A Comprehensive Study on Enhancing Microbicidal Activity of Pure and Ion-Exchanged Zeolites Through Structural and Chemical Determinants

In this study Aloe vera accessions were collected from 12 states covering different climatic zones of India. The aqueous crude extracts were investigated for qualitative phytochemical diversity analysis, quantitative estimation of total phenol, alkaloid and flavonoid content and their antibacterial potential against ATCC (American Type Culture Collection) bacterial reference strains. Pearsoncoefficient correlation was used to correlate the quantitative estimation between tested bio-active compounds. Antibacterial potential was evaluated by agar well diffusion method against 9 bacterial reference ATCC strains. MIC (Minimum Inhibitory Concentration) values were calculated by microbroth dilution method. Different Aloe vera accessions showed the presence of alkaloids, glycosides, reducing sugar, phenolic compounds, flavonoids and tannins. Significant correlation was observed between alkaloids and phenols, and flavonoids and alkaloid contents. The correlation analysis also revealed the significant negative correlation between temperature and phenol (-0.803), and temperature and alkaloids (-0.779). Antibacterial activities measured in term of zone of inhibition against tested bacterial strains varied in different accessions of Aloe vera. Aqueous leaf extract of Aloe vera showed good antibacterial potential against both type of bacterial strains, gram positive S. aureus as well as gram negative E. coli and S. typhi. Highland and semi-arid zone accessions showed maximum phytochemical and antibacterial potential as compared to other Aloe vera accessions. Minimum MIC value of 1.2 mg/ml was shown by Highland samples against most of the reference strains. The results also concluded that phytochemical composition of Aloe vera is influenced by various environmental factors especially temperature and it is further correlated with antimicrobial potential of the plant.

Introduction: Prolonged use of antibiotics and antifungals for treating oral infections may develop resistance as a consequence of which medicinal plants having antimicrobial properties are being used to explore natural alternatives that are almost equally effective along with being cost-effective to cater to patients having financial constraints. Objective: The objective of this paper was to examine the presence of anti-bacterial and anti-fungal potential of the extract drawn from cassia fistula leaves. Ethanolic extract of cassia fistula leaves was evaluated for antimicrobial potential against bacterial and fungal strains responsible for causing denture-related stomatitis (DRS). Materials & Methods: In this cross-sectional study, cassia fistula leaf extract was obtained using the Soxhlet apparatus. Anti-bacterial potential was examined utilizing the agar well diffusion method whereas anti-fungal ability was observed using the tube dilution method which aided in evaluating the Minimal Inhibitory Concentration (MIC) for the extract. The anti-bacterial and anti-fungal potential of cassia fistula leaf extract was tested contrary to staphylococcus aureus and candida albicans. The zone of inhibition (ZOI) of the extract for anti-bacterial activity was compared with 5µg/ml ampicillin while the MIC of the extract (4mg, 8mg, 16mg, 32mg, 64mg, 128mg) for anti-fungal potential was evaluated contrary to candida albicans. Results: The outcomes exhibited the anti-bacterial potential of the extract against staphylococcus aureus which was confirmed by giving the ZOI to be 22mm whereas the anti-fungal potential of the extract in contrast to candida albicans was confirmed with the MIC to be 8mg/ml. Conclusions: The research inferences from the analysis indicate that the ethanolic extract obtained from cassia fistula leaves shows potent antifungal and antibacterial properties. As a result, this plant holds the capacity as a natural medicinal resource for addressing diverse oral infections.

Background/Objectives: Antimicrobial resistance represents a critical global health challenge that has been exacerbated by the significant decline in antibiotic development. Natural product-based drugs, particularly plant-derived phenolic compounds, offer promising alternatives to conventional antibiotics. This study aimed to isolate and characterize a novel phenolic compound from Bacopa procumbens, a Mexican perennial repent plant that is widespread in the Mexican valley and produces a variety of saponins, gastrodin derivatives, and phenolic acids, and to evaluate its antibacterial potential against clinically relevant pathogens. Methods: The hydroalcoholic extraction of B. procumbens was followed by liquid-liquid partitioning with ethyl acetate. The resulting fraction underwent chromatographic separation and purification. The structural elucidation of the isolated compound was performed using thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), mass spectrometry (MS-EI), and nuclear magnetic resonance (NMR) techniques. Antimicrobial activity was assessed via a microdilution assay against five bacterial strains, including drug-resistant Staphylococcus species and Gram-negative pathogens. Results: A novel phenolic compound, 5-(p-hydroxybenzoyl) shikimic acid (5pHSA), was isolated and characterized. The compound demonstrated moderate antibacterial activity against methicillin-resistant Staphylococcus haemolyticus and Escherichia coli (minimum inhibitory concentration (MIC) = 100 μg/mL) but showed limited efficacy against Staphylococcus aureus, MRSA, and Klebsiella pneumoniae (MIC > 100 μg/mL). Comparative analysis with the previously isolated compound ProcumGastrodin A revealed structure-activity relationships where the higher lipophilicity of PG-A was correlated with enhanced antimicrobial activity. Conclusions: This study establishes 5pHSA as a novel phenolic compound with moderate antibacterial properties. The findings highlight the importance of molecular polarity and structural complexity in determining antimicrobial efficacy, offering valuable insights into the development of phenolic, acid-based antimicrobial agents to address the growing challenge of antimicrobial resistance.

