Growth Inhibition Zone Research Articles

Chemical constituents of the roots of Kniphofia schimperi and evaluation of their antimicrobial activity

Kniphofia schimperi is one of the endemic plants of Ethiopia and is widely used for the treatment of microbial infections. However, the biological and phytochemical information pertaining to this plant has not been reported so far. Anticipated by these claims, the chromatographic isolation of the CHCl3/CH3OH (1:1 v/v) extract of the roots of K. schimperi afforded five compounds, viz., knipholone (1), asphodeline (2), β-sitosterol (3), 9-pentacosenoic acid (4), and nonacosanoic acid (5). The structures of the isolated compounds were identified based on their NMR (1D and 2D) spectral data analysis and comparison with reported literature data. The crude extract and isolated compounds were evaluated for their in vitro antimicrobial activity against four bacterial strains (Escherichia coli, Salmonella typhimurium, Staphylococcus aureus, and Bacillus cereus) and a fungal strain (Candida albicans) using the agar disk diffusion method. The test samples showed moderate antimicrobial activity, with the highest activity observed for compound 3 (with a zone of growth inhibition of 15.5 ± 0.71 mm) against S. typhimurium.

In English

Artificial implants are a favorable environment for bacterial adhesion and subsequent biofilm formation, thereby accelerating the development of infection in the area of implant incorporation. Despite significant progress in the development of various endoprostheses over the past decades, bacterial periprosthetic infection is one of the main factors leading to complications in their use, prolongation of rehabilitation, and significant economic losses. The present work is devoted to the creation of hybrid hydrogel nanocomposites with complex antimicrobial action for endoprosthetics in the maxillofacial region and for filling postoperative cavities (primarily after tumor removal). These nanocomposites were created on the basis of pre-synthesized spongy polyvinylformal with encapsulated gold nanoparticles, the pore space of which was partially filled with pH-sensitive hydrogels based on acrylic acid (or copolymers based on acrylamide and acrylic acid) with sorbed Albucid. The structure of the synthesized hybrid hydrogel materials was confirmed by IR spectroscopy. Studies of the kinetics of hydrogel swelling in buffer solutions with different pH values have shown that the sample filled with a copolymer of acrylamide and acrylic acid with their ratio 95:5 has the optimal properties for preserving the geometric dimensions of the material for endoprosthetics, while in the case of incorporation of 100 % acrylic acid, the degree of swelling of the material (and, respectively, its dimensions) can vary significantly with a change of рН. Antimicrobial effect of the developed hybrid hydrogel materials was investigated using the following bacterial cultures: Escherichia coli ATCC 25922, Enterococcus faecalis ATCC 29213, Staphylococcus aureus ATCC 25923, and Pseudomonas aeruginosa ATCC 27853. The antibacterial effect of polyvinylformal-based composites with incorporated gold nanoparticles that were saturated with Albucid on all test microorganisms was demonstrated (growth inhibition zones ranged from 15 to 35 mm), which will prevent microbial contamination of the developed hybrid hydrogel material when it is used in endoprosthesis.

Impact of gamma irradiation on phytochemical composition, and biological activities of Lepidium sativum seeds extract

Abstract The main objective of this research is to assess how gamma radiation influences the chemical composition and activities such as antioxidant, antimicrobial and anticancer activities of Lepidium sativum (L. sativum) seeds. Methanolic extracts were obtained through a 24 h maceration process from L. sativum seeds exposed to various doses of gamma irradiation. Phytochemical screening involved precipitation and staining reactions, with the antioxidant potential assessed using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay. Antimicrobial activity was evaluated through a diffusion test on agar medium, while the cytotoxic potential on the lung cancer line “A-549 cells” was examined using the 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Qualitative analysis of the extracts identified preserved bioactive constituents after irradiation. Additionally, quantitative analysis indicated a significant rise in the total content of polyphenols and flavonoids under radiation, accompanied by an enhanced reducing power compared to the control. The antimicrobial and cytotoxic capabilities also improved, evident in increased growth inhibition zones for certain microbial strains and reduced viability rates of A549 cells. These results show promise and warrant further investigation into the potential of gamma radiation to enhance additional biological effects of plants.

