Agar Disc Diffusion Research Articles

Phytochemical Properties and In vitro Antimicrobial Activity of Methanolic Leaf Extract of Durio zibethinus Murr. on Selected Clinical Isolates

Bacterial and viral infections represent the most challenging diseases to treat in humans due to resistance to most of the therapeutic agents. The advent of drug resistance factors that have challenged the effectiveness of all antimicrobial agents prompted the investigation of antimicrobial activity studies of the methanolic leaf extract of Durio zibethinus Murr. This study is focused on evaluating the phytochemical and antimicrobial activity of the leaf extract of D. zibethinus Murr. on selected clinical isolates: Staphylococcus aureus and Staphylococcus epidermidis (gram-positive bacterial strains), Klebsiella pneumonia, Escherichia coli, Salmonella typhi (gram-negative bacterial strains) while Candida albicans and Microsporum audouinii (fungi strains) using the standard agar disc diffusion technique. Alkaloids, saponins, flavonoids, terpenoids, steroids, glycosides, and phenolic chemicals have all been identified via phytochemical investigation. The result indicated that the leaf extract exhibited antimicrobial activity against Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia, Candida albicans and Microsporum audouinii at a range of 10.34–16.02 mm at a concentration of 150 mg/mL relative to standard gentamicin and fluconazole antibiotics. The minimum inhibitory concentration (MIC) for S. aureus was 0.250 mg/mL; for E. coli, it was 0.125 mg/mL; whereas it was 0.250 mg/mL for the two fungal strains, C. albicans and M. audouinii. Our investigation revealed that the D. zibethinus Murr. leaf extract exhibited the highest antibacterial activity against S. aureus and E. coli whereas the extract exhibited the highest antifungal activity against M. audouinii. Our research concluded that the Durio zibethinus Murr. leaf extract had potent antibacterial and antifungal properties, suggesting that it could be utilized to treat various pathogenic diseases.

DEVELOPMENT OF THE PHARMACEUTIC CRYSTALLIZATION PROCESS USING PLASMODIUM FALCIPARUM, A DERIVATIVE OF THIOSEMICARBAZONE

Objective: The current study was designed with the goal of analyzing novel derivatives of organic and semi-organic NLO molecules that are just entering this field as the foundation for future therapeutic development. Methods: Thiosemicarbazones (TSC) are semicarbazide analogs that have sulfur atoms in place of oxygen atoms. The greatest number of therapeutic treatments for various disorders are also being used carbonyl compounds. These two types of organic compounds were combined, and their replacement with crystal growth procedures using solution growth was tested as an antibiotic for a few fastidious and nonfastidious species. The preparation of meta-substituted benzaldehydes using TSC. Tests were conducted with this single component. The following experimental technique was used to determine the antibacterial activity of Plasmodium falciparum. Half-inhibitory maximum (IC50) by calculation technique, cell viability % calculation method, and MTT assay by colorimetric method. Results: Method using agar discs. Using the agar disc diffusion method to measure the inhibition zone width and comparing the minimal inhibitory concentration (MIC) and inhibition zone width of available antibiotics against the aforementioned organism using data from the EUCAST and NCCLS databases, The absolute, relative, and mound slope values of an antibiotic that is currently on the market may be determined using the GraphPad Prism software; the epidemiological cutoff value can be determined using the ECOF Finder software; and the nature of the antibiotic can be determined using the WHONET 5.6 software. The newly developed antibiotics’ size and structure are contrasted with the structures of commercially available antibiotics and living organisms. Conclusion: The design of new drugs using novel derivatives of organic and semiorganic NLO molecules is based on the in vitro method of analysis, which has recently been introduced to this field. P. falciparum has an extremely low MIC value (0.625 μg/mL) against TSCMNB. The MIC break points are always larger than, not equal to, the MIC values and fall within the range of 110 μg/mL–130 μg/mL. We concluded that all of the novel compounds exhibit a susceptible form of inhibition.

Antibacterial and Antioxidant Efficacies of Secondary Metabolites from the Roots of Cyphostemma adenocaule: A Combined In Vitro and In Silico Study.

