Potent Antibacterial Activity Research Articles

Alkyl Pyridinol Compounds Exhibit Antimicrobial Effects against Gram-Positive Bacteria

Background/Objectives. The rise of antibiotic-resistant pathogens represents a significant global challenge in infectious disease control, which is amplified by the decline in the discovery of novel antibiotics. Staphylococcus aureus continues to be a highly significant pathogen, causing infections in multiple organs and tissues in both healthcare institutions and community settings. The bacterium has become increasingly resistant to all available antibiotics. Consequently, there is an urgent need for novel small molecules that inhibit the growth or impair the survival of bacterial pathogens. Given their large structural and chemical diversity, as well as often unique mechanisms of action, natural products represent an excellent avenue for the discovery and development of novel antimicrobial treatments. Anaephene A and B are two such naturally occurring compounds with significant antimicrobial activity against Gram-positive bacteria. Here, we report the rapid syntheses and biological characterization of five novel anaephene derivatives, which display low cytotoxicity against mammalian cells but potent antibacterial activity against various S. aureus strains, including methicillin-resistant S. aureus (MRSA) and the multi-drug-resistant community-acquired strain USA300LAC. Methods. A Sonogashira cross-coupling reaction served as the key step for the synthesis of the alkyl pyridinol products. Results/Conclusions. Using the compound JC-01-074, which displays bactericidal activity already at low concentrations (MIC: 16 μg/mL), we provide evidence that alkyl pyridinols target actively growing and biofilm-forming cells and show that these compounds cause disruption and deformation of the staphylococcal membrane, indicating a membrane-associated mechanism of action.

One-step hydrothermal synthesis of F,N,S-doped photoluminescent carbon dots with yellowish-orange emission for sensitive Cu2+ ion detection: Environmental and biomedical applications

Herein, fluorine-, nitrogen-, and sulfur-doped carbon dots (FNS-CDs) were prepared via a one-step hydrothermal synthesis using flufenamic acid and thiourea as precursors, which showed yellowish-orange fluorescence both in aqueous solution and in the solid state. The as-prepared FNS-CDs were monodisperse and had an average diameter of 4 nm, good water solubility, a fluorescence quantum yield of 18.63 %, and excellent pH and ionic strength stability. The optimal excitation/emission wavelengths of the FNS-CDs were 406/570 nm, with an excitation-dependent wavelength range of 365–435 nm. The surface states, morphologies, and elemental compositions of the FNS-CDs were characterized using FTIR, XRD, TEM, and XPS. In addition, the FNS-CDs without any further modification exhibited high selectivity and sensitivity as nanosensors for Cu2+ over other metal ions. The PL quenching phenomenon can be used to detect Cu2+ ions within a linear range of 1–25 μM with a detection limit of 83.10 nM and an association constant of 1.29 × 104 M−1. The PL of the FNS-CDs was significantly quenched by Cu2+ ions through static quenching and was restored upon the subsequent addition of EDTA. The practical application was demonstrated through the detection of Cu2+ ions in real water samples, yielding recovery rates ranging from 97.8 % to 103.9 % with an RSD below 2.5 %. The FNS-CDs/Cu2+ complex exhibits potent antibacterial activity against S. aureus (85.27 %±2.1 %) and E. coli (91.31 %±1.6 %), whereas the FNS-CDs/Cu2+ has a higher inhibitory effect on the growth of E. coli. Furthermore, the FNS-CDs (100 μg/mL) were used for cell imaging, showing low toxicity to HCT-116 cells exhibited yellowish-orange fluorescence under a confocal microscope.

A new tetrahydroxybenzophenone from a marine-associated fungus of penicillium sp. and its potential antibacterial activity

Penicillium species are renowned for their ability to produce a wide range of secondary metabolites with medicinal properties. In this study, compounds 1-10 were isolated from Penicillium sp. Z-16, of which compound 1 is a new benzophenone derivative named methyl 2-(2,6-dihydroxy-4-methylbenzoyl)-4,5-dihydroxy-3-methoxybenzoate. The chemical structure of 1 was determined through comprehensive spectroscopic analysis, including 1D, 2D NMR (HMBC, HSQC) and HRESIMS. In addition, six other known compounds (11-16) were isolated and identified from Penicillium sp. T-5-1. The antimicrobial activity tests demonstrated that compound 1 was moderately active against Candida albicans with a MIC value of 125 μg/mL, while compound 2 showed a MIC value of 62.5 μg/mL against Staphylococcus aureus.

