus is one of the few types of edible fungi known for their abundant bioactivity. This research was aimed to investigate the antibacterial activity of Monascusfermented sorghum extract (MFSE). Three different solvents were used for extraction: ethyl acetate, ethanol, and water. Antibacterial activity was assessed by determining minimum inhibitory concentration (MIC). The broth microdilution method was used to determine the MIC of the extract against Staphylococcus aureus and Escherichia coli. Additionally, moisture content, color, and biomass of Monascus-fermented sorghum (MFS) were analyzed, along with the pigment and total phenolic content of MFSE. All obtained data were calculated for the mean. Antibacterial activity was observed in MFSE extracted with all three solvents, displaying MIC values of 0.018, 0.216, and 0.794 mg/L against S. aureus and 0.996, 1.205, and 1.138 mg/L against E. coli for ethyl acetate, ethanol, and water extract, respectively. The MFSE extracted with ethyl acetate exhibited the lowest MIC, indicating the highest antibacterial activity.

Phytotherapeutic potential of Artemisia ludoviciana and Cordia boissieri extracts against the dermatophyte Microsporum canis

Abstract Introduction Microsporum canis is a dermatophyte that mainly affects dogs and cats. However, it can be transmitted to humans by direct contact. This makes it one of the most frequent causative agents of dermatophytosis in humans, reflecting the frequent human close relationships with pets. Conventional treatment relies on antifungal pharmacological agents. However, errors in application have led to the occurrence of fungal resistance and toxic effects. Consequently, new therapeutic alternatives are needed for M. canis infections. Plant extracts have been explored as phytotherapeutics for the treatment of dermatophyte infections, which prompted an attempt to apply extracts of the ethnopharmacologically important plants Artemisia ludoviciana and Cordia boissieri. Material and Methods Methanolic extracts of these two plants were obtained using a Soxhlet method and were characterised by phytochemical screening. Extracts were evaluated against a M. canis commercial strain (ATCC-11621) using the microdilution method described in the Clinical and Laboratory Standards Institute protocol M38-A, determining its minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC). Subsequently, these concentrations were tested in a human keratinocyte human cell line. Results Artemisia ludoviciana and C. boissieri extracts showed MIC values of 2,500 and 1,250 µg/mL, and MFC values of 5,000 and 2,500 µg/mL against M. canis, respectively. These extracts did not inhibit HaCaT cell proliferation in vitro. Conclusion The evaluated extracts showed potential for the treatment of M. canis fungal infections. However, further studies on their phytochemical characterisation, purification, clinical safety and formulation are required.

Antibacterial Activity of Cissus quadrangularis (Veldt Grape) Against Porphyromonas gingivalis, a Keystone Pathogen in Periodontal Disease: An In Vitro Study.

Porphyromonas gingivalis, a keystone pathogen and one of the primary pathogens responsible for periodontitis, leads to a chronic inflammatory condition that destroys the periodontal tissues and ultimately results in tooth loss. While conventional non-surgical therapy combined with antibiotics and local drug delivery systems are commonly used to treat periodontitis, certain medicinal herbs have also demonstrated efficacy in its prevention. Cissus quadrangularis L. (CQ), a perennial plant from the Vitaceae family, is widely recognized and used as a medicinal herb in many tropical countries, predominantly in India, Sri Lanka, Thailand, Java, West Africa, and the Philippines. The aim of the study was to determine the antibacterial activity of CQ against the periodontal keystone pathogen P. gingivalis. Aqueous and ethanolic extracts of CQ were prepared using a Soxhlet extractor. The antibacterial effectiveness of these extracts against the periodontal pathogen P. gingivalis was evaluated at different concentrations, and the minimal inhibitory concentration (MIC) was determined using broth microdilution. The ethanolic extract of CQ mixed with 10% dimethyl sulfoxide (DMSO) showed higher inhibition compared to the aqueous extract of CQ against P. gingivalis. Our study revealed the potent inhibitory effects of CQ against P. gingivalis. Both aqueous and ethanolic extracts displayed MIC values of 500 µg/mL. Notably, the ethanolic extract of CQ, dissolved in 10% DMSO, demonstrated superior efficacy with a lower IC50 value of 194.36 µg/mL. These findings indicate promising potential for CQ in the management of periodontal disease.

New Benzylidene‐Triazole Tethered Coumarin Molecular Hybrids: Synthesis, SAR, Molecular Modelling Simulations Targeting Tubulin α/β Dimer and its Antimicrobial Evaluation

AbstractA series of new 7‐{3‐[3‐(Benzylidene‐amino)‐[1,2,4]triazole‐1‐yl]‐propoxy}‐4‐methyl‐chromen‐2‐one molecular hybrids 7(a–k) were synthesized using molecular hybridization approach. The synthesized new benzylidene‐triazole tethered coumarin molecular hybrids were characterized by spectroscopic studies and elemental analysis. The coumarin molecular hybrids have been explored for their antifungal efficacy in terms of tubulin inhibitors using molecular modelling studies against tubulin alphabeta hetero dimer protein. The results clearly demonstrated strong binding affinity of coumarin molecular hybrids with indole substituted and 2,4‐dihydroxy substituted as antagonists with respective binding scores of −10.5 and −10.7 kcal/mol towards tubulin alphabeta hetero dimer protein which was higher in comparison to standards griseofulvin (−8.2 kcal/mol) and fluconazole (−8.1 kcal/mol). In addition, broth dilution method was used to conduct in‐vitro antifungal studies against three fungal strains namely Candida albicans, Aspergillus niger and Aspergillus fumigatus. The results obtained clearly illustrate the antifungal activity of indole and 2,4‐dihydroxy substituted compounds which are consistent with docking simulations. Out of all the synthesized molecular hybrids, indole and 2,4‐dihydroxy substituted compounds depict outstanding antifungal activity with Minimum Inhibitory Concentration (MIC) value of 31.25 μg/ml and 62.5 μg/ml towards C.albicans and with MIC value of 31.25 for both these molecules towards A.niger in each case which is quite higher than griseofulvin and fluconazole respectively. Present work clearly demonstrates the potential efficacy of synthesized indole and 2,4‐dihydroxy substituted coumarin molecular hybrids to be considered as lead compounds for the development of new agents against resistant strains for the treatment of fungal infection.