Cyphostemma adenocaule is a therapeutic plant traditionally used to treat rabies, snake bite, diarrhea, and wound healing. To address the bioactive compounds exhibiting these activities, we performed a comprehensive study on the roots of the plant. Thus, the present study aims to inspect the in vitro antioxidant and antibacterial efficacies of compounds isolated from the combined dichloromethane : methanol (1 : 1) and methanol extracts of C. adenocaule along with the in silico study of their interaction with selected protein targets. The silica gel column chromatography technique was used for the isolation of compounds, and the antibacterial and antioxidant activities were evaluated using agar disc diffusion and DPPH radical scavenging assays, respectively. Furthermore, in silico molecular docking screening, pharmacokinetics, and toxicity protocols of the compound isolates were performed to offer the potential applications of the compounds in developing novel medications. A BIOVIA Discovery Studio in combination with AutoDock Vina 4.2 software, SwissADME, and ProTox-II prediction web tools were used to generate the molecular docking, pharmacokinetics, and toxicity profiles, respectively. Notably, the chromatographic separation of the combined extracts yielded six known compounds, namely, β-sitosterol (1), 3-hydroxyisoagatholactone (2), ε-viniferin (3), myricetin (4), tricuspidatol A (5), and parthenocissin A (6). The in vitro antibacterial activities revealed the highest inhibition zone by tricuspidatol A (5) (16.67 ± 0.47), showcasing its potent activity against S. aureus at 2 mg/mL, compared to ciprofloxacin (21.50 ± 0.41). ε-Viniferin (3) (IC50: 0.32 μg/mL) exhibited greater antioxidant activity than the others and displayed promising results compared to ascorbic acid (0.075 μg/mL). The molecular docking study revealed the highest binding affinity by ε-viniferin (3) (-9.9 kcal/mol) against topoisomerase II α. 3-Hydroxyisoagatholactone (2) and ε-viniferin (3) fulfilled Lipinski's rule with no violation, and the organ toxicity predictions revealed that all the compounds showed no cytotoxicity and hepatotoxicity effects. Thus, this study's combined in vitro and in silico outcomes suggest the potential use of the isolated compounds in drug discovery and support the traditional relevance of C. adenocaule.

Antimicrobial resistance patterns, virulence genes, and biofilm formation in enterococci strains collected from different sources

BackgroundCurrently, antibiotic-resistant strains of Enterococcus are considered to be one of the critical health challenges globally. This study aimed to investigate the antibiotic susceptibility pattern, biofilm formation capacity, and virulence genes of enterococci isolated from different sources.MethodsIn this cross-sectional study, environmental and fecal samples were collected from the hospital environment, volunteers, and hospital staff from October 2018 to August 2019. The isolates were identified by morphological and biochemical tests (gram staining, catalase, bile resistance, esculin hydrolysis, carbohydrate fermentation, growth in 6.5% NaCl, Pyrrolidonyl arylamidase, arginine dehydrolase), and PCR for ddl gene. An antimicrobial susceptibility test was performed by the standard disk agar diffusion method according to the Clinical and Laboratory Standards Institute (CLSI) guidelines. Quantitative microplate assays were used to assess biofilm production. The bacterial DNAs were extracted by alkaline lysis method and polymerase chain reaction technique was used detect the esp, ace, and efaA virulence genes.ResultsOut of 145 isolates, 84 (57.9%) were identified as E. faecalis and 61 (42.1%) as E. faecium. Resistance to kanamycin and quinupristin-dalfopristin was 82.1% (69/84) and 85.7% (72/84), respectively, in E. faecalis isolates. Out of 61 E. faecalis isolates, 38 (62.4%) were resistant to kanamycin. Among the E. faecalis isolates, esp was the most dominant virulence gene (73.80%), followed by efaA, and ace, which were detected in 60.71%, and 30.95% isolates, respectively. In total, 68.27% of the strains were biofilm producers. Further, esp and efaA genes were more frequently found among E. faecalis strains with moderate and strong biofilm biomass.ConclusionsAccording to the findings of our study, enterococci strains isolated from different samples possess distinctive patterns of virulence genes. The esp, ace, and efaA genes were more prevalent among E. faecalis than E. faecium. Besides, the high level antibiotic resistance of normal flora and environmental enterococci strains is alarming the researchers.