Himatanthus drasticus (Mart.) Plumel, popularly known as janaguba, is a latex medicinal plant widely used in the region of Cariri (CE) and used as an alternative source for the treatment of numerous diseases. The objective of the present work was to test the antibacterial and modulatory potential of the latex in natura (LIHD) and ethyl acetate extract of H. drasticus latex (EAEHD) alone and in combination with aminoglycoside antibiotics (amikacin and gentamicin) against standard and multiresistant strains, following the method of microdilution in Brain Heart Infusion (BHI) broth. In the evaluation of the minimum inhibitory concentration (MIC) results were obtained ≥ 1024 μg / mL against the standard strains of Escherichia coli , Staphylococcus aureus , Pseudomonas aeruginosa and Klebsiella pneumoniae for both LIHD and EAEHD. The natural products presented synergism in the activity of the aminoglycosides to strains of multiresistant bacteria Escherichia coli (EC 27), Staphylococcus aureus (SA 358) and Klebsiella pneumoniae (KP 10031), however they presented antagonism to Pseudomonas aeruginosa (PA 03). In the quantification of phenols, LIHD had 62.6 mg / g and EAEHD 51.8 mg / g gallic acid / g extract, and for total flavonoids, LIHD had 16.5 and EAEHD had 13.4 mg / g of flavonoids. Further research is needed for a possible use of these natural products combined with antimicrobials tested (aminoglycosides) against pathogenic strains. Through the results it was concluded that the natural products represent promising sources in the fight against bacterial resistance. Keywords: Aminoglycosides; Antimicrobian activity; Inhibitory Minimum Concentration; Himatanthus drasticus .

Antibiotic-resistant bacteria are a serious global health threat, making infections harder to treat and increasing medical costs and mortality rates. To combat resistant bacterial strains, a series of compounds (QS1-12) were synthesized with an excellent yield of 85-92%. Initial assessments of these analogues as potential antibacterial agents were conducted through a preliminary screening against a panel of diverse bacterial strains. The results identified compound QS-3 as the most effective antibacterial candidate, exhibiting exceptional inhibitory activity against P. aeruginosa with a minimum inhibitory concentration (MIC) of 64 μg mL-1. Furthermore, QS-3 demonstrated a favorable synergistic effect when combined with ciprofloxacin. Notably, the compound displayed minimal cytotoxicity, inducing less than 5% lysis of red blood cells (RBCs). Significantly, QS-3 exhibited enhanced inhibitory activity, particularly against the antibiotic-resistant strains AA202 and AA290. In silico predictions of physicochemical properties underscored the drug-like qualities of the designed compounds. Additionally, molecular docking poses, ligPlot images, and a binding affinity of -8.0 kcal mol-1 further reinforced their potential as promising antibacterial agents. Briefly, the reported compound QS3 may be a future broad-range antibacterial agent.

ABSTRACTThe Leccino olive cultivar was grown in pots contained calcareous rendzina soil amended with NPK fertilizer (control treatment) or with further addition of Zeolite A (ZA) containing either zinc (Zn2+) or manganese (Mn2+) (Zn-ZA and Mn-ZA). After one year, vegetative growth and root morphological parameters were measured and elemental analysis was performed on the root, stem, and leaves. Compared to other treatments, the Zn-ZA fertilizer enhanced Zn concentration and total quantity in the root, stem, and leaves, as well as the root diameter. The root volume was greater using Zn-ZA treatment than control treatment. The total quantity of Mn in root and the root length were enhanced when using Mn-ZA compared to control or Zn-ZA treatment. According to the results of this study, it appears that zeolites containing Zn provide favorable conditions for Zn uptake in calcareous soils, while both Zn and Mn zeolites have a positive impact on olive root morphology.