In Vitro Profiling of Potential Fish Probiotics, Enterococcus hirae Strains, Isolated from Jade Perch, and Safety Properties Assessed Using Whole Genome Sequencing.

The demands of intensified aquaculture production and escalating disease prevalence underscore the need for efficacious probiotic strategies to enhance fish health. This study focused on isolating and characterising potential probiotics from the gut microbiota of the emerging aquaculture species jade perch (Scortum barcoo). Eighty-seven lactic acid bacteria and 149 other bacteria were isolated from the digestive tract of five adult jade perch. The screening revealed that 24 Enterococcus hirae isolates inhibited the freshwater pathogens Aeromonas sobria and Streptococcus iniae. Co-incubating E. hirae with the host gut suspensions demonstrated a two- to five-fold increase in the size of growth inhibition zones compared to the results when using gut suspensions from tilapia (a non-host), indicating host-specificity. Genome analysis of the lead isolate, E. hirae R44, predicted the presence of antimicrobial compounds like enterolysin A, class II lanthipeptide, and terpenes, which underlay its antibacterial attributes. Isolate R44 exhibited desirable probiotic characteristics, including survival at pH values within the range of 3 to 12, bile tolerance, antioxidant activity, ampicillin sensitivity, and absence of transferable antimicrobial resistance genes and virulence factors commonly associated with hospital Enterococcus strains (IS16, hylEfm, and esp). This study offers a foundation for sourcing host-adapted probiotics from underexplored aquaculture species. Characterisation of novel probiotics like E. hirae R44 can expedite the development of disease mitigation strategies to support aquaculture intensification.

3D-printing of alginate/gelatin scaffold loading tannic acid@ZIF-8 for wound healing: In vitro and in vivo studies

In the present study, ZIF-8 metal-organic framework (MOF) modified with Tannic acid (TA@ZIF-8) was synthesized and impregnated in alginate-gelatin (Alg-Gel) hydrogel. The Alg-Gel scaffolds containing 0, 5, and 10 % of TA@ZIF-8 were fabricated through the 3D printing method specifically denoted as Alg-Gel 0 %, Alg-Gel 5 %, and Alg-Gel 10 %. XRD, FTIR, FESEM, and EDX physically and chemically characterized the synthesized ZIF-8 and TA@ZIF-8 MOFs. Besides, Alg-Gel containing TA@ZIF-8 prepared scaffolds and their biological activity were also evaluated. SEM images verified the nano-size formation of MOFs. Improved swelling and decreased degradation rates after adding TA@ZIF-8 were also reported. Increased compression strength from 0.628 to 1.63 MPa in Alg-Gel 0 % and Alg-Gel 10 %, respectively, and a 2.19 increase in elastic modulus in Alg-Gel 10 % scaffolds were exhibited. Biological activity of scaffolds, including Live-dead and Cell adhesion, antibacterial, in-vivo, and immunohistochemistry assays, demonstrated desirable fibroblast cell proliferation and adhesion, increased bacterial growth inhibition zone, accelerated wound closure and improved expression of anti-inflammatory cytokines in Alg-Gel 10 % scaffolds. The findings of this study confirm that Alg-Gel 10 % scaffolds promote full-thickness wound healing and could be considered a potential candidate for full-thickness wound treatment purposes.

Antibacterial Properties and Shear Bond Strength of Titanium Dioxide Nanoparticles Incorporated into an Orthodontic Adhesive: A Systematic Review.

The present review was conducted to test whether the addition of titanium dioxide (TiO2) nanoparticles (NPs) within orthodontic bracket adhesives would alter their properties and assess their antimicrobial activity against cariogenic microorganisms in addition to noteworthy mechanical properties. Using predetermined inclusion criteria, an electronic search was conducted using Dissertations and Thesis Global, the Web of Science, Cochrane, Scopus, and Medline/PubMed. Specific terms were utilized while searching the database. Only seven of the 10 included studies assessed shear bond strength (SBS). The mean SBS among the control group varied from 9.43 ± 3.03 MPa to 34.4 ± 6.7 MPa in the included studies, while in the experimental group, it varied from 6.33 ± 1.51 MPa to 25.05 ± 0.5 MPa. Antibacterial activity was assessed in five of the 10 included studies using TiO2 NPs, which could easily diffuse through bacterial media to form the growth inhibition zone. Antibacterial NPs added to orthodontic adhesives at a concentration of 1-5 wt% inhibit bacterial growth and have no effect on bond strength. D Tivanani MVD, Mulakala V, Keerthi VS. Antibacterial Properties and Shear Bond Strength of Titanium Dioxide Nanoparticles Incorporated into an Orthodontic Adhesive: A Systematic Review. Int J Clin Pediatr Dent 2024;17(1):102-108.

