Gram-negative Bacterial Strains Research Articles

Isolation, characterization, and whole genome sequencing analysis of Aeromonas veronii from Channa argus in China.

Aeromonas veronii has emerged as a significant pathogen that impacts both fish and mammals. Recently, an infectious disease characterized by multiple ulcers on the body surface with a high mortality rate occurred in Channa argus cultured in Jiangsu Province, China. A Gram-negative bacterial strain (Aer12) was isolated from the body surface of the diseased fish and identified as A. veronii by the physiological, biochemical, and 16S rRNA gene analysis. Intra-peritoneal injection of Aer12 into the healthy C. argus resulted in the development of multiple ulcers on the body surface, and the histopathological results showed that muscle tissue rupture was the most severe symptom. Aer12 showed both protease and lipase activities with no β-hemolytic activity. Furthermore, Aer12 contained seven virulence genes (aer, act, alt, fla, ascV, aexT, and ela) and one antibiotic resistance gene (qnrS) identified by the PCR assay. The results of whole genome sequencing revealed that Aer12 had a circular chromosome that measured 4,719,428bp. It comprised 4301 predicted protein-coding sequences (CDS) in addition to 31 rRNA, 124 tRNA, and 49 sRNA genes. Furthermore, a total of 676 virulence genes and 216 antibiotic resistance genes have been predicted. Aer12 was susceptible to 21 antibiotics, including ampicillin and erythromycin. The results of Chinese herbs susceptibility assay showed that Aer12 was highly susceptible to Sanguisorba officinalis, Galla chinensis, and Schisandra chinensis. The results of this study will serve as a reference for future research on the pathogenic mechanism of A. veronii and the prevention and control of bacterial diseases in C. argus farming.

Development of Cyclometalated Iridium(III) Complexes of 2-Phenylbenzimidazole and Bipyridine Ligands for Selective Elimination of Gram-Positive Bacteria.

Herein, we have reported a series of cationic aggregation-induced emission (AIE) active iridium(III) complexes (Ir1-Ir5) of the type [Ir(C^N)2(N^N)]Cl, wherein C^N is a cyclometalating 2-phenylbenzimidazole ligand with varying alkyl chain lengths and N^N is a 2,2'-bipyridine ligand attached to bis-polyethylene glycol chains, for the treatment of bacterial infections. The AIE phenomenon of the complexes leveraged for detecting bacteria by fluorescence microscopy imaging that displayed a strong red emission in Gram-positive bacteria. The antibacterial activity of the complexes assessed against Gram-positive methicillin-sensitive S. aureus, methicillin-resistant S. aureus, E.faecium and E.faecalis and Gram-negative E. coli and P.aeruginosa bacteria of clinical interest. The complexes Ir2-Ir4 exerted potent antibacterial activity towards Gram-positive strains with low minimum inhibitory concentrations (MICs) values in the range of 1-9 μM, which is comparable to clinically approved antibiotic vancomycin. In contrast, these complexes were found to be inactive towards Gram-negative bacterial strains (MICs > 100 µM). The mechanism of antibacterial activity of the complexes implies that ROS generation, membrane depolarization and rupture are responsible for bacterial cell death. Further, the complexes Ir1-Ir3 were found to be low-toxic against human red blood cells and human embryonic kidney (HEK293) cells, indicating their potential for use as antibacterial agents.

Pillar[5]arene stabilized gold nanoparticles for the enhanced light-triggered nitric oxide release with antibacterial and antibiofilm activities

The reactivity of guests confined in well-defined host cavities act significantly different from that in bulk systems. In this work, pillar[5]arene not only works as a stabilizer for the fabrication of gold nanoparticles, but also act as an accelerator for the enhanced photo-triggered release of gaseous nitric oxide (NO) from encapsulated NO donor. The host–guest complex can dramatically improve the photoactivity of loaded guest molecule to generate antibacterial NO molecules through the confinement effect of pillar[5]arene cavity. The synergistic photo-triggered localized NO release and photo-thermal effect of host–guest complex demonstrated impressive antibacterial behaviors against Gram-negative bacterial strain Escherichia coli, Gram-positive bacterial strain Staphylococcus aureus and methicillin-resistant Staphylococcus aureus. Moreover, this biocompatible photo-responsive complex can also inhibit bacterial biofilm formation and disrupt the pre-existing biofilms.