Lentil Extract-Mediated Ag QD Synthesis: Predilection for Albumin Protein Interaction, Antibacterial Activity, and Its Cytotoxicity for Wi-38 and PC-3 Cell Lines.

Recent focus has been directed toward semiconductor nanocrystals owing to their unique physicochemical properties. Nevertheless, the synthesis and characterization of quantum dots (QDs) pose considerable challenges, limiting our understanding of their interactions within a biological environment. This research offers valuable insights into the environmentally friendly production of silver quantum dots (Ag QDs) using lentil extract and clarifies their distinct physicochemical characteristics, previously unexplored to our knowledge. These findings pave the path for potential practical applications. The investigation of the phytochemical-assisted Ag QDs' affinity for BSA demonstrated modest interactions, as shown by the enthalpy and entropy changes as well as the associated Gibbs free energy during their association. Steady-state and time-resolved fluorescence spectroscopy further demonstrated a transient effect involving dynamic quenching, predominantly driven by Forster resonance energy transfer. Additionally, the study highlights the potential broad-spectrum antibacterial activity of Ag QDs (<5 nm, a zeta potential of -3.04 mV), exhibiting a remarkable MIC value of 1 μg/mL against Gram-negative bacteria (E. coli) and 1.65 μg/mL against Gram-positive bacteria (S. aureus). They can readily enter cells and tissues due to their minuscule size and the right chemical environment. They cause intracellular pathway disruption, which leads to cell death. This outcome emphasizes the distinctive biocompatibility of the green-synthesized Ag QDs, which has been confirmed by their MTT assay-based cytotoxicity against the PC-3 and Wi-38 cell lines.

Synthesis and evaluation of novel sulfamethoxazole-containing 1,8-dioxo-decahydroacridine derivatives: Antimicrobial activity and emission properties

A straightforward and efficient method for synthesizing 1,8-dioxo-decahydroacridine derivatives is presented, utilizing a one-pot, three-component condensation reaction involving dimedone, sulfamethoxazole, and aromatic aldehydes. The primary objective of this synthesis is to incorporate the sulfamethoxazole ring into the acridine family structure and examine the antibacterial effects and fluorescence properties of the compounds. The antibacterial activity of the synthesized compounds was evaluated against various gram-positive and gram-negative microorganisms, as well as a fungal strain, using the disk diffusion method, minimum inhibitory concentration determination, and bactericidal assays. Notably, five compounds exhibited potent antibacterial activity against both strains of Bacillus cereus. Furthermore, the influence of pH on the fluorescence emission intensity and absorption spectrum of the synthesized compounds was investigated, revealing that all products displayed fluorescence radiation.

The Potential Alternative Antibacterial Activity of Falcata (Falcataria Falcata) Leaf Methanolic Extract against Staphylococcus Aureus and Escherichia Coli

The Potential Alternative Antibacterial Activity Of Falcata (Falcataria falcata) Leaf Methanolic Extract Against Staphylococcus aureus And Escherichia coli  Laliefe B. Arnan; Katherine Joy S. Escueta; Nor Rashida P. Rashid; Elyca M. Tacbobo; Queenie Rose M. Tinoy  Degree: Bachelor of Science in Pharmacy  Thesis Adviser: Junnin Gay L. Garay, RPh, CPh, MS Pharm Falcata is a plant that can be found in the Philippines and is used for the production of wood veneer and plywood. While in Indonesia, it is used as traditional remedy for malaria (Budiarti et al. 2020). They belong to the Fabaceae family, a family known for having great antibacterial effects (Gamo et al. 2015). This study used a percolation extraction method and the percentage yield is calculated to determine the yield from the falcata extract. Disc diffusion method is used for susceptibility testing and determining the zone of inhibition for the different groups. The CLSI guidelines for Staphylococcus aureus and Escherichia coli will be used to determine the antibacterial effect of the extract, in terms of resistance, intermediate, and susceptible results. From the results, the percentage yield of the methanolic crude leaf extract of Falcataria falcata is 2.67%. Leaves from the Falcataria falcata plant were extracted and tested against bacteria. The extracts showed promise in inhibiting the growth of Staphylococcus aureus and Escherichia coli bacteria, with 75% concentration as being more effective. However, these bacteria showed some resistance to all extract concentrations: S. aureus (90% - resistant, 75% - intermediate, 50% - resistant, 25% - resistant); E. coli (90% - resistant, 75% - resistant, 50% - resistant, 25% - resistant). Further study is needed to determine the exact antibacterial properties of the plant.