The Biological Active Substances of Taraxacum officinale and Arctium lappa from the Siberian Federal District.

Currently, scientists are increasingly focusing on utilizing the natural flora of the planet to search for and isolate individual bioactive substances that prevent various diseases, contribute to increased life expectancy, and affect all major life-supporting systems in the human body. This study describes the examination of the composition of plant raw materials from the Siberian Federal District. The research focuses on plant specimens from the root parts of Taraxacum officinale and Arctium lappa, collected in the Kemerovo region. The study determines the contents of the water-soluble vitamins B and C in the research subjects. The investigation includes assessing antioxidant properties, antimicrobial activity, and flavonoid content in extracts based on plant raw materials. All samples show a high percentage of antioxidant activity, with the highest antioxidant activity for T. officinale at 85.51 and that for A. lappa at 88.97. The results indicate low antimicrobial activity against Escherichia coli (growth inhibition zone up to 15.5 mm). Plant extracts contain significant amounts of B-group vitamins, with pyridoxine in T. officinale (156.40 μg/mL) and thiamine (46.20 μg/mL) and pyridoxine (357.10 μg/mL) in Arctium lappa. Flavonoids (rutin and quercetin) are identified in T. officinale and A. lappa extracts based on the study results.

Cationized gelatin-sodium alginate polyelectrolyte nanoparticles encapsulating moxifloxacin as an eye drop to treat bacterial keratitis

A mucoadhesive polyelectrolyte complex (PEC) nanoparticles were developed for ocular moxifloxacin (Mox) delivery in Bacterial Keratitis (BK). Moxifloxacin-loaded G/CG-Alg NPs were prepared by an amalgamation of cationic polymers (gelatin (G)/cationized gelatin (CG)), and anionic polymer (sodium alginate (Alg)) along with Mox respectively. Mox@CG-Alg NPs were characterized for physicochemical parameters such as particle size (DLS technique), morphology (SEM analysis), DSC, XRD, encapsulation efficiency, drug loading, mucoadhesive study (by texture analyzer), mucin turbidity, and viscosity assessment. The NPs uptake and toxicity of the formulation were analyzed in the Human Corneal Epithelial (HCE) cell line and an ocular irritation study was performed on the HET-CAM. The results indicated that the CG-Alg NPs, with optimal size (217.2 ± 4 nm) and polydispersity (0.22 ± 0.05), have shown high cellular uptake in monolayer and spheroids of HCE. The drug-loaded formulation displayed mucoadhesiveness, trans-corneal permeation, and sustained the release of the Mox. The anti-bacterial efficacy studied on planktonic bacteria/biofilms of P. aeruginosa and S. aureus (in vitro) indicated that the Mox@CG-Alg NPs displayed low MIC, higher zone of bacterial growth inhibition, and cell death compared to free Mox. A significant reduction of bacterial load was observed in the BK-induced mouse model.

Antimicrobial activity of tea processing effluents collected from various Kenyan factories

The escalating global challenge of antibiotic resistance demands exploration into alternative sources for antimicrobials. This study investigated the often-overlooked tea waste samples generated during tea processing from Kenyan processing factories to uncover novel resources containing potent and effective antimicrobial compounds. In this study, we collected tea waste samples from various tea processing factories in Kenya and assessed their antimicrobial activity against various microorganisms using the disk diffusion assay. To quantify the efficacy of each sample, we determined growth inhibition zones and minimum inhibitory and bactericidal concentrations (MICs and MBCs). The study unveiled diverse levels of antimicrobial activity in tea waste samples against specific microorganisms. Notably, the fluff sample from Gitambo factory demonstrated potent antibacterial effects against Clostridium disporicum. Various samples exhibited a moderate response to both Streptococcus pyogenes and Escherichia coli, yet they showed minimal to no activity, where applicable, towards Staphylococcus aureus and Candida albicans. This study showed that some tea effluents, which are often discarded during processing, show antimicrobial potential, as they demonstrated efficacy against certain pathogens. By further optimizing our handling and storage practices, we could enhance the isolation of potent antimicrobial compounds from these materials; this would provide valuable alternatives in combating antibiotic resistance.