Engineering of self-assembled silver-peptide colloidal nanohybrids with enhanced biocompatibility and antibacterial activity

Several bacterial strains have developed resistance against commercial antibiotics, and interestingly, supramolecular nanomaterials have shown considerable advantages for antibacterial applications. However, the main challenges in adopting nanotechnology for antibacterial studies are random aggregation, compromised toxicity, multi-step preparation approaches, and unclear structure-function properties. Herein, we designed the amphiphilic tripeptide that acts as a reducing and capping agent for silver metal to form silver-peptide colloidal nanohybrids with the mild assistance of UV light (254 nm) through the photochemical reduction method. The nanohybrids are characterized by different spectroscopic and microscopic techniques, and non-covalent molecular interactions between metal and peptide building blocks confirm their central role in the formation of nanohybrids. The tripeptide is biocompatible and can reduce the toxicity of silver ions (Ag+) by reducing to Ag0. These colloidal nanohybrids showed antibacterial activity against gram-negative and gram-positive bacterial strains, and the possible mechanism of killing bacterial cells could be membrane disruption. This synthetic strategy is facile and green, which helps avoid using toxic chemicals or reagents and complicated methods for colloidal nanohybrid preparation for biomedical applications.

Carbapenem resistance in gram-negative pathogens in an Iranian hospital: high prevalence of OXA-type carbapenemase genes.

The widespread dissemination of carbapenem-resistant Gram-negative bacteria poses a significant threat to global public health. This study aimed to investigate the prevalence of carbapenem resistance in Gram-negative bacteria isolated from patients at the Children's Medical Center Hospital, Tehran, Iran, to understand the molecular mechanisms underlying this resistance. During the period spanning from June 2019 to June 2020, 777 Gram-negative bacterial strains were isolated. Antibiotic susceptibility testing was performed according to Clinical and Laboratory Standards Institute. Polymerase chain reaction was used to detect carbapenem resistance genes including bla OXA23, bla OXA24, bla OXA48, bla OXA51, bla OXA58, bla OXA143, bla KPC, bla IMP, bla VIM, and bla NDM. Among the total bacterial isolates, 141 (18.1%) exhibited carbapenem resistance. Escherichia coli was the most prevalent (57.4%), followed by Klebsiella pneumoniae (11.3%) and Acinetobacter baumannii (10.6%). Other notable contributors included Enterobacter spp. (5.7%), Salmonella spp. (3.5%), and Stenotrophomonas maltophilia (2.8%). Citrobacter spp., Proteus mirabilis, and Pseudomonas aeruginosa contributed to the distributions of two, one, and three isolates, respectively. Notably, bla OXA48 showed the highest prevalence (33%), followed by bla OXA143 and bla OXA58 (27% and 24%, respectively). In addition, bla OXA24 was present in 11% of the total isolates, bla OXA23 in 10%, and bla NDM in 10%, whereas bla KPC, bla VIM, and bla IMP were not detected. Our study highlights the prevalence of carbapenemase-producing Gram-negative isolates among pediatric patients. Notable resistance patterns, especially in K. pneumoniae and E. coli, underline the urgent need for proactive interventions, including appropriate antibiotic prescription practices and strengthening of antibiotic stewardship programs.

Investigation of pure and Sn-doped Ca(OH)2 nanoparticles for optical and biomedical applications

The present study explores the synthesis and characterization of pure and Sn-doped Ca(OH)2 nanoparticles, highlighting their potential for optical and biomedical applications. The incorporation of Sn into the Ca(OH)2 matrix is investigated for the first time, providing insights into its impact on the structural, optical, and biological properties of the nanoparticles. A straightforward precipitation method was employed to synthesize pure and Sn-doped calcium hydroxide nanoparticles. The synthesized nanoparticles were characterized by using X-ray diffraction (XRD) pattern, ultraviolet–visible–near infrared (UV-Vis-NIR) spectra, Fourier Scanning Electron Microscope (FESEM) micrographs, and agar well diffusion method for antibacterial study. X-ray diffraction examinations confirmed the polycrystalline nature of the Ca(OH)2 nanoparticles and revealed the structure to be hexagonal. The average crystallite size of the pure and Sn-doped Ca(OH)2 nanoparticles are 49 nm and 66 nm, respectively. The FESEM images of the sample revealed the formation of pure Ca(OH)2 nanoparticles in the form of nanoflakes and the change in the morphology while doping Sn with Ca(OH)2. The prepared samples were assessed using UV-Vis-NIR spectra, showing the UV absorption band at approximately 247 and 263 nm for the samples of pure and Sn-doped Ca(OH)2 nanoparticles, respectively. The calculated direct and indirect allowed band gap energies were found to be 4.04 and 3.92 eV for pure Ca(OH)2, and 3.37 and 2.94 eV in the case of Sn-doped Ca(OH)2. The antibacterial effectiveness of Ca(OH)2 nanoparticles was assessed using the well diffusion method, and it was observed that both the samples of pure and Sn doped Ca(OH)2 nanoparticles exhibited significant antibacterial properties against gram-negative bacterial strains. An elevation in Minimum Inhibitory Concentration (MIC) values for Sn-doped Ca(OH)2 nanoparticles compared to pure Ca(OH)2 nanoparticles was observed when examining their impact on Gram-negative bacteria (Klebsiella pneumoniae), which suggested a requirement for a higher concentration due to the nature of surface charges present in order to inhibit the growth of microorganisms.