Exploring Acyl Thiotriazinoindole Based Pharmacophores: Design, Synthesis, and SAR Studies with Molecular Docking and Biological Activity Profiling against Urease, α-amylase, α-glucosidase, Antimicrobial, and Antioxidant Targets.

A diminutive chemical library of acyl thiotriazinoindole (ATTI) based bioactive scaffolds was synthesized, instigated by taking the economical starting material Isatin, through a series of five steps. Isatin was first nitrated followed by the attachment of pentyl moiety via nucleophilic substitution reaction. The obtained compound was reacted with thiosemicarbazide to obtain thiosemicarbazone derivative, which was eventually cyclized using basic conditions in water as solvent. Finally, the reported series was obtained through reaction of nitrated thiotriazinoindole moiety with differently substituted phenacyl bromides. The synthesized compounds were characterized using NMR spectroscopy and elemental analysis. Finally, the synthesized motifs were scrutinized for their potential to impede urease, α-glucosidase, DPPH, and α-amylase. Compound 5h with para cyano group manifested the most pivotal biological activity among all, displaying IC50 values of 29.7 ± 0.8, 20.5 ± 0.5 and 36.8 ± 3.9µM against urease, α-glucosidase, and DPPH assay, respectively. Simultaneously, for α-amylase compound 5g possessing a p-CH3 at phenyl ring unfolded as most active, with calculated IC50 values 90.3 ± 1.1µM. The scaffolds were additionally gauged for their antifungal and antibacterial activity. Among the tested strains, 5d having bromo as substituent exhibited the most potent antibacterial activity, while it also demonstrated the highest potency against Aspergillus fumigatus. Other derivatives 5b, 5e, 5i, and 5j also exhibited dual inhibition against both antibacterial and antifungal strains. The interaction pattern of derivatives clearly displayed their SAR, and their docking scores were correlated with their IC50 values. In molecular docking studies, the importance of interactions like hydrogen bonding was further asserted. The electronic factors of various substituents engendered variety of interactions between the ligands and targets implying their importance in the structures of the synthesized heterocyclic scaffolds. To conclude, the synthesized compounds had satisfactory biological activity against various important targets. Further studies are therefore encouraged by attachment of different substitutions in the structure at various positions to enhance the activity of these compounds.

Engineering fully quaternized (Dimethylamino)ethyl methacrylate-based photoresins for 3D printing of biodegradable antimicrobial polymers

Nowadays, medical devices or implants are widely used in the medical field to treat different diseases. However, bacterial infections are one of the significant problems associated with medical devices and are recognized as a concern in healthcare worldwide. Addressing this problem has driven the exploration of new materials with potent antibacterial properties. In this regard, quaternary ammonium compounds (QACs), which are organic salts with an alkane chain and a charged part of quaternary ammonium groups, came up with a potent antibacterial activity. Herein, we report for the first-time dimethylamino ethyl methacrylate (DMAEM) derived quaternary ammonium monomer and crosslinker to prepare photoresins for DLP (Digital light processing) 3D printing. The structure of the synthesized monomer and crosslinker was confirmed via FTIR (Fourrier Transform Infrared) and 1H NMR (Hydrogen Nuclear Magnetic Resonance) while the physicochemical properties of the 3D printed polymer were investigated using TGA (Thermogravimetric Analysis), DSC (Differential Scanning Calorimeter) and UTM (Universal testing machine). By optimizing the printing conditions and monomer to crosslinker ratio, we can print high-resolution 3D-printed objects. Additionally, in vitro biodegradation, cytocompatibility, and hemocompatibility tests revealed that the printed polymers are biodegradable, cytocompatible, and hemocompatible in nature. More importantly, the printed polymers exhibited strong antibacterial activity against both gram-negative and gram-positive bacteria, suggesting their potential utility in personalized antibacterial medical devices.