Antibacterial and anthelmintic activities of Xanthium strumarium (Asteraceae) extracts

Plants of the Asteraceae family are broadly used against microorganisms pathogenic to people and animals, although their potential has not been studied completely so far. In an in vitro experiment, we tested ethanolic, ethyl-ether, and dimethyl-sulfoxide extracts from the fruits, leaves, shoots, and roots of Xanthium strumarium L. for their effects on 13 species of bacteria and larvae of 3 species of nematodes. Over-8-mm-wide growth-inhibition zones of the colonies around disks saturated with ethanolic extracts from the fruits were observed for 11 bacteria: Enterobacter cloacae, Klebsiella pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, K. aerogenes, Salmonella enterica, Escherichia coli, Morganella morganii, Enterococcus faecalis, E. faecium, Staphylococcus aureus, and Bacillus subtilis. Ethanol extract from the leaves inhibited growth of the colonies of 10 bacteria: E. cloacae, K. pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, S. enterica, E. coli, Proteus vulgaris, E. faecalis, E. faecium, S. aureus, and B. subtilis. Ethanol extract from the stem inhibited growth of the colonies of only 6 bacteria: K. aerogenes, E. cloacae, P. vulgaris, E. faecium, S. aureus, and B. subtilis. Ethanol extract from the root inhibited growth of 10 bacteria: E. cloacae, K. pneumonia ssp. rhinoscleromatis, K. pneumonia ssp. ozaenae, K. aerogenes, S. enterica, E. coli, Pseudomonas aeruginosa, E. faecalis, E. faecium, and S. aureus. We analyzed the effects of extracts based on ethyl ether and dimethyl sulfoxide, finding no antiparasitic activity or expressed anthelmintic properties of various extracts from the fruits, leaves, stem, and roots of X. strumarium against larvae of the nematodes Strongyloides papillosus, Haemonchus contortus, and Muellerius capillaris.

Phytochemical Characterization, Antimicrobial Activity, Pharmacokinetic,in silicoMolecular Docking and Interaction Analysis of Ajwa (Phoenix dactyliferaL.) Palm Date Seeds

BackgroundThere is growing evidence that antibiotic resistance is increasing. As a result, the efficacy of these antibiotics is gradually declining. This poses a serious health risk in terms of treatment strategies. Therefore, the scientific community is continuously putting all efforts into looking for novel and green therapeutics to overcome the problem of antibiotic resistance.ObjectivesThe aim of this study is to investigate the chemical composition of the methanolic extracts obtained from Phoenix dactylifera seeds, known agricultural waste, to identify new bioactive compounds and to examine the antibacterial and antifungal potentials.Materials and MethodsPhytochemical profiling was performed by the gas chromatography-mass spectrometry (GC-MS) technique. For the antibacterial activity of the methanolic extract, 12 microorganisms were selected, including eight bacteria ( Escherichia coli ATCC 35218, Pseudomonas aeruginosa ATCC 27853, Enterobacter cloacae, Enterococcus faecium, Staphylococcus hominis, Staphylococcus aureus, Staphylococcus epidermidis, and Klebsiella pneumoniae ATCC 27736) and four Candida species (C. albicans ATCC 10231, C. tropicalis ATCC 1362, C. utilis ATCC 9255, and C. guilliermondii ATCC 6260). The antimicrobial activity of the plant extract was supported by in silico molecular docking analysis.ResultsThe obtained results from the GC-MS technique revealed the presence of 51 compounds, of which 6-octadecenoic acid (Z) was identified as the major component. The tested extract exhibited the highest zone of inhibition against S. aureus (growth inhibition zone 14.66 ± 0.57 mm). In addition, minimal inhibitory concentration (MIC) and minimal bactericidal concentration values obtained against S. aureus were 1.4 and 5.6 mg/mL, respectively. Regarding the antifungal assay, C. albicans was the most sensitive one to the extract among all the tested Candida strains (14.33 mm) (MIC: 1.4 mg/mL, minimal fungicidal concentration (MFC): 11.2 mg/mL). The binding free energies and root mean square deviation values obtained from the interaction of phytochemicals with two different target receptors (1JIJ and 2QZW for TyrRS from S. aureus and aspartic proteinase from C. albicans) were also determined. Ergost-5-en-3-ol, (3beta) established hydrogen, electrostatic, alkyl, and pi-alkyl interactions with five different amino acid residues (Asp40, Asp80, Pro53, His50, and Phe54) located at the TyrRS receptor of S. aureus. On the other hand, hexadecanoic acid and methyl ester established hydrogen, electrostatic, pi-sigma, and alkyl interactions with five different amino acid residues (Thr222, Asp86, Asp218, Tyr84, and Ile123) located at the aspartic proteinase receptor of C. albicans. These interactions contributed to the stability of the complex and, hence, to the biological activity of the P. dactylifera compounds.ConclusionOur results highlighted that methanolic extract from date seeds can be a natural source of chemical compounds with promising antibacterial and antifungal activities, as demonstrated using both in vitro and in silico approaches.