A Comparative Evaluation of Herbal Extracts and Triple Antibiotic Paste as Intracanal Medicament against Enterococcus faecalis: A Microbiological Study.

The purpose of the study is to compare and evaluate the efficacy of herbal extracts over modified triple antibiotic paste (MTAP) as intracanal medicaments against Enterococcus faecalis (E. faecalis). Ginger, turmeric, and nutmeg extract were checked for antibacterial activity by agar disk diffusion method at 100, 50, 25, and 12.5% concentration. Combination groups were prepared, and the combination group showing the best zone of inhibition was further evaluated. A total of 103 samples were taken and divided into five groups: group I-MTAP, group II-ginger, group III-turmeric, group IV-nutmeg, and group V-saline. Based on different concentrations, the groups were again subdivided into subgroups at 100, 50, 25, and 12.5%. Combination groups of ginger + nutmeg, ginger + turmeric, and turmeric + nutmeg were made and evaluated. The combination group showing the best zone of inhibition was again divided into 100, 50, 25, and 12.5% and further evaluated. Modified triple antibiotic was effective in the elimination of E. faecalis. Herbal extracts showed a reduction in the number of E. faecalis. Nutmeg showed a reduction in E. faecalis, followed by ginger, followed by turmeric. This study shows that the combination of ginger + nutmeg at 12.5% concentration (35 mm) showed the highest zone of inhibition among all the herbal combinations, which is almost equal to that of MTAP. Golla S, Gambhir N, Gupta N, et al. A Comparative Evaluation of Herbal Extracts and Triple Antibiotic Paste as Intracanal Medicament against Enterococcus faecalis: A Microbiological Study. Int J Clin Pediatr Dent 2024;17(3):285-290.

Hyperbranched polyglycidol grafted with rosin by a natural catalyst under ultrasound: Synthesis, characterization and antimicrobial activity

This study aimed to apply a novel green polymerization process to produce a new copolymer with potential antimicrobial activity for industrial application. The glycidol was polymerized into hyperbranched polyglycidol (HPG) polymer which in turn has been esterified with rosin to produce hyperbranched copoly(glycidol-Rosin) (HPGR), a new co-polymer. The process used Maghnite-H+, a montmorillonite silicate sheet clay, as an eco-catalyst and ultrasound was applied to enhance the interaction during polymerization. Different catalyst amounts were tested to assess their effects on the polymerization process. Fourier Transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA) were used to analyze the polymer products. The antimicrobial activity of HPGR was assessed against six human standard microbial strains using the agar disc diffusion method. The catalyst percentage of 10% resulted in the best yield for HPGR (35%). Thermogravimetric Analysis (TGA) revealed a best thermal stability of HPGR compared to that of HPG. The HPGR co-polymer displayed the best antibacterial activity against Klebsiella pneumonia, Bacillus cereus, Staphylococcus aureus, and Escherichia coli, producing inhibition zones of 12.33 ± 0.57, 11.00 ± 1.00, 10.66 ± 1.15, and 10.33 ± 1.15 mm, respectively. The hyperbranched copoly(glycidol-Rosin), an eco-catalyst-synthesized co-polymer, displayed interesting physical and antimicrobial properties for industrial application.

Investigation of Antimicrobial Activity of Aloe vera and it’s Application

Aloe vera consists of about 420 species, and has been used as a traditional medicine for about 3000 years. The preliminary phytochemical screening of the aloe vera gel powder revealed the presence of steroids, phenolics, glycosides, alkaloids, flavonoids, saponins and tannins. Invitro antibacterial studies on the leaf extract were carried out on medically important bacterial strains, including Bacillus subtilis, Candida albicans using agar disc diffusion method. The bacterial strains were exposed to the following four different concentrations of extracts: 25µl, 50 µl, 75 µl and 100 µl. The result of our antibacterial assay revealed that the extract showed good inhibitory activity against all the tested pathogens.