Investigating antibacterial and anti-inflammatory properties of synthetic curcuminoids.

The concept of intratumoral microbiota is gaining attention in current research. Tumor-associated microbiota can activate oncogenic signaling pathways such as NF-κB, thereby promoting tumor development and progression. Numerous studies have demonstrated that curcumin and its analogs possess strong antitumor effects by targeting the NF-κB signaling pathway, along with potent antibacterial properties. In this study, we tested the antibacterial activity of two curcuminoids, Py-cPen and V-cPen, against the Gram-negative bacterial strains Pseudomonas aeruginosa and Escherichia coli and the Gram-positive bacterial strain Streptococcus aureus using in vitro assays and fluorescent microscopy. We observed that both Py-cPen and V-cPen reduced NF-κB activation upon lipopolysacharide (LPS) challenge in cell assays. In addition, our findings indicate that Py-cPen and V-cPen interact with LPS, as demonstrated by transmission electron microscopy and confirmed using in silico analyses, thereby modulating LPS activity. Overall, our data indicate that Py-cPen and V-cPen exhibit strong antibacterial and antiinflammatory properties, suggesting their potential as candidates for new multitarget therapeutic strategies.

Investigation of antibacterial and anticancer activities of biosynthesized metal-doped and undoped zinc oxide nanoparticles.

Over the past 10 years, nanotechnology has emerged as a very promising technique for a wide range of biomedical applications. Green synthesized metal and metal oxide nanoparticles (NPs) are cheap, easy to produce in large quantities, and safe for the environment. Currently, efforts are being made to dope ZnO in order to improve its optical, electrical, and ferromagnetic qualities as well as its crystallographic quality. Actually, doping is one of the simplest methods for enhancing an NP's physicochemical characteristics because it involves introducing impure ions into the crystal lattice of the particle. In this study, the biosynthesis of zinc oxide NPs (ZnONPs) and metal-doped (Mg2+ and Ag+) ZnONPs was carried out by using aqueous and water-alcoholic extracts of Cynara scolymus L. leaves, Carthamus tinctorius L. flowers, and Rheum ribes L. (RrL) plant, which are rich in phytochemical content. Plant extracts act as a natural reducing, capping, and stabilizing agent in the production. The produced NPs were characterized using a variety of methods, such as ultraviolet-visible spectroscopy, Fourier transform infrared (FTIR) spectroscopy, dynamic light scattering (DLS), and scanning electron microscopy (SEM). The produced metal-doped and undoped ZnONPs exhibited characteristic absorption peaks between 365 and 383nm due to their surface plasmon resonance bands. SEM analysis revealed that the NPs were oval, nearly spherical, and spherical. In the FTIR spectra, the Zn-O bonding peak ranges from 400 to 700cm-1. The peaks obtained in the range of 407-562cm-1 clearly represent the Zn-O bond. In addition, the FTIR results showed that there were notable amounts of phenol and flavonoid compounds in both the prepared extract and ZnONPs. According to DLS analysis results, the size distribution of produced NPs is between 120 and 786nm. The antibacterial properties of green produced NPs on Gram-positive (Staphylococcus aureus RN4220) and Gram-negative (Escherichia coli DH10B) bacterial strains were investigated by agar well diffusion method. In studies investigating the anticancer activities of biosynthesized NPs, mouse fibroblast cells (L929) were used as healthy cells and human cervical cancer cells (HeLa) were used as cancer cells. Only the produced Ag-ZnONPs showed potent dose-dependent antibacterial activity (at concentrations higher than 100µg/mL) against Gram-positive and Gram-negative bacteria. RrL-ZnONP-600 and RrL-ZnONP-800 NPs produced with water-ethanol extract of RrL plant and calcined at 600 and 800°C were effective at high concentrations in healthy cells and at low concentrations in HeLa cancer cells, showing that they have the potential to be anticancer agents. The study's findings highlight the potential of green synthesis techniques in the production of medicinal nanomaterials for the treatment of cancer and other biological uses.