Obtaining Edible Pullulan-based Films with Antimicrobial Properties

A nutrient medium was selected for the efficient production of exopolysaccharide (EPS) by A. pullulans C7 strain. The production of pullulan polysaccharide was evaluated on nutrient media with traditional carbon sources and cheap substrates that were plant wastes. For maximum EPS accumulation, we proposed an optimized Czapek-Dox medium with glucose as a carbon source, sodium nitrate as a nitrogen source, and C/N=232:1 ratio (EPS yield 12.79±0.64 g/l). Medium with grape pomace 5% (EPS yield was 15.08±0.34 g/l) and medium with topinambour tuber hydrolysate 5% (EPS yield was 14.44±0.21 g/l) was proposed as a cheap substrate. Edible films with antimicrobial activity were obtained on the basis of the isolated polysaccharide. The antibacterial activity of films against Escherichia coli 603 and Staphylococcus aureus ST228 was shown when essential oils of rosemary (zones of growth inhibition from 8.41±0.71 to 9.98±0.32 mm) and oregano (zones of growth inhibition from 8.09±0.51 to 9.54±0.24 mm) were added to pullulan. The addition of xanthan gum and glycerol to the films increased their strength and elasticity. The infrared spectrum of the pullulan film showed absorption bands characteristic of polysaccharide structures.

Utilization of nanotechnology and experimental design in the development and optimization of a posaconazole‒calendula oil nanoemulgel for the treatment of mouth disorders.

Introduction: Essential oil‒based nanoemulsions (NEs) are the subjects of extensive investigation due to their potential to address a variety of oral health issues. NEs are delivery systems that improve lipid medicine solubility and distribution to intended sites. The goal of the current study was to create and enhance a self-nanoemulsifying drug delivery paradigm based on calendula oil (CO) and decorated with chitosan (CS) that could deliver posaconazole (PSZ) for the treatment of gingivitis. Method: Employing a response-surface Box‒Behnken design, PSZ-CO-CS NEs were created with varying amounts of PSZ (10, 15, and 20mg), percentages of CO (6%, 12%, and 18%), and percentages of CS (0.5%, 1.5%, and 2.5%). Results and conclusion: The optimized formulation resulted in a 22-mm bacterial growth suppression zone, 25-mm fungal growth inhibition zone, droplet sizes of 110nm, and a viscosity of 750 centipoise (cP). Using the appropriate design, the ideal formulation was produced; it contained 20mg of PSZ, 18% of CO, and 1.35% of CS. Furthermore, the optimal formulation had a more controlled drug release, larger inhibition zones of bacterial and fungal growth, and desirable rheologic properties. Additionally, the optimized formulation substantially lowered the ulcer index in rats when tested against other formulations. Thus, this investigation showed that PSZ-CO-CS NEs could provide efficient protection against microbially induced gingivitis.