Structural, morphological, optical, and antimicrobial study of Mikania micrantha (leaf) extract treated zinc doped cobalt ferrite nanoparticles and antibacterial clothing applications

To manage pathogenic diseases, different applications of nanotechnology have been harnessed to improve the antimicrobial and self-cleaning attributes of materials. The objective of this study is to examine the anti-microbial activity of silk thread; coated (ultra-sonication method) with Zn doped cobalt ferrite nanoparticles with future prospects of developing interlayer of surgical facemask or producing antibacterial wearing. The nanoparticles were synthesized following the co-precipitation method by using Mikania micrantha leaf extract. The potential antibacterial activity (against E. coli and S. aureus) of the thread as well as the nanoparticles was recorded using the Zone of Inhibition (ZOI) test result. XRD results showed the cubic crystal structure and the lattice parameter change due to Zn doping. SEM findings revealed particle agglomeration, though the particles retained an approximately spherical shape of around 52.498 nm for undoped and 32.13 nm for doped materials. FT-IR analysis confirmed that flavonoids from the leaf extract stabilized the nanoparticles. This research investigated the antibacterial capabilities of threads coated with nanoparticles; using the agar well diffusion method, the study established the robust antibacterial capabilities of the nanoparticles-coated thread. Notably, the CoFe2O4 NPs exhibited strong antimicrobial activity against specific bacterial strains, and Zn doping enhances this characteristic.

Probiotic Lactobacillus salivarius mediated synthesis of silver nanoparticles (AgNPs-LS): A sustainable approach and multifaceted biomedical application

Biogenic synthesis of silver nanoparticles (AgNPs) has emerged as an eco-friendly and sustainable approach with diverse biological applications. This study presents synthesis of AgNPs-LS using a probiotic strain Lactobacillus salivarius (L. salivarius) and explores their multifaceted biological activities, including antibacterial, antibiofilm, anti-quorum sensing, antifungal, antioxidant, anticancer, anticoagulant and thrombolytic properties. The biosynthesis of AgNPs-LS was successfully achieved using L. salivarius cell free supernatants, resulting in well-characterized nanoparticles as confirmed by UV–Vis spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, transmission electron microscopy (TEM) and dynamic light scattering (DLS) and zeta potential analysis. The AgNPs-LS demonstrated potent antibacterial activity against different pathogenic bacteria (C. violaceum, P. aeruginosa, S. aureus, E. coli and S. marcescens), emphasizing their potential in combating bacterial infections. Moreover, these AgNPs-LS were effective in inhibiting biofilm formation (>60 % at 1/2 MIC), a key mechanism of bacterial virulence, highlighting their utility in preventing biofilm-related infections. AgNPs-LS exhibited anti-quorum sensing activity, disrupting bacterial communication systems and potentially reducing virulence factor such as, violacein production in C. violaceum, pyocyanin production in P. aeruginosa and prodigiosin production in S. marcescens. Additionally, AgNPs-LS also exhibited notable antifungal activity towards a different pathogenic fungus (F. proliferatum, P. purpurogenum, A. niger and R. stolonifer). In terms of health applications, the AgNPs-LS displayed significant antioxidant activity, effectively scavenging DPPH• (IC50 = 42.65 μg/mL) and ABTS•+ (IC50 = 53.77 μg/mL) free radicals. Furthermore, AgNPs-LS showed cytotoxicity against breast cancer cells (MCF-7) (IC50 = 52.29 μg/mL), positioning them as promising candidates for cancer therapy. Moreover, AgNPs-LS were also shown promising anticoagulant and thrombolytic activities under practical conditions. Therefore, the biogenic synthesis of AgNPs-LS using L. salivarius offers a sustainable and cost-effective route for producing AgNPs with an array of biological activities. These AgNPs-LS have the potential to address various challenges in healthcare, ranging from antimicrobial, anticancer applications to biofilm inhibition, antioxidant therapy, anticoagulant and thrombolytic agents.