Multidrug resistant profiles of clinical isolates of Escherichia coli, Salmonella typhi and Shigella species

In order to determine the antibiotic susceptibility pattern and multi antibiotic resistance index of E.coli, Salmonella typhi and Shigella species, a total of 32 pre-identified clinical isolates were obtained and subjected to conventional biochemical and gram staining reaction for confirmation. Antibiotic susceptibility testing to ten commonly prescribed antibiotics (Amplicin (PN:30 mcg), Gentamicin (GEN:10 mcg), Streptomycin (STR:30 mcg), Septrin (SXT:30 mcg), Nalidixic acid (NAL:30 mcg), Ciprofloxacin (CIP:10 mcg), Augmentin (AU:30 mcg), Reflacin (PEF:10 mcg), Tarivid (OFX:10mcg), and Ceporexin (CEP:10 mcg) was considered using disc agar diffusion method and reported with the Clinical and Laboratory Standard Institute Interpretative chart. Zones of inhibition were measured and Multiple Antibiotic Resistance index was calculated. Salmonella isolates demonstrated a high rate of susceptibility to Tarivid (90%), Reflaxin (90%), Gentamycin (80%), ciprofloxacin (60%), Augmentin (80%) and moderately susceptible to Streptomycin (40%) and Septrin (20%) with high resistance to Nalidixic acid (90%), Amplicin (90%) and Ceporexin (70%). Nearly all Shigella isolates were susceptible to Augmentin (80%), Reflaxin (90%), Tarivid (80%), intermediate susceptibility was also noted in Streptomycin (40%) and Ceporexin (50%) while high resistance to ciprofloxacin (80%), Amplicin (90%), Septrin (70%) and Nalidixi acid (90%). High rate of resistance was observed to nearly five antibiotics in E,coli with low susceptibility rate to all the antibiotics tested. All the isolates had Multiple Antibiotic Resistance index greater than 0.2 and above. This may be as a result of previous exposure to antibiotics and development of resistance to commonly prescribed antibiotics, hence, antimicrobial susceptibility testing is imperative in selecting therapeutic options.

Exploring the Antifungal Activity of Various Natural Extracts in a Sustainable Saccharomyces cerevisiae Model Using Cell Viability, Spot Assay, and Turbidometric Microbial Assays

Saccharomyces cerevisiae is a sustainable yeast with many applications in the food industry. Here, we study the use of a Saccharomyces cerevisiae model composed of three different industrial strains (a wine, a beer and a baker’s strain) to assess the antifungal activity of three organic plant-based extracts (Hypericum perforatum 10% w/w, Pistacia lentiscus var. Chia 20% w/w and Rosmarinus officinalis 6% w/w). Three different methods were employed (agar disc diffusion, spot assay, and growth curve analysis). Only the Rosmarinus officinalis extract (6% w/w) exhibited inhibitory activity against all the tested yeast strains in the agar disc diffusion method. In the spot assay, all extracts and their carrier oils (sunflower oil and caprylic triglyceride) exerted similar mild antifungal activity. In the growth curve analysis, all extracts significantly lowered the growth rate of the yeasts, but this was not observed for the carrier oils. The results highlighted that it is important to consider more than one method for testing the antimicrobial activity of different compounds. The three yeast strains exhibited differences in their susceptibility to pharmaceutical antifungals, and the beer and baker’s yeasts were resistant to itraconazole. Moreover, polyphenols were detected in all natural extracts which may be linked to their antifungal activity. Our results suggest that we might consider multiple use of these natural extracts in the food industry as food additives or even preservatives to delay food spoilage.

Genomic insights into an extensively drug-resistant and hypervirulent Burkholderia dolosa N149 isolate of a novel sequence type (ST2237) from a Vietnamese patient hospitalised for stroke