Biofabricated silver nanoparticles from Calotropis procera: A potential antimicrobial solution against pathogenic bacteria

Calotropis procera has the potential as a traditional medicinal plant that offers a diverse array of healing treatments. It was used in conventional medicine to remedy several ailments, including diarrhea and snakebites. This study examines the antibacterial properties of silver nanoparticles derived from the floral and latex components of C. procera. The nanoparticles were tested for their effectiveness against Gram-negative and Gram-positive bacterial strains. For characterization, the synthesized nanoparticles underwent thorough analysis using UV spectroscopy, fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM). After the reduction process, the FTIR analysis revealed that some functional biomolecules found in plants form a coating on the nanoparticles, serving as organic agents that stabilize the nanoparticles. The size of nanoparticles analyzed with SEM falls in the 30 to 130 nm range. Furthermore, the synthesized silver nanoparticles were tested as antimicrobial agents against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, and Pseudomonas aeruginosa, well-known microorganisms that can produce ulceration phases and severe health consequences. After a comprehensive examination, it was found that the silver nanoparticles have significant antibacterial effectiveness, particularly against S. aureus, a primary bacterium responsible for causing different ailments. The remarkable antibacterial efficacy of the silver nanoparticles synthesized in an environment-friendly manner underscores its potential applications in combating the evolution of antibiotic-resistant strains.

Zn(II)-based mechanically flexible metallosupramolecular network: Investigating rheology, morphology, anti-bacterial effect and semiconducting device performances

Synthesis of supramolecular Zn(II)-metallogel of succinic acid with N,N′-dimethyl formamide (DMF) solvent has been explored in this present study. Succinic acid is used as a low molecular weight gelator (LMWG) and DMF acts as a metallogel-immobilized solvent-media. Mechanical flexibility, viscous, and elastic behaviours of the metallogel are characterized by exhaustive rheological experiments. Different rheological parameters like storage modulus (G′) and loss modulus (G″) are evaluated for certain regions of shear strain and angular frequency. The morphological decoration of xerogel material obtained from Zn(II)-based metallosupramolecular gel (i.e., Zn-Succinic) has been visualized through field emission scanning electron microscope (FESEM). Energy dispersive X-ray analysis (EDX) verifies the active involvement of metallogel-forming chemical constituents. The flexible metallosupramolecular scaffold-construction strategy has been unveiled through infrared spectroscopic data and ESI-Mass investigations. The antibacterial potency of Zn(II)-directed metallogel has also been verified against several Gram-positive bacteria (i.e., Bacillus cereus (ATCC 13061), Bacillus subtilis (MTCC 121), Listeria monocytogenes (MTCC 657), Staphylococcus aureus (MTCC 96)), and two Gram-negative bacterial strains (i.e., Salmonella typhimurium (MTCC 98) and Escherichia coli (MTCC 1667)). Even, Zn-Succinic metallogel exhibits Schottky diode behaviour with a significant non-linear rectifying nature in I-V curve, proving the semiconducting diode features with electrical parameters.

Facile modification of TiO2 as S-Scheme multifunctional materials for environmental protection and energy-storage applications