Bioassay-guided fractionation and in vitro and in silico biological activities of 2,4-di-tert-butylphenol isolated from Nocardiopsis sp. strain LC-8

In this study, an actinomycete strain was isolated from freshwater soil sediments to produce bioactive metabolite with a broad array of biological activities. Initially, preliminary antibacterial screening of isolate was performed by perpendicular streak method which showed the growth inhibition of all tested bacterial pathogens. Based on the culture characteristics, morphological identification, and 16S rRNA gene sequencing, the isolate was identified as Nocardiopsis sp. strain LC-8. Ethyl acetate extract of strain LC-8 showed potential antibacterial activity against tested bacterial pathogens with a maximum zone of inhibition of 16.98±0.57 mm against Staphylococcus aureus. After column chromatography, fraction 2 (F2) of the extract exhibited prominent growth inhibition activity against all tested bacterial and fungal pathogens. Antioxidant activity of F2 showed potent free radical scavenging activity with low IC50 values (DPPH - 278.15±0.35 μg/ml, ABTS - 367.55±1.13 μg/ml, and FRAP - 347.48±1.35 μg/ml). Total phenolic content of F2 was quantified as 362.44±1.25 mg gallic acid equivalent/gram extract. As per spectral analyses, the isolated compound from F2 was identified as 2,4-di-tert-butylphenol which further induced cytotoxic (IC50 value - 17.5±1.5 μg/ml) and apoptosis activity against MCF-7 cells. Molecular interaction studies of 2,4-di-tert-butylphenol with target proteins of pathogens and cancer cells displayed good docking score values. Finally, molecular dynamics simulation was performed to determine the stable structure of the protein-ligand system and effectiveness of 2,4-di-tert-butylphenol against the target protein. In conclusion, Nocardiopsis sp. strain LC-8 may act as a promising source for the production of 2,4-di-tert-butylphenol aiding diverse therapeutic roles.

Isolation and Characterization of Bacteriocin Producing Levilactobacillus brevis Strain ABRIINW-K from Buffalo Dung

Bacteriocins are proteins secreted by many species of bacteria to inhibit other bacteria, thus eliminating competitors to gain resources. Bacteria from the Lactobacillus group are known for their applications as probiotics and food preservatives. They have earned a reputation for producing substances that inhibit the growth of other microorganisms, which include organic acids, diacetyl, and bacteriocins. Produced by the ribosomes, bacteriocins are cationic proteins that inhibit other bacteria coexisting within a shared ecological habitat. Due to their potential uses in a variety of applications large-scale production of Bacteriocins would be necessary. The study aimed to identify and characterize Lactobacillus bacteria that produce potent bacteriocins and to analyze the antimicrobial activity and stability of the isolated bacteriocin under various physical and biochemical conditions. A total of 50 samples including buffalo dung, cheese, and rhizospheric region of plants were screened to isolate 8 Lactobacillus Li-1, Li-2, Li-3, Li-4, Li-5, Li-6, Li-7, and Li-8, confirmed by gram staining and other biochemical tests. The cell free supernatant from the Li-3 strain showed higher inhibition of Escherichia coli and Staphylococcus aureus, as compared to the other isolated strains. Li-3 strain was further identified as Levilactobacillus brevis strain ABRIINW-K by 16S rRNA gene sequencing. The bacteriocin isolated from this strain is a thermostable peptide (~6kDa), which is characteristic of class II bacteriocins, with potent antibacterial activity against Lactobacillus rhamnosus, Escherichia coli, and Salmonella enterica.

Optimization of synthesis and characterization of novel sodium alginate/montmorillonite/zinc oxide bionanocomposite as an antibacterial agent against Streptococcus mutans

Due to the escalating bacterial resistance, the objective of the current investigation was to discover the most favorable condition for the fabrication of a novel bionanocomposite consisting of sodium alginate, montmorillonite, and ZnO, possessing the greatest degree of antibacterial efficacy. To determine the optimal synthesis conditions for nanocomposite with the most favorable antimicrobial activity, a total of nine experiments were devised via the Taguchi methodology. The studied nanocomposites were produced using the in situ method. The antibacterial efficacy of the synthesized nanocomposites was assessed against Streptococcus mutans through the utilization of the colony-forming unit methodology. The nanocomposites synthesized, consisting of 60 mg/mL alginate, 0.6 mg/mL montmorillonite, and 6 mg/mL ZnO, exhibited the most potent antibacterial activity. The greatest effect on bacterial viability was related to the ZnO factor. The synthesis of alginate/MMT/ZnO nanocomposites with desirable conditions was confirmed using various analyses. This study showed that alginate/MMT/ZnO nanocomposite has high performance under optimal conditions, and applying optimal levels of components improves the antibacterial properties of the synthesized nanocomposite.