Burkholderia dolosa is a clinically important opportunistic pathogen in inpatients. Here we characterised an extensively drug-resistant and hypervirulent B. dolosa isolate from a patient hospitalised for stroke. Resistance to 41 antibiotics was tested with the agar disc diffusion, minimum inhibitory concentration, or broth microdilution method. The complete genome was assembled using short-reads and long-reads and the hybrid de novo assembly method. Allelic profiles obtained by multilocus sequence typing were analysed using the PubMLST database. Antibiotic-resistance and virulence genes were predicted in silico using public databases and the 'baargin' workflow. B. dolosa N149 phylogenetic relationships with all available B. dolosa strains and Burkholderia cepacia complex strains were analysed using the pangenome obtained with Roary. B. dolosa N149 displayed extensive resistance to 31 antibiotics and intermediate resistance to 4 antibiotics. The complete genome included three circular chromosomes (6 338 630 bp in total) and one plasmid (167 591 bp). Genotypic analysis revealed various gene clusters (acr, amr, amp, emr, ade, bla and tet) associated with resistance to 35 antibiotic classes. The major intrinsic resistance mechanisms were multidrug efflux pump alterations, inactivation and reduced permeability of targeted antibiotics. Moreover, 91 virulence genes (encoding proteins involved in adherence, formation of capsule, biofilm and colony, motility, phagocytosis inhibition, secretion systems, protease secretion, transmission and quorum sensing) were identified. B. dolosa N149 was assigned to a novel sequence type (ST2237) and formed a mono-phylogenetic clade separated from other B. dolosa strains. This study provided insights into the antimicrobial resistance and virulence mechanisms of B. dolosa.

Antibacterial activity for Tin-cephalexin Schiff bases against Bacillus Pumilus and Candida albicans

In the current study, cephalexin and two beta-lactam antibiotics were combined with four distinct aldehydes: 3-hydroxybenzaldehyde, 4-dimethylaminobenzaldehyde, 4-methoxybenzaldehyde, and 4-bromobenzaldehyde, to synthesize Schiff bases. The reaction between the free amino group of the acylamino side chain and the aldehydes resulted in the formation of four Schiff bases within the medication. Comprehensive characterization and surface examination were performed on each Schiff base. The biological activity of the synthesized compounds against Bacillus Pumilus (Gram-positive bacteria) and Candida albicans (fungus) was evaluated using the agar diffusion disc method. The antibacterial screening tests revealed that the Schiff bases exhibited enhanced antibacterial activity against these microorganisms, indicating superior efficacy compared to the parent drugs. However, no significant inhibitory effect on the tested fungus was observed.

Screening of the Leaf Extracts of Culinary Herbs (Apium graveolens, Petroselinum crispum, Cichorium endivia, and Anethum graveolens) for Their Antibacterial Activity Against Escherichia coli.

In the current era, infectious diseases pose a significant global challenge, primarily attributed to the widespread and prolonged use of antibiotics, which develop antimicrobial resistance. A significant proportion of pharmaceutical agents utilized globally can be traced back to plant origins, constituting approximately 25%. Medicinal applications harness a wide spectrum of plant-derived components, including flowers, leaves, stems, fruits, roots, waxes, oils, bioactive compounds, phytochemicals, and various other constituents. Our experiment evaluated the antibacterial activity of four different culinary plant leaf extracts. These extracts were prepared using four different solvents and were investigated against the gram-negative bacteria Escherichia coli DH5α using agar well diffusion and agar disc diffusion methods by measuring the zone of inhibition. The aqueous extract of all leaves did not show any antibacterial activity, likely due to poor diffusion due to the formation of a precipitate. Conversely, Cichorium endivia has shown the highest antibacterial activity in isopropanol as compared to other herbs. Among the herbs examined, organic extracts from endives and soybeans have demonstrated notably strong antibacterial activity compared to the other herbs. Conducting a systematic screening of leaf extracts from various culinary herbs to assess their antibacterial effectiveness against E. coli has produced encouraging and noteworthy results. In the investigation of various herbs, organic extracts derived from endives and soybeans have exhibited particularly robust antibacterial efficacy when compared to other herbal extracts.