This paper reports a simple one-step modification of commercial TiO2 with a conducting polytrimethoxyslilypropyl aniline (PTMSPA, a polyaniline derivative having silyl networks) to have multi-functional (photocatalytic, optical, pseudocapacitive, hydrophobic, porous, antibacterial, and electromagnetic interference shielding (EMI)) properties and demonstrates associated applications. We present the S-Scheme heterojunction (SHJ) formation between TiO2 and PTMSPA through band position alignments and designate the resultant TiO2 - TiO2- based SHJ multifunctional materials as MF-TSSM. The internal electric field that is generated at the interface facilitates the transportation of the photogenerated electron transfer . The XRD pattern of MF-TSSM exhibits mainly the peaks of anatase TiO2. The TEM image of MF-TSSM indicates that the TiO2 particles are spherical in shape with sizes showing variations in diameters ranging from 60 nm to 250 nm depending on the experimental conditions of preparation and TiO2 particles are homogeneously distributed within the PTMSPA matrix. The optical energy band gap of MF-TSSM is 1.60 eV, a much lower value than PTMSPA (3.02 eV), suggesting that the composite formation between TiO2 and PTMSPA. The contact angle of MF-TSSM is significantly increased to 47.1 ° from 8.0 of TiO2, informing the increase of hydrophobic characteristics. The rate constant (k) for methylene blue photodegradation was 0.030 min-1, and 0.010 min-1 for MF-TSSM and pristine TiO2, respectively, The MF-TSSM composite exhibits a higher specific capacitance value (28.7 F/g) than TMSPA (21.1 F/g). At a frequency of 0.42 THz, MF-TSSM and PTMSPA exhibit return loss features indicating good EMI shielding performance. The MF-TSSM has been tested against two different Gram-positive and Gram-negative bacterial strains. The nanoparticles were evaluated at doses of 10, 20, 40, and 80 µg/ml. The results indicated that Klebsiella pneumoniae demonstrated a greater zone of inhibition, ranging from 9 mm at 10 µg/ml to 23 mm at 80 µg/ml, indicating increased susceptibility. Pseudomonas aeruginosa exhibited reduced inhibition zones, ranging from 10 mm at 10 µg/ml to 14 mm at 80 µg/ml, indicating increased resistance. The excellent effectiveness of MF-TSSM against various Gram-positive and Gram-negative pathogenic bacteria is explained by the interaction between reactive oxygen species and the cellular components of the bacteria as well the electrostatic interaction arising between positive charges in TMSPA and negative charges in the cell components, resulting in notable cytotoxicity and damage to the bacterial cells. The research underscores the capability of these modified TiO₂ nanoparticles in addressing bacterial infections, with efficiency differing by bacterial strain.

Structural and Biological Comparative Studies on M(II)-Complexes (M = Co, Mn, Cu, Ni, Zn) of Hydrazone-s-Triazine Ligand Bearing Pyridyl Arm

The molecular and supramolecular structures of some M(II) complexes (M = Co, Mn, Cu, Ni, Zn) with a hydrazone-s-triazine ligand (BMPyTr) were discussed based on single crystal X-ray diffraction (SCXRD), Hirshfeld and DFT analyses. A new Co(II) complex of the same ligand was synthesized and its structure was confirmed to be [Co(BMPyTr)Cl2]·H2O based on FTIR and UV–Vis spectra, elemental analysis and SCXRD. The geometry around Co(II) was a distorted square pyramidal configuration (τ5 = 0.4), where Co(II) ion is coordinated to one NNN-tridentate ligand (BMPyTr) and two Cl- ions. A Hirshfeld analysis indicated all potential contacts within the crystal structure, where the percentages of O⋯H, N⋯H, C⋯H, and H⋯H contacts in one unit were 11.2, 9.3, 11.4, and 45.9%, respectively, while the respective values for the other complex unit were 10.3, 8.8, 10.6, and 48.0%. According to DFT calculations, the presence of strongly coordinating anions, such as Cl-, in addition to the large metal ion size, were found to be the main reasons for the small M-BMPyTr interaction energies in the cases of [Mn(BMPyTr)Cl2] (260.79 kcal/mol) and [Co(BMPyTr)Cl2]·H2O (307.46 kcal/mol) complexes. Interestingly, the Co(II) complex had potential activity against both Gram-positive (S. aureus and B. subtilis) and Gram-negative (E. coli and P. vulgaris) bacterial strains with inhibition zone diameters of 13, 15, 16, and 18 mm, respectively. Also, the new [Co(BMPyTr)Cl2]·H2O (IC50 = 131.2 ± 6.8 μM) complex had slightly better cytotoxic activity against HCT-116 cell line compared to BMPyTr (145.3 ± 7.1 μM).

Antibacterial profile and antiproliferative activities over human tumor cells of new silver(I) complexes containing two distinct trifluoromethyl uracil isomers