Designing of click-derived 1,2,3-triazoles as potential anti-bacterial agents and sensor towards Al(III) ion in aqueous medium

重金属胁迫对<i>Pseudomonas alcaligenes</i>LH7抗生素抗性的影响

The emergence of antimicrobial resistance necessitates the development of novel antibacterial agents. This study focuses on the synthesis, characterization, and antibacterial evaluation of a series of N3, N5-di(substituted)isoxazole-3,5-diamine derivatives (178a-f) as potential antibacterial agents. The compounds were synthesized using a two-step process involving the formation of N1, N3-di(substituted)malonamide intermediates followed by cyclization with hydroxylamine hydrochloride under microwave irradiation. All synthesized compounds were thoroughly characterized using spectroscopic techniques including IR, 1H-NMR, and mass spectrometry to confirm their structural integrity. The antibacterial activity of the synthesized compounds was evaluated using the Mueller Hinton broth turbidometric method against both Gram-negative (Escherichia coli MTCC 443) and Gram-positive (Staphylococcus aureus MTCC 96) bacterial strains. The minimum inhibitory concentration (MIC) was determined for each compound and compared with the standard drug cloxacillin. Among the synthesized derivatives, compounds 178d, 178e, and 178f exhibited the most potent antibacterial activity. Against E. coli, these compounds showed MIC values of 117 μg/mL, 110 μg/mL, and 95 μg/mL, respectively, surpassing the activity of cloxacillin (MIC 120 μg/mL). Similarly, against S. aureus, compounds 178d and 178e demonstrated superior activity with MIC values of 100 μg/mL and 95 μg/mL, respectively, compared to cloxacillin (MIC 100 μg/mL). Structure-activity relationship analysis revealed that the presence of electron-withdrawing groups (F, Cl) and para-substitution on the phenyl rings generally enhanced antibacterial activity. In conclusion, this study presents a series of novel N3, N5-di(substituted)isoxazole-3,5-diamine derivatives with promising antibacterial activity against both Gram-negative and Gram-positive bacteria

Imidazolium, pyridinium and pyrazinium based ionic liquids with octyl side chains as potential antibacterial agents against multidrug resistant uropathogenic E. coli

Bacterial infections, including those caused by Pseudomonas aeruginosa, often lead to sepsis, necessitating effective antibiotic treatment like carbapenems. The key pharmacokinetic/pharmacodynamic (PK/PD) index correlated to carbapenem efficacy is the fraction time of unbound plasma concentration above the minimum inhibitory concentration (MIC) of the pathogen (%fT > MIC). While multiple targets exist, determining the most effective one for critically ill patients remains a matter of debate. This study evaluated meropenem's bactericidal potency and its ability to combat drug resistance in Pseudomonas aeruginosa under three representative PK/PD targets: 40% fT > MIC, 100% fT > MIC, and 100% fT > 4× MIC. The hollow fiber infection model (HFIM) was constructed, validated, and subsequently inoculated with a substantial Pseudomonas aeruginosa load (1 × 108 CFU/mL). Different meropenem regimens were administered to achieve the specified PK/PD targets. At specified intervals, samples were collected from the HFIM system and subjected to centrifugation. The resulting supernatant was utilized to determine drug concentrations, while the precipitates were used to track changes in both total and drug-resistant bacterial populations over time by the spread plate method. The HFIM accurately reproduced meropenem's pharmacokinetics in critically ill patients. All three PK/PD target groups exhibited a rapid bactericidal response within 6 h of the initial treatment. However, the 40% fT > MIC and 100% fT > MIC groups subsequently showed bacterial resurgence and resistance, whereas the 100% fT > 4× MIC group displayed sustained bactericidal activity with no evidence of drug resistance. The HFIM system revealed that maintaining 100% fT > 4× MIC offers a desirable microbiological response for critically ill patients, demonstrating strong bactericidal capacity and effective prevention of drug resistance.