Phytochemical Screening and Biological Activity (Antioxidant and Antibacterial) of Punica granatum Fruit peel extract Cultivated in Sa'dah Governorate-Yemen

Punica granatum (Pomegranate) is a valuable source of secondary plant metabolism compounds (SMs) that are widely used in the pharmaceutical, cosmetics, and food industries. The phytochemical screening illustrates that the Sa’dah P. granatum cultivar peel ethanol extract containsvarious beneficial components, including Flavonoids, Alkaloids, Steroids, Phenols, and Tannins. Moreover, the Sa’dah P. granatum cultivar peel ethanol extract (1.3 μg/ml) exhibited significant antioxidant activity compared to low concentrations of ascorbic acid (0.4, 0.6, 0.8, and 1 μg/ml). Furthermore, the Sa’dah P. granatum cultivar peel ethanol extract displays potent antibacterial activities against selected pathogenic bacteria (Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa) compared to two nominated antibiotics (Ampicillin and Gentamicin). This remarkable performance can be attributed to the presence of phenols and flavonoid compounds, which exhibit high antioxidant activity.

Understanding the biosynthesis, metabolic regulation, and anti-phytopathogen activity of 3,7-dihydroxytropolone in Pseudomonas spp.

The genus Pseudomonas is a prolific source of specialized metabolites with significant biological activities, including siderophores, antibiotics, and plant hormones. These molecules play pivotal roles in environmental interactions, influencing pathogenicity, inhibiting microorganisms, responding to nutrient limitation and abiotic challenges, and regulating plant growth. These properties mean that pseudomonads are suitable candidates as biological control agents against plant pathogens. Multiple transposon-based screens have identified a Pseudomonas biosynthetic gene cluster (BGC) associated with potent antibacterial and antifungal activities, which produces 7-hydroxytropolone (7-HT). In this study, we show that this BGC also makes 3,7-dihydroxytropolone (3,7-dHT), which has strong antimicrobial activity toward Streptomyces scabies, a potato pathogen. Through metabolomics and reporter assays, we unveil the involvement of cluster-situated genes in generating phenylacetyl-coenzyme A, a key precursor for tropolone biosynthesis via the phenylacetic acid catabolon. The clustering of these phenylacetic acid genes within tropolone BGCs is unusual in other Gram-negative bacteria. Our findings support the interception of phenylacetic acid catabolism via an enoyl-CoA dehydratase encoded in the BGC, as well as highlighting an essential role for a conserved thioesterase in biosynthesis. Biochemical assays were used to show that this thioesterase functions after a dehydrogenation-epoxidation step catalyzed by a flavoprotein. We use this information to identify diverse uncharacterized BGCs that encode proteins with homology to flavoproteins and thioesterases involved in tropolone biosynthesis. This study provides insights into tropolone biosynthesis in Pseudomonas, laying the foundation for further investigations into the ecological role of tropolone production.IMPORTANCEPseudomonas bacteria produce various potent chemicals that influence interactions in nature, such as metal-binding molecules, antibiotics, or plant hormones. This ability to synthesize bioactive molecules means that Pseudomonas bacteria may be useful as biological control agents to protect plants from agricultural pathogens, as well as a source of antibiotic candidates. We have identified a plant-associated Pseudomonas strain that can produce 3,7-dihydroxytropolone, which has broad biological activity and can inhibit the growth of Streptomyces scabies, a bacterium that causes potato scab. Following the identification of this molecule, we used a combination of genetic, chemical, and biochemical experiments to identify key steps in the production of tropolones in Pseudomonas species. Understanding this biosynthetic process led to the discovery of an array of diverse pathways that we predict will produce new tropolone-like molecules. This work should also help us shed light on the natural function of antibiotics in nature.

Phytochemical Analysis and Antimicrobial Potential of Parthenium hysterophorous and Lantana camara.