New silver(I) complexes of 5-(trifluoromethyl)uracil (5TFMU) and 6-(trifluoromethyl)uracil (6TFMU) isomers were synthesized, characterized, and evaluated as antibacterial and antiproliferative agents. Based on elemental and thermogravimetric analyses, the Ag-5TFMU and Ag-6TFMU species are formulated as AgC5H2F3N2O2 and Ag2C5HF3N2O2, respectively. Infrared and 13C solid-state nuclear magnetic resonance spectroscopies suggest coordination of the trifluoromethyluracil isomers to silver by both nitrogen and oxygen atoms. Confirmation of their structure and connectivity was achieved, in the absence of single crystals of suitable quality, by state-of-the-art structural powder diffraction methods. In Ag-5TFMU, the organic ligand is tridentate and two distinct metal coordination environments are found (linear AgN2 as well as C2v AgO4 geometries), whereas Ag-6TFMU contains a complex polymeric structure with tetradentate dianionic 6TFMU moieties and five distinct AgX2 (X = N, O) fragments, further stabilized by ancillary (longer) Ag…O contacts. These species presented modest activity over Gram-positive and Gram-negative bacterial strains, whereas Ag-6TFMU was active over a set of tumor cells, with the best activity over prostate (PC-3) and kidney cell lines and selectivity indices of 4.6 and 1.3, respectively. On the other hand, Ag-5TFMU was active over all considered tumor cells except MCF-7 (breast cancer). The best activity was found for PC-3 cells, but no selectivity was observed. The Ag-5TFMU and Ag-6TFMU species also reduced the proliferation of tongue squamous cell carcinoma cell lines SCC − 4 and SCC-15. Preliminary biophysical assays by circular dichroism suggest that the Ag-5TFMU complex interacts with DNA by intercalation, an effect not seen in Ag-6TFMU.

Bio-synthesized AGS@AgNPs for wound healing, antioxidant support, antibacterial defense, and anticancer intervention

Slow wound healing and wound infections are significant challenges for burn patients. Biosynthesis of nanoparticles (NPs) using plant extracts offers a rapid, facile, and safe method for producing biocompatible NPs. In this study, Anethum graveolens seed (AGS) extract served as a masking and reducing agent for the synthesis of silver nanoparticles (AGS@AgNPs). Initially, the parameters influencing AGS@AgNPs synthesis, including silver nitrate concentration, reaction time, temperature, and pH, were optimized. Subsequently, AGS@AgNPs structural and biological characteristics were evaluated. Observation of the surface plasmon resonance (SPR) of the AGS@AgNPs at approximately 420 nm, accompanied by a color change of the suspension to dark brown, confirmed AGS@AgNPs synthesis. Analysis via X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), dynamic light scattering (DLS), zeta potential, and transmission electron microscopy (TEM) confirmed the production of pure, homogeneous, spherical, and stable silver NPs with sizes ranging from 20 to 40 nm using Anethum graveolens extract. Antibacterial assays revealed significant activity against both Gram-positive and Gram-negative bacterial strains. Antioxidant assessments demonstrated that AGS@AgNPs at a concentration of 250 μg/ml exhibited 92% inhibition of DPPH free radicals and in FRAP test, A. graveolens seed extract and AGS@AgNPs reduced Fe3+ ions to Fe2+ by 48.7% and 73.1%, respectively. Investigation of anticancer properties against the lung cancer cell line (A-549) revealed an IC50 value of 242 μg/ml. The results of the flow cytometry test and lactate dehydrogenase (LDH) assay demonstrated the death of cancer cells. Moreover, wound healing assays demonstrated a significant acceleration in burn wound closure rates in rats on days 3, 7, and 14 following treatments with AGS@AgNPs. Overall, these findings highlight the favorable biological activities of AGS@AgNPs, suggesting their potential utility in nanomedicine applications.

Novel Co(II), Cu(II) and Zn(II) complexes derived from thiazole containing Schiff base ligands: Green synthesis, antimicrobial and anti-cancer studies

Six novel metal complexes of Co(II), Cu(II), and Zn(II) were synthesized using a microwave-assisted method. These complexes were derived from Schiff base ligands prepared through the condensation of 4-(p-fluorophenyl)-5-methyl-2-aminothiazole with 3-methoxysalicyldehyde (L1) and 2-hydroxynaphthaldehyde (L2). Characterization techniques, including UV–vis, IR, NMR, and HR-MS confirm the tridentate nature of Co(II), Zn(II), and bidentate nature of Cu(II) complexes. Elemental and thermogravimetric analysis showed 1:2 (M: L) stoichiometry in metal complexes. Meanwhile, magnetic susceptibility and powder X-ray diffraction express the geometry and crystal systems of complexes. The antimicrobial analysis of the synthesized compounds indicates Cu(II) complexes have greater potency against gram-positive bacterial and fungal strains while Zn(II) complexes show a greater zone of inhibition against gram-negative bacterial strains. Moreover, MIC values of the most potent complexes [Cu(L2)2] and [Zn(L2)2] range from 190-375 µg/mL. Furthermore, ligands and their complexes have been tested for anticancer potential against MDA-MB 231 and A549 cell lines by MTT assay. [Zn(L1)2] and [Zn(L2)2] complexes were found to have potent activity with IC50 values of 16.7 µM, 24.1 µM, and 8.7 µM, 13.4 µM respectively on MDA-MB-231 and A549 cell lines compared to other complexes and parent ligands. Molecular docking study performed using the PyRx 0.8 (with RF-Score V2 scoring function) program against EGFR (PDB: 5XGM) showed strong binding interactions which supports the experimental results.