Spray-Dried Mucoadhesive Re-dispersible Gargle of Chlorhexidine for Improved Response Against Throat Infection: Formulation Development, In Vitro and In Vivo Evaluation.

Drug delivery to the buccal mucosa is one of the most convenient ways to treat common mouth problems. Here, we propose a spray-dried re-dispersible mucoadhesive controlled release gargle formulation to improve the efficacy of chlorhexidine. The present investigation portrays an approach to get stable and free-flowing spray-dried porous aggregates of chlorhexidine-loaded sodium alginate nanoparticles. The ionic gelation technique aided with the chlorhexidine's positive surface charge-based crosslinking, followed by spray drying of the nanoparticle's dispersion in the presence of lactose- and leucine-yielded nano-aggregates with good flow properties and with a size range of about 120-350nm. Provided with the high entrapment efficiency (87%), the particles showed sustained drug release behaviors over a duration of 10h, where 87% of the released drug got permeated within 12h. The antimicrobial activity of the prepared formulation was tested on S. aureus, provided with a higher zone of growth inhibition than the marketed formulation. Aided with an appropriate mucoadhesive strength, this product exhibited extended retention of nanoparticles in the throat region, as shown by in vivo imaging results. In conclusion, the technology, provided with high drug retention and extended effect, could be a potential candidate for treating several types of throat infections.

The Effect of Chlorogenic Acid in Green Arabica Coffee Beans on the Activity of Staphylococcus aureus

Background: Gingivitis is a dental and oral health problem caused by the bacteria Staphylococcus aureus. This research utilized the antibacterial effect of the chlorogenic acid compound content of green Arabica coffee beans (Coffea arabica L.) on the activity of the Staphylococcus aureus bacteria. The aim of the research was to determine the effect of chlorogenic acid from green Arabica coffee beans and its inhibitory diameter on the activity of Staphylococcus aureus bacteria.
 Methods: The research method used was laboratory experimental with post-test only with a control group design. The research samples were green Arabica coffee bean extract with various concentrations of 25%, 50%, 75%, and 100%, which is compared to various concentrations of pure chlorogenic acid (95% Sigma-Aldrich). The chlorogenic acid content in the extract was analyzed with liquid chromatography LC-MS/MS. The large sample was determined using the Federer formula with a total sample size of 24 samples. The parameter measured was the diameter of the growth inhibition zone for Staphylococcus aureus bacteria. Data were analyzed statistically using One-way ANOVA and Post Hoc LSD, and the research results were shown in regression graphs.
 Results: The results of the analysis of chlorogenic acid content of green arabica coffee bean extract amounted to 4.29% The results of this study showed that the average diameter of the inhibition zone of green Arabica coffee bean extract with concentrations of 25%, 50%, 75% and 100% on the growth of Staphylococcus aureus bacteria was 7.65 ± 0.289 mm; 9.63 ± 0.550 mm, 10.50 ± 0.374 mm, and 12.75 ± 0.370 mm. Research shows that the higher the concentration of green Arabica coffee bean extract, the larger the diameter of the inhibition zone. 95% pure chlorogenic acid from Sigma-Aldrich displays an inhibition zone above 12.5%.
 Conclusion: Chlorogenic acid exerts a substantial inhibitory impact on the proliferation of Staphylococcus aureus bacteria.

Effectiveness of white tea-mediated silver nanoparticles as an intracanal irrigant against Enterococcus faecalis: An in vitro study.