Exploring the Antibacterial Potential of Platymiscium pinnatum

Antibiotic resistance is a growing concern worldwide, necessitating the exploration of alternative antimicrobial agents. Platymiscium pinnatum (Jacq), a tree belonging to the Fabaceae family, has traditionally held medicinal value, especially in the form of leaf infusions for treating skin and eye infections. This study delves into the antibacterial potential of the ethanolic extract obtained from the bark of P. pinnatum. Using the established Kirby-Bauer agar disk diffusion method, the antibacterial activity of the extract was assessed against both Gram-positive and Gram-negative bacteria. Results indicated a pronounced inhibitory effect on several Gram-positive strains, with Staphylococcus aureus demonstrating the highest susceptibility. This signifies the potential of the extract as a therapeutic agent against infections caused by Gram-positive bacteria. On the contrary, the bioactivity of the extract was comparatively limited against prominent Gram-negative strains, such as E. coli and Pseudomonas aeruginosa. The differential activity between Gram-positive and Gram-negative bacteria could provide insights into the mode of action or specific compounds within the extract. The distinctive antibacterial properties of the P. pinnatum bark extract highlight its potential as a source for developing novel antimicrobial agents. These findings pave the way for further phytochemical analyses and studies to understand the specific bioactive components responsible for the observed effects.

Antioxidant, Immunomodulatory and Fungicidal Potential of Different Extracts of Raphanus Raphanistrum L. Var. Caudatus

Background: Reactive oxygen species (ROS) have been implicated in the pathogenesis of various diseases, emphasizing the importance of antioxidants in maintaining cellular homeostasis. Raphanus raphanistrum, commonly known as wild radish, has been traditionally used for its medicinal properties, including antioxidant, immunomodulatory, and antifungal effects. The plant is rich in bioactive compounds such as flavonoids, isothiocyanates, and vitamins, which contribute to its therapeutic potential. Objective: This study aimed to evaluate the antioxidant, immunomodulatory, and antifungal activities of Raphanus raphanistrum extracts and to compare these activities with standard controls. Methods: Fresh Raphanus raphanistrum plants were collected, and extracts were prepared using methanol, chloroform, and water. The antioxidant activity was assessed using the DPPH radical scavenging assay. Immunomodulatory activity was evaluated through the luminol-enhanced chemiluminescence assay in whole blood and polymorphonuclear leukocytes (PMNS), measuring the oxidative burst. The antifungal activity was determined using the agar disk diffusion method against six pathogenic fungi. The statistical analysis was performed using SPSS version 25, with results presented as mean ± standard deviation for antioxidant and antifungal assays, and mean ± standard error for immunomodulatory activity. Results: The methanol extract exhibited significant antioxidant activity with DPPH scavenging percentages ranging from 56.55% at 150 µg/ml to 87.08% at 850 µg/ml. Immunomodulatory activity showed IC50 values of 37.8 µg/ml in whole blood and 18.9 µg/ml in PMNS for the methanol extract. The antifungal activity against Candida albicans showed zones of inhibition increasing from 15 mm at 150 µg/ml to 22 mm at 850 µg/ml. These activities were compared to standard controls, including ascorbic acid for antioxidant, ibuprofen for immunomodulatory, and miconazole for antifungal assays, demonstrating the extracts' competitive potential. Conclusion: Raphanus raphanistrum extracts showed promising antioxidant, immunomodulatory, and antifungal activities, indicating their potential as natural alternatives for the prevention and treatment of related diseases. Further in vivo studies and isolation of active compounds are recommended to fully understand the mechanisms and therapeutic applications.

Antibacterial Activity and Shear Bond Strength of Orthodontic Adhesive Containing Various Sizes of Chitosan Nanoparticles: An In Vitro Study.

White spot lesions are common after orthodontic treatment. Chitosan nanoparticles (CS-NPs) have emerged as promising antibacterial agents that inhibit the growth of Streptococcus mutans. The aim of the study was to investigate the nano-effect of adhesives containing CS-NPs on S. mutansand their effects on shear bond strength. The inhibitory effects of two sizes of CS-NPs were assessed using the disc agar diffusion method. Four wells were created in the petri dishes, and each was inoculated with broth (negative control), chlorhexidine (positive control), CS-NPs (20 nm), or CS-NPs (131 nm). An Instron machine was used to evaluate shear bond strength by allocating 24 teeth into three groups, and all measurements were recorded in megapascals. Caries progression was assessed using the International Caries Detection and Assessment System and surface profilometry. Statistical analysis was performed using IBM SPSS Statistics for Windows, Version 27.0 (Released 2020; IBMCorp., Armonk, New York, United States) for a one-way ANOVA followed by Tukey's multiple comparison test. Disc agar diffusion showed a reduction in S. mutans in the CS-NPgroup compared to the control (p < 0.001), with no statistical significance between the sizes of 20 and 131 nm (p = 0.95). Regarding shear bond strength, no differences were recorded when adhesive-containing CS-NPs and the control were compared (p = 0.44). Additionally, no differences were found within the CS-NP groups (p = 0.91). Caries assessments showed excellent agreement, as indicated by a weighted kappa. Profilometry readings showed higher surface roughness in the control than in the CS-NP groups (p < 0.001), with no statistically significant difference between the CS-NP groups (p = 0.72). CS-NPs of both sizes tested had similar antibacterial effects. In addition, the incorporation of CS-NPs did not affect shear bond strength.