Synthesis and Characterization of 4-Hydroxy-3-((2-Hydroxy-3-Methoxybenzylidene)Amino)Benzenesulfonic Acid and Its Metal Complexes and their Antimicrobial Activity

Schiff base was obtained from the reaction of vanillin with 3-amino-4-hydroxybenzenesulfonic acid. Metal complexes were synthesized using (Ni(NO3)2, Co(NO3)2, Mn(NO3)2, Cu(NO3)2, Zn(NO3)2) metal salts and the structures of the compounds were elucidated by spectroscopic methods. The structures of the metal complexes were also characterized by elemental analysis, FT-IR, thermogravimetric analysis and magnetic susceptibility analysis and their antimicrobial activities were investigated. The antimicrobial activities of the obtained coordination compounds were investigated against three Gram-positive (Bacillus subtilis ATCC 6633; Staphylococcus aureus ATCC 25923; Enterococcus faecalis ATCC 29212) three Gram-negative bacterial (Escherichia coli ATCC 25922; Klebsiella pneumonia ATCC 70060; Pseudomonas aeruginosa ATCC 27853) strains and two fungal (Aspergillus niger ATCC 16404; Candida albicans ATCC 1023) strains, and the minimum inhibitory concentration (MIC) values were determined. According to the MIC values, the SC-Ni complex exhibited the highest antimicrobial activity, while the SC-Cu complex showed the lowest.

Synthesis, characterization, antibacterial, antioxidant and molecular docking studies of Zn(II) complexes with imine quinoline derivative ligand

The efficacy of metal complexes with bioactive ligands for pharmaceutical purposes is increasingly gaining clinical and commercial importance for treating infectious diseases. This research aimed to synthesize new Zn(II) complexes, assess their potential applications in antibacterial and antioxidant properties, and explore their molecular docking properties. The synthesis was done by condensing 7-chloro-2-hydroxyquinoline-3-carbaldehyde and 2,2′-thiodianiline with Zn(II) metal complexes. A range of spectroscopic techniques, such as 1H and 13C NMR, FTIR, TG/DTA, pXRD, and UV–Vis, were employed to characterize both the ligand and its complexes. Imine quinoline ligand (L), ZnL, and ZnL2 all had average crystallite diameters of 13.28, 21.19, and 16.26 nm, respectively, according to pXRD analysis, which confirmed that the synthesized ligand and its Zn(II) complexes showed polycrystalline properties. Based on the results, an octahedral geometry was proposed for the complexes. A very good agreement was obtained between the experimental and the TD-DFT calculated absorption peaks. Their biological potency against Gram-positive (Staphylococcus aureus ATCC 25926) and Gram-negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 248) bacterial strains as well as antioxidant properties were tested. The ZnL complex showed a maximum growth inhibition of 9.50 ± 0.41 mm against S. aureus ATCC 25926; whereas the maximum growth inhibition of the ZnL2 complex was 9.67 ± 0.47 mm and 9.33 ± 0.47 mm against ATCC 25926, respectively. With an IC50 of 167.3 ± 1.04 mg/mL, ZnL had the strongest antioxidant activity against DPPH radicals. All the complexes had strong binding affinities according to the molecular docking investigation: L (−11.31 kcal/mol), ZnL (−11.38 kcal/mol), and ZnL2 (−13.51 kcal/mol) against the active sites of S. aureus and (−7.92, −8.07, and −8.92) kcal/mol, respectively, against the active sites of E. coli. The Zn(II) complexes had the highest potency of biological activity.