The probability of a positive outcome of root canal therapy is substantially higher if the infection is eradicated successfully before the obturation of the root canal system. Irrigation is an essential aspect of root canal debridement, as it enables more thorough cleaning than is possible with root canal instrumentation alone. To overcome the side effects of chemical irrigants, there has been a search for herbal medicines as substitutes. The aim of the present study was to explore the antimicrobial efficacy of white tea-mediated silver nanoparticles (AgNPs) formulated as an intracanal irrigant against Enterococcus faecalis, and to compare it with the efficacy of chlorhexidine and sodium hypochlorite irrigants. The experimental groups were as follows: group I - white tea-mediated AgNPs; group II - 2% chlorhexidine; and group III - 2.5% sodium hypochlorite. The characterization of AgNPs was performed using ultraviolet-visible (UV-Vis) spectroscopy and transmission electron microscopy (TEM) analysis. Enterococcus faecalis was inoculated onto Mueller-Hinton agar plates. The disks impregnated with irrigants were placed on the inoculated plates and incubated aerobically at 37°C for 24 h. Then, the growth inhibition zones were measured. Statistical analysis was performed using the one-way analysis of variance (ANOVA) and the post hoc tests. A concentration of 50 μL of white tea-mediated AgNPs exhibited the greatest zone of inhibition (32 ±2 mm), followed by 2% chlorhexidine (25 ±1 mm) and 2.5% sodium hypochlorite (23 ±3 mm). White tea-mediated AgNPs showed promising results in the elimination of E. faecalis, being superior to chlorhexidine and sodium hypochlorite irrigants.

BmPGPR-L4 is a negative regulator of the humoral immune response in the silkworm Bombyx mori.

Toll, immune deficiency and prophenoloxidase cascade represent vital immune signaling pathways in insects. Peptidoglycan recognition proteins (PGRPs) are innate immune receptors that activate and regulate the immune signaling pathways. Previously, we reported that BmPGPR-L4 was induced in the silkworm Bombyx mori larvae by bacteria and peptidoglycan challenges. Here, we focused on the function of BmPGRP-L4 in regulating the expression of antimicrobial peptides (AMPs). The hemolymph from BmPGRP-L4-silenced larvae exhibited an enhanced inhibitory effect on the growth of Escherichia coli, either by growth curve or inhibitory zone experiments. Coincidentally, most of the AMP genes were upregulated after RNAi of BmPGRP-L4. Oral administration of heat-inactivated E. coli and Staphylococcus aureus after RNAi of BmPGRP-L4 resulted in the increased expression of BmPGRP-L4 in different tissues of the silkworm larvae, revealing an auto-regulatory mechanism. By contrast, the expression of most AMP genes was downregulated by oral bacterial administration after RNAi of BmPGRP-L4. The above results demonstrate that BmPGRP-L4 recognizes bacterial pathogen-associated molecular patterns and negatively regulates AMP expression to achieve immunological homeostasis. As a negative regulator, BmPGPR-L4 is proposed to be involved in the feedback regulation of the immune signaling pathways of the silkworm to prevent excessive activation of the immune response.

Antimicrobial activity of lipids extracted from Hermetia illucens reared on different substrates

As the problem of antimicrobial resistance is constantly increasing, there is a renewed interest in antimicrobial products derived from natural sources, particularly obtained from innovative and eco-friendly materials. Insect lipids, due to their fatty acid composition, can be classified as natural antimicrobial compounds. In order to assess the antibacterial efficacy of Hermetia illucens lipids, we extracted this component from the larval stage, fed on different substrates and we characterized it. Moreover, we analyzed the fatty acid composition of the feeding substrate, to determine if and how it could affect the antimicrobial activity of the lipid component. The antimicrobial activity was evaluated against Gram-positive Micrococcus flavus and Gram-negative bacteria Escherichia coli. Analyzing the fatty acid profiles of larval lipids that showed activity against the two bacterial strains, we detected significant differences for C4:0, C10:0, C16:1, C18:3 n3 (ALA), and C20:1. The strongest antimicrobial activity was verified against Micrococcus flavus by lipids extracted from larvae reared on strawberry, tangerine, and fresh manure substrates, with growth inhibition zones ranged from 1.38 to 1.51 mm, while only the rearing on manure showed the effect against Escherichia coli. Notably, the fatty acid profile of H. illucens seems to not be really influenced by the substrate fatty acid profile, except for C18:0 and C18:2 CIS n6 (LA). This implies that other factors, such as the rearing conditions, larval development stages, and other nutrients such as carbohydrates, affect the amount of fatty acids in insects.Key points• Feeding substrates influence larval lipids and fatty acids (FA)• Generally, there is no direct correlation between substrate FAs and the same larvae FAs• Specific FAs influence more the antimicrobial effect of BSF lipidsGraphical abstract

Nanoapatite-Loaded κ-Carrageenan/Poly(vinyl alcohol)-Based Injectable Cryogel for Hemostasis and Wound Healing.