Parthenium hysterophorous and Lantana camara are notable for their significant phytochemical and antimicrobial properties. Advancements in phytochemical research have led to the development of novel formulations and products derived from P. hysterophorus and L. camara. For instance, patent extracts from these plants have been utilized in the formulation of pharmaceutical drugs, herbal supplements, cosmeceuticals, and agricultural products. P. hysterophorous, commonly known as Santa Maria feverfew or Congress grass, contains various bioactive compounds like terpenoids, flavonoids, phenolics, and alkaloids.These compounds are the key to its medicinal properties, particularly its antimicrobial activity. On the other hand, L. camara, often referred to as wild sage, is rich in phytochemicals such as terpenoids, flavonoids, and alkaloid glycosides. P. hysterophorous and L. camara plants selected and checking their antimicrobial activity by agar well diffusion method. In our study, we found that the leaf extract of P. hysterophorous exhibited the most potent antibacterial activity against E. coli. P. hysterophorous exhibited the most potent antifungal activity against A. niger and T. viride, with a diameter of inhibition zone measuring 12 mm, followed by A. flavus and A. parasiticus. In case of L. camara, the inhibitory zone ranging from 14 to 18 mm was detected against S. abony, P. aeruginosa, E. coli, and K. pneumonia. The leaf extract of the maximum zone of inhibition in case of L. camara was shown by A. flavus (12mm). The present study suggests that these two weeds could be useful in the development of bactericides and fungicides.

Structural Connectivity and Bioactivity in Sol-gel Silicate Glass Design

Bioactive glasses (BGs) bond with bone by forming hydroxy carbonate apatite (HCA) upon reaction in physiological fluid, a phenomenon known as bioactivity. BGs structural network connectivity determines their bioactivity. Sol-gel BGs are synthesized through the hydrolysis and condensation of metal alkoxide precursors in the presence of a catalyst, in aqueous environments. Several sol-gel synthesis parameters directly impact BG network connectivity: pH (i.e. acid or basic catalysis), water to alkoxide ratio (Rw), alkoxide type and presence of dopant ions. However, the relationship between bioactivity and these parameters remains surprisingly unexplored.This study highlights the relationship between synthesis pH, Rw, network connectivity and bioactivity in silica-based sol-gel BGs and BGs doped with titanium (Ti) ions (TiBGs), the latter selected for their known ability to enhance network connectivity. BGs and TiBGs are synthesized with various Rw values under acidic and basic conditions, and their bioactivity is assessed in simulated body fluid for 7 days.Increasing Rw decreases network connectivity and increases bioactivity of BGs with high network connectivity, as observed for base-catalyzed BGs and for both acid and base catalyzed TiBGs, but not in BGs with lower connectivity as evidenced in acid-catalyzed BGs. Basic catalysis of TiBGs prevents crystalline TiO2 domain formation, which was instead consistently observed in TiBGs synthesized under acidic catalysis.These findings help the design of BGs for applications where ion release needs to be enhanced even in the presence of dopants that slow down HCA formation, and of BGs with specific properties, e.g. TiO2-containing BGs with potential bactericidal activity. Statement of SignificanceBioactive glasses (BGs) bond with bone by dissolving and forming hydroxycarbonate apatite (HCA) on their surface, offering applications in medicine and dentistry. BG's network connectivity influences its dissolution rate, and hence HCA formation. While solution-gelation (sol-gel) is commonly used for BG production, the effect of sol gel synthesis parameters on HCA formation remains unexplored. We studied the relationship between synthesis parameters (water-to-alkoxide ratio (Rw), catalyst, and dopant ions, particularly titanium), BG network connectivity, and HCA formation. We find that increasing Rw with any catalyst enhances HCA formation, particularly in glasses with high network connectivity. This understanding allows tailoring BG synthesis for different applications, e.g. those requiring doping with ions that increase network connectivity and fills a crucial gap in BG literature.