Biogenic Synthesis, Optimization, and characterization of zinc oxide nanoparticles using Rumex abyssinicus Jacq root extract for antioxidant and antibacterial activities

Nanoparticles may be synthesized through chemical, physical, and biological strategies, but the former strategies contain critical troubles, including environmental toxicity and cost-effectiveness. This work addresses adopting a green synthesis method for ZnO NPs using Rumex abyssinicus Jacq root extract for antibacterial and antioxidant programs. A UV–vis spectrophotometer optimized various factors, including temperature, pH, time, zinc acetate dihydrate attention, and the volume ratio of zinc acetate dihydrate to plant root extract. The biosynthesized ZnO NPs had been examined using exclusive characterization instrunments. ZnO NPs and Rumex abyssinicus Jacq root extract confirmed enormous inhibitory effects on pathogenic bacterial lines, inclusive of the gram-negative bacterial strains Escherichia coli and Staphylococcus typhi and the gram-positive bacterial pressure Staphylococcus aureus. ZnO NPs and Rumex abyssinicus Jacq root extract exhibited the best antioxidant sports. consequently, this has a look at confirmed that Rumex abyssinicus Jacq root extract is an effective decreasing agent for the synthesis of ZnO NPs, which exhibit antibacterial and antioxidant activities.

Antimicrobial and Enzymatic Activities of Mangrove-associated Actinomycetes

This study delves into the enzymatic and antimicrobial capabilities of actinomycetes isolated from the Setiu Wetland mangrove in Terengganu, Malaysia. A total of eighteen actinomycete bacteria were isolated and characterized from the site. These isolates underwent antimicrobial assessments targeting a representative range of Gram-positive bacteria, Gram-negative bacteria and a fungus were employed for the testing. The results of the antimicrobial evaluations demonstrated pronounced effectiveness of the majority of isolated actinomycetes against Gram-negative bacterial strains. Intriguingly, a notable observation was the inhibition against Streptococcus uberis on nutrient agar by 27.7% of the isolates. In conjunction with the antimicrobial investigations, an array of enzymatic assays encompassing amylase, protease, lipase, phosphate solubilization, urease, and cellulase were executed. The outcomes revealed that a substantial portion of the examined actinomycetes exhibited positive reactions in at least half of the conducted assays, with amylase and protease production being particularly prominent, were observed from 94% of the isolates. These findings, drawn from the amassed dataset, underscore the remarkable diversity of antimicrobial and enzymatic activities within the actinomycetes thriving in the mangrove environment. This diversity exemplifies the adaptability of these mangrove-associated actinomycetes, underscoring their capacity to generate a versatile spectrum of secondary metabolites and biochemical responses as a strategy for survival within this unique ecosystem.

Formulation and Evaluation of Antibacterial and Anti-Inflammatory Emulgel Containing Eugenia caryophyllus Buds Extract

ABSTRACT: Background: Eugenia caryophyllus is a valuable aromatic spice used in household cooking. Traditional healers frequently employ the plant, which is said to have therapeutic qualities, in herbal concoctions to treat a variety of illnesses and conditions. Objective: Eugenia caryophyllus clove buds have antibacterial, analgesic, and anti-inflammatory properties. The formulation of clove emulgel and its assessment using a variety of evaluation criteria were the main objectives of the current study. Clove emulgel was evaluated for its anti-inflammatory and anti-microbial properties. Materials and Procedures: We extracted and assessed the oils from Eugenia caryophyllus buds for phytochemical testing using solvents such as methanol, ethanol, petroleum ether, and N-hexane. We prepare emulgel and test it for spreadability, pH, and other organoleptic characteristics. We used egg albumin denaturation as a protein to measure the in vitro anti-inflammatory efficacy. We tested the antibacterial susceptibility using the agar-well diffusion method. Results: Alkaloids, saponins, tannins, steroids, carbohydrates, and glycosides were the phytochemical components found in clove bud extract. Physical factors such as color, consistency, and state—such as semi-solid, smooth, and brownish-gummy—are included in this category of evaluation parameters. The emulgel's pH was 5.35, its spreadability ranged from 1.6 to 2.5 cm, and no phase separation was noticed while the emulgel was stored. An in vitro anti-inflammatory test (spectroscopy method) and an antimicrobial test (zone of inhibition) were used to evaluate the anti-inflammatory activity of emulgel. Comparing clove oil emulgel to a typical medication, these evaluations found that it demonstrates strong anti-inflammatory and antibacterial resistance. Conclusion: In conclusion, Clove Buds Emulgel has demonstrated antibacterial activity against both gram-positive and gram-negative bacterial strains. Emulgel demonstrated the inhibitory response percentage in relation to the standard. This validates the roles that E. caryophyllus has been shown to play in protecting human health. This innovative emulgel mixture was applied to arthritis to lessen microbial infection and joint discomfort. In addition, more preclinical and clinical trials will be needed for this research in order to successfully commercialize the emulgel formulation for the treatment of inflammation and antimicrobial activity.