Antibacterial and Antioxidant Activities of Triterpenoids and Cyclic 1,7-Diarylheptanoids from the Stem Bark of Myrica salicifolia: A Combined Experimental and Computational Study

Myricasalicifolia A Rich (Myricaceae) is a tree growing in Central and East Africa. Traditionally, the plant is used to treat malaria, respiratory disorders, inflammations, and infections. A new compound, 3β-O-trans-caffeoylisomyricadiol (7), was isolated from MeOH : CHCl3 (2 : 1) extract of the stem bark of Myrica salicifolia along with seven known compounds, namely, myricanone (1), myricanol (2), myricanol-11-O-β-D-xylopyranoside (3), taraxerone (4), taraxerol (5), myricadiol (6), and methyl-β-D-glucopyranoside (8). This is the first report of the isolation of taraxerene-type triterpenes from this plant. The structures were determined by a comprehensive analysis of 1D/2D NMR spectroscopy, HR-MS, and by comparison with literature data. The compounds showed a wide range of DPPH scavenging activities from very weak (IC50 value = 282.61 μM) to very strong (IC50 = 13.48 μM). Antibacterial activities of the compounds were evaluated using the disk diffusion agar method, where some of the compounds showed modest antibacterial activities against S. pyogenes and S. aureus at 250 μg/mL. Compounds 2, 3, and 7 were assessed for their in silico molecular docking analysis. The lowest binding affinity for compound 7 was found to be −7.26 to −10.35 kcal/mol against PqsA protein of P. aeruginosa, pyruvate kinase (PK) enzyme of S. aureus, LuxS protein of S. pyogenes, and DNA gyrase B of E. coli, which showed better binding affinity compared to the standard drug ampicillin (−7.36 to −8.03 kcal/mol) and ciprofloxacin (−6.19 to −6.83 kcal/mol). In silico ADMET predictions revealed that compounds 3 and 8 met all the requirements for pharmacokinetic properties.

Characterization of heavy metal-associated bacteria from petroleum-contaminated soil and their resistogram and antibiogram analysis.

The aim of the current study was to screen and identify heavy metal (chromium, cadmium, and lead) associated bacteria from petroleum-contaminated soil of district Muzaffarabad, Azad Jammu and Kashmir, Pakistan to develop ecofriendly technology for contaminated soil remediation. The petroleum-contaminated soil was collected from 99 different localities of district Muzaffarabad and the detection of heavy metals via an atomic absorption spectrometer. The isolation and identification of heavy metals-associated bacteria were done via traditional and molecular methods. Resistogram and antibiogram analysis were also performed using agar well diffusion and agar disc diffusion methods. The isolated bacteria were classified into species, i.e., B. paramycoides, B. albus, B. thuringiensis, B. velezensis, B. anthracis, B. pacificus Burkholderia arboris, Burkholderia reimsis, Burkholderia aenigmatica, and Streptococcus agalactiae. All heavy metals-associated bacteria showed resistance against both high and low concentrations of chromium while sensitive towards high and low concentrations of lead in the range of 3.0 ± 0.0mm to 13.0 ± 0.0mm and maximum inhibition was recorded when cadmium was used. Results revealed that some bacteria showed sensitivity towards Sulphonamides, Norfloxacin, Erythromycin, and Tobramycin. It was concluded that chromium-resistant bacteria could be used as a favorable source for chromium remediation from contaminated areas and could be used as a potential microbial filter.