Cymbopogon distans: A source of essential oil with potential antibacterial, antifungal, and mosquito-repelling properties

The essential oils have become increasingly popular in recent years due to their potential as natural antimicrobial agents and a means of controlling mosquitoes. This study explored the chemical composition and antibacterial, antifungal, and mosquito-repellent properties of Cymbopogon distans (Nees ex Steud.) Wats (Poaceae) is a less explored aromatic plant distributed in the Himalayas. The fresh biomasses of C. distans and two commercially grown Cymbopogon species, namely C. flexuous and C. martini were submitted to hydrodistillation to extract their essential oils. Gas chromatography-flame ionisation detector (GC-FID) and gas chromatography-mass spectrometry (GC-MS) analyses revealed the presence of citral, geraniol, and geranyl acetate as major constituents of C. distans. The essential oils of C. flexuous and C. martini were dominated by citral and geraniol, respectively. Antibacterial and antifungal activities of C. distans essential oil were evaluated using disc diffusion and micro-dilution methods and compared with the essential oils of C. flexuous and C. martini. C. distans essential oil showed a broader spectrum of potent antibacterial and antifungal activities (minimum inhibitory concentration: 0.41 mg/ml and minimum bactericidal concentration/minimum fungicidal concentration: 0.82 mg/ml) against the test strains. C. distans essential oil, in combination with norfloxacin and penicillin G showed synergistic interactions (fractional inhibitory concentration ≤0.5) against Staphylococcus aureus and Staphylococcus epidermidis. C. distans essential oil showed a repellent effect against Aedes aegypti (73.3 %) that was comparable to C. winterianus essential oil (75.6 %). This study suggests that C. distans essential oil may be a promising natural candidate for developing new herbal therapies for combating microbial infections and mosquito-borne diseases.

Design, synthesis, characterization and biological screening of novel thiosemicarbazones and their derivatives with potent antibacterial and antidiabetic activities

Thiosemicarbazones and their derivatives were synthesized by reacting carbonyl compounds with thiosemicarbazide, followed by treatment with metal salts. The prepared thisemicarbazones such as (2E)-2-[(1,5,7-trichloronaphthalen-2-yl)-methylidene]-hydrazine-1-carbothioamide,(2E)-2-[(1,5,7-trihydroxynaphthalen-2-yl)-methylidene]hydrazine-1-carbothioamide and these were characterized by using diverse spectral techniques, such as UV–Vis and FT-IR. The synthesized compounds were subsequently evaluated for their antibacterial properties against Gram(+) Bacillus subtilis and Gram(-) Escherichia coli, using ciprofloxacin as a reference, as well as for their anti-microbial activities. For the evaluation of anti-diabetic activity, Acarbose served as the reference. Molecular docking results indicated that WS-1 and WS-2 exhibited superior performance against Alpha-glucosidase proteins, evidenced by their lowest binding energies (−8.1 and −8.3 kcal/mol) respectively compared to other ligands. These findings suggest that WS-1 and WS-2 are promising candidates for further research and development by pharmaceutical companies to explore additional biological activities.

Pyridazinone-based derivatives as anticancer agents endowed with anti-microbial activity: molecular design, synthesis, and biological investigation.

Cancer patients undergoing chemotherapy are highly susceptible to infections owing to their compromised immune system, which also promotes cancer progression through inflammation. Thus, this study aimed to develop novel chemotherapeutic agents with both anticancer and antimicrobial properties. A series of diarylurea derivatives based on pyridazinone scaffolds were designed, synthesized, and characterized as surrogates for sorafenib. The synthesized compounds were tested for their antimicrobial activity and screened against 60 cancer cell lines at the National Cancer Institute (NCI). Compound 10h exhibited potent antibacterial activity against Staphylococcus aureus (MIC = 16 μg mL-1), whereas compound 8g showed significant antifungal activity against Candida albicans (MIC = 16 μg mL-1). Additionally, ten compounds were further evaluated for VEGFR-2 inhibition, with compound 17a showing the best inhibitory activity. Compounds 8f, 10l, and 17a demonstrated significant anticancer activity against melanoma, NSCLC, prostate cancer, and colon cancer, with growth inhibition percentages (GI%) ranging from 62.21% to 100.14%. Compounds 10l and 17a were selected for five-dose screening, displaying GI50 values of 1.66-100 μM. Compound 10l induced G0-G1 phase cell cycle arrest in the A549/ATCC cell line, increasing the cell population from 85.41% to 90.86%. Gene expression analysis showed that compound 10l upregulated pro-apoptotic genes p53 and Bax and downregulated the anti-apoptotic gene Bcl-2. Molecular docking studies provided insights into the binding modes of the compounds to the VEGFR-2 enzyme. In conclusion, the pyridazinone-based diarylurea derivatives developed in this study show promise as dual-function antimicrobial and anticancer agents, warranting further investigation.