Croton campestris A., popularly known as “Velame do campo” (Euphorbiaceae), is a shrub originating from Brazil, mainly present in the Southeast and Northeast regions. The objective of this study was to evaluate the antibacterial activity of the ethanol extract (EECC), hexane (HFEECC) and dichloromethane fractions (DFEECC), obtained from the ethanol extract of Croton campestris A. leaves. Antibacterial and modulating activity (on bacterial resistance) was determined by micro dilution method to identify the MIC (Minimum Inhibitory Concentration). In the antibacterial activity tests the fractions showed a MIC of ≥ 1024 µg/mL (where ≤ 128 µg/mL for MIC is considered clinically relevant). In regards to modulation of bacterial resistance, all products showed synergism when combined with antibiotic against bacterial strains. It was observed that all products potentiated the antibiotic action of all antibiotics assayed against all bacterial strains. The results indicate that the extracts and fractions obtained from Croton campestris leaves could represent an alternative source of natural products capable of modifying and interfering with bacterial resistance to aminoglycosides.

A hyphenated approach of chemical profiling, anti-bacterial assays, and molecular docking to validate the traditionally claimed anti-bacterial (Krimiroga) potential of Cyperus rotundus L.

The study aims to demonstrate the antimicrobial and disinfectant resistance phenotypes and genotypes of Escherichia coli isolates obtained from giant pandas (Ailuropoda melanoleuca). Antimicrobial testing was performed according to the standard disk diffusion method. The minimal inhibitory concentrations (MICs) of disinfectants were determined using the agar dilution method. All isolates were screened for the presence of antimicrobial and disinfectant resistance genes and further analysed for genetic relatedness by pulse-field gel electrophoresis (PFGE). Results showed that 46·6% of the isolates were resistant to at least one antimicrobial. Escherichia coli isolates showed resistance to fewer antimicrobials as panda age increased. Among antimicrobial-resistant E. coli isolates, the antimicrobial resistance genes blaCTX-M (88·2%) and sul1 (92·3%) were most prevalent. The disinfectant resistance genes emrE, ydgE/ydgF, mdfA and sugE(c) were commonly present (68·2-98·9%), whereas qac and sugE(p) were relatively less prevalent (0-21·3%). The frequencies of resistance genes tended to be higher in E. coli isolated in December than in July, and PFGE profiles were also more diverse in isolates in December. The qacEΔ1 and sugE(p) genes were higher in adolescent pandas than in any other age groups. PFGE revealed that antimicrobial resistance correlated well with sampling time and habitat. This study demonstrated that antimicrobial and disinfectant resistance was common in giant panda-derived E. coli, and the antimicrobial resistance was associated with sampling time and habitat. Escherichia coli could serve as a critical vector in spreading disinfectant and antimicrobial resistance. This is the first study that demonstrated the phenotypic and genetic characterizations of antimicrobial and disinfectant resistance in E. coli isolates from more than 60 giant pandas. Frequent transfer of pandas to other cages may lead to the dissemination of antimicrobial resistance. The study highlights the need for regularly monitoring the antimicrobial and disinfectant resistance in bacteria from giant pandas.

Background: The development of bacterial resistance to available antibiotics and increasing incidence of multiresistant bacterial infections in hospitals and in the community has necessitated the search for new antibacterial agents to treat the bacterial infection. It has long been known that metal ions are involved in biological processes of life through bonding to the heteroatoms of the heterocyclic residues of biological molecules i.e., proteins, enzymes and nucleic acids etc. The behavior of the disulfide group as a donor in transition metal complexes has not been subjected to such detailed study as a number of other donor groups. Aim: The Diallyldisulphide is one of the main constituents of Allium sativum (Garlic). The antibacterial and antifungal activity of the Garlic is due to the presence of sulphur containing compounds. The aim of the present work was to synthesize metal complexes with Diallyldisulphide. Materials and Methods: Complexation reactions between the Diallyldisulphide and the metal ions were carried out at three different pH i.e. acidic (pH 3), neutral (pH 7) and alkaline (pH 10) using three different ratios of metal ligand namely 1:1, 1:2, 1:3, respectively. Complex formation with the ligand and all the metals took place at pH 10, indicating that complexes were stable at this pH. Studies with different metal: ligand ratio showed that in case of silver the complexation took place at 1:1 ratio. In case of divalent metals, the appropriate ratio of metal: ligand was 1:2. The structures of the new complexes obtained were determined by spectroscopic methods. Results and Discussion: Synthesized complexes were investigated for antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae and E.coli. Diallyldisulphide-silver complex exhibited significant antibacterial activity (MIC 100 μg/ mL), and was found to be effective against selected organisms. The results concluded that the metal complexes are better antibacterial agents as compared to the silversulphadiazine. Key words: Antibacterial activity, complexes, diallyldisulphide, garlic, minimum inhibitory concentration