The Study of Increasing Shelf-Life of Meat by Using Nanocellulose-Chitosan Composite Film Obtained from Agricultural By-Products

Background: This research was conducted to design a bionanocomposite film for meat packaging with regard to environmental aspects. Methods: Cellulose nanoparticles (CNPs) were used as nano-reinforcing factors were generated using non-edible agricultural by-products. The bionanocomposite film which was recently developed contains CNPs and chitosan (CS); then, the nanocomposites were explored via SEM, FTIR, agar disc diffusion tests and X-ray crystallography (XRD). Finally, the film was used to pack meat pieces. Results: Investigation of the morphological and physical reports of the solid films indicated that the CNPs are well scattered in bionanocomposite film. The addition of CNPs within a CS improved Young’s modulus by about 12135% and the tensile strength by 583%. In addition, XRD photographs indicated that CNP peak appeared after being added to CS context. Antimicrobial activity demonstrated that nanocomposites exerted restrictive effect on Escherichia coli, Pseudomonas aeruginosa, Listeria monocytogenes, and Staphylococcus aureus bacteria. Using CS-nanocellulose composite as a packing film on meat surface leads to decreasing bacteria growth compared to nylon packing materials at 4˚C after 8 days of storage. Conclusion: Findings indicated that the recently designed CNP-CS films are a better replacement for common food packaging substances.

Physicochemical Profiles and Antimicrobial Activity of Ozonated Palm Kernel Oil

ABSTRACT Palm kernel oil (PKO) is a vegetable oil containing active substances beneficial for medicine and health. The applications of PKO can be extended by synthesizing ozonated PKO (OPKO). In this study, the PKO was ozonated at different intervals (0, 1, 3, 7, and 24 h). The physicochemical properties of OPKO were studied, including iodine value (IV), peroxide value (PV), acid value (AV), anisidine value (p-AV), viscosity and fatty acid composition (FAC). Meanwhile, the spectroscopic characteristics, melting and crystallization properties of OPKO were also investigated. Besides, the present study also examined the antimicrobial properties of OPKO against Gram-positive and Gram-negative bacteria as well as fungi using agar disk-diffusion method. The results showed that PV, AV, and viscosity of the OPKO increased in parallel with increasing ozonation time, reaching 963.6 ± 25.0 meq O2/kg fat, 45.30 ± 1.45 mg KOH/g oil, and 196.3 ± 1.6 mPa.s, respectively, after 24 h of ozonation. On the other hand, prolonged ozonation time reduced oleic acid and led to lower IV of 1.6 ± 0.7 g I2/100 g oil. The p-AV exhibited an increasing-decreasing trend, reaching a peak at 3 h ozonation period. Spectroscopic analysis showed that the absorption band at 1712 cm−1, 1400 cm−1, and 1112 cm−1, attributed to C=O, O-H, and -C-O, respectively, were altered with the ozonation time, indicating the change in the chemical composition of PKO. Moreover, the change in the FAC also affected the crystallization and melting profiles of PKO. This work also demonstrated the excellent antimicrobial properties of OPKO with significant inhibition effects against several types of microorganisms tested. Therefore, OPKO can be an essential component with great potential for cosmetics and pharmaceutical products.

Agreement of methods to assess antimicrobial susceptibility using Escherichia coli isolates as target models.

Antimicrobial susceptibility tests (AST) conducted in vitro offer a range of methods to assess the antimicrobial resistance (AMR) of microorganisms. Escherichia coli, a widely distributed bacterium, is closely linked to the issue of AMR. In this way, the present study aimed to assess the agreement among different in vitro AST methods, including disk diffusion in agar, broth dilution, and agar dilution method. A total of 100 E. coli isolates were analyzed for their resistance levels against six antibiotics: amoxicillin, ceftiofur, ciprofloxacin, chloramphenicol, tetracycline, and sulfamethoxazole+trimethoprim, using the aforementioned AST methods. Standard breakpoint values were employed to classify isolates as resistant, intermediate, or susceptible, and comparisons among the AST methods were conducted by McNemar's test (P<.05). The obtained data demonstrated equivalence among the AST methods, highlighting the reliability of these standardized classical methodologies. This standardization aids in preventing the inappropriate use of antimicrobials and the dissemination of antimicrobial-resistant microorganisms.