Immediate control of excessive bleeding and prevention of infections are of utmost importance in the management of wounds. Cryogels have emerged as promising materials for the rapid release of medication and achieving hemostasis. However, their quick release properties pose the challenge of exposing patients to high concentrations of drugs. In this study, hybrid nanocomposites were developed to address this issue by combining poly(vinyl alcohol) and κ-carrageenan with whitlockite nanoapatite (WNA) particles and ciprofloxacin, aiming to achieve rapid hemostasis and sustained antibacterial effects. A physically cross-linked cryogel was obtained by subjecting a blend of poly(vinyl alcohol) and κ-carrageenan to successive freezing-thawing cycles, followed by the addition of WNA. Furthermore, ciprofloxacin was introduced into the cryogel matrix for subsequent evaluation of its wound healing properties. The resulting gel system exhibited a 3D microporous structure and demonstrated excellent swelling, low cytotoxicity, and outstanding mechanical properties. These characteristics were evaluated through analytical and rheological experiments. The nanocomposite cryogel with 4% whitlockite showed extended drug release of 71.21 ± 3.5% over 21 days and antibacterial activity with a considerable growth inhibition zone (4.19 ± 3.55 cm). Experiments on a rat model demonstrated a rapid hemostasis property of cryogels within an average of 83 ± 4 s and accelerated the process of wound healing with 96.34% contraction compared to the standard, which exhibited only ∼78% after 14 days. The histopathological analysis revealed that the process of epidermal re-epithelialization took around 14 days following the skin incision. The cryogel loaded with WNAs and ciprofloxacin holds great potential for strategic utilization in wound management applications as an effective material for hemostasis and anti-infection purposes.

The chemical composition, in vitro, and in silico studies of Lavandula mairei essential oil

Lavandula mairei is an aromatic, and medicinal plant endemic to Morocco, mainly found in the southeastern region of the Kingdom, and used in traditional medicine for its many benefits. The purpose of the study was to identify the chemical composition of Lavandula mairei essential oil using Gas Chromatography - Tandem Mass Spectrometry, to evaluate the antimicrobial activity of the plant against bacterial strains (Staphylococcus aureus, Staphylococcus aureus MRSA, Enterococcus faecalis, Escherichia coli ATCC 25922, Escherichia coli ESBL, Klebsiella pneumoniae ATCC 700603), and two fungal strains (Aspergillus niger ATCC 10231, Candida albicans ATCC 16404) in order to measure the microbial growth inhibition zone diameter, and to determine the minimum inhibitory, bactericidal, and fungicidal concentration of the essential oil (MIC, MBC, and MFC). Concerning antioxidant activity, six assays (6DPPH, and 1ABTS Free Radical Scavenging Assay, Total Antioxidant Capacity, Hydroxyl Radical, Reducing Power, and β-Carotene Bleaching Inhibition) were performed to determine the antioxidant potential of the essential oil. For the in silico aspect, molecular docking studies were performed to explore the potential interactions of some compounds with five microbial targets (i) Dihydropteroate synthase (1AJ0), ii) The elongation factor EF-Tu (1OB2), iii) d-alanine ligase (2I80), iv) DNA gyrase (2XCT), v) The cytochrome P450 monooxygenase (5V5Z), and 2ADMET prediction analysis was completed on a compound designated as dehydroabietinol. Carvacrol was identified as the major compound (36.38%) by analysis of the chemical composition, E. coli ATCC 25922 (MIC = 1.87 mg/mL ± 0.00, MBC = 15.00 mg/mL ± 0.00), and Enterococcus faecalis (MIC = 0.23 mg/mL ± 0.00, MBC = 5.53 mg/mL ± 2.77) were the most sensitive to the antibacterial treatment, and Candida albicans was resistant to the essential oil. The highest antioxidant potential of the plant was observed in the β-carotene bleaching inhibition test (IC50 = 1.55 mg/mL ± 0.009 and 90 % of inhibition). In the in silico study, the compound dehydroabietinol provided relevant evidence for molecular docking, and this was confirmed by the ADMET prediction analysis. The results of the study were significant, and further experiments will be necessary to find out more about the biological properties of Lavandula mairei.