Human Pathogenic Bacterial Strains Research Articles

Optimization of Culture Conditions and Batch Process Control for the Augmented Production of Bacteriocin by Bacillus Species.

The emergence of antibiotic-resistant microorganisms poses a significant threat to human health worldwide. Recent advances have led to the discovery of molecules with potent antimicrobial activity from environmental sources. In this study, fifteen bacterial isolates were obtained from agricultural and polluted soil samples collected from different areas of the cities of Jizan and Jeddah. These isolates were screened for antagonistic activity against a set of human pathogenic bacterial strains. The results showed that two Bacillus strains, identified as Bacillus atrophaeus and Bacillus amyloliquefaciens based on 16S rDNA, synthesized bacteriocin with strong antibacterial activity against Methicillin-resistant Staphylococcus aureus (MRSA) ATCC 33591, Pseudomonas aeruginosa ATCC 9027, Salmonella typhimum ATCC 14028, carbapenem-resistant E. coli, and MRSA 2. To optimize bacteriocin production, the effects of medium composition, incubation period, temperature, and pH were investigated. Nutrient broth and Mueller-Hinton broth were chosen as the optimal original media for bacteriocin production. The optimal incubation period, temperature, and pH were found to be 48 h at 37 °C and 7 pH in Bacillus atrophaeus and 72 h at 37 °C and 8 pH in Bacillus amyloliquefaciens. Batch cultures of Bacillus atrophaeus and Bacillus amyloliquefaciens were grown in a 10 L benchtop bioreactor, and pH control was found to significantly increase the production of bacteriocin by two-fold compared to uncontrolled conditions. The time course of growth, substrate consumption, pH, and enzyme production were investigated. This study demonstrates the potential of optimizing culture conditions and batch process control to enhance bacteriocin production by Bacillus spp.

Phytochemical Composition, Antioxidant and Antibacterial Studies on Celtis Timorensis Leaf Extract

Objective: The objective of the present investigation is to study the phytochemical composition, antioxidant and antibacterial activity of petroleum ether, chloroform, ethanol, methanol and water extracts of the leaf part of Celtis timorensis Spr. The preliminary phytochemical studies were conducted according to standard procedures. Total phenolic content was estimated using the FCA reagent method. The antioxidant efficiency of extracts was evaluated by using molybdate and DPPH methods. The antibacterial potency of leaf extracts was studied using the disc diffusion method against eight human pathogenic bacterial strains. Results: The results of preliminary phytochemical study revealed the presence of alkaloids, phytosterols, phenolic components, tannins, flavonoids, terpenoids, glycosides and saponins. The total phenolic content of the tested extracts exhibited a range between 8.82 to 68.32 mg GAE/g dwt. The highest total phenolic content was observed in the methanol extract (68.32±1.03 mg GAE/g dwt.) and the highest total antioxidant capacity was observed in the methanol extract of leaf part (700.0±0.71 mg ASE/g dwt.).Regarding DPPH scavenging activity the highest DPPH-reducing activity (>90%) was observed by methanol, ethanol and water extracts of the leaf part. Ethanol and water extracts of leaf samples strongly inhibited the gram-negative bacterial species Pseudomonas aeruginosa and Salmonella enterica (13 mm for each species) respectively. While gram-positive species i.e. Bacillus megatherium Artherobacter protophormiae and P. aeruginosa were moderately inhibited by chloroform, ethanol and water extracts (12 mm for each) respectively. Conclusion: In conclusion, the selected medicinal plant C. timorensis extracts exhibited good antioxidant activity, strong antibacterial activity and rich bioactive components. It required further studies on the isolation, and characterization of active principle to evaluate its pharmacological properties.

Enhancing biological activities and phenolic content of wild grapevine roots by severe drought stress

Wild grapevines are a rich source of polyphenolic compounds. Various environmental factors can influence these bioactive metabolites, contributing to stress mitigation and adaptation. The present study aimed to investigate the impact of prolonged drought stress on the accumulation of phytochemicals, antioxidants, and antimicrobial activity in the roots of the endangered Tunisian wild grapevine (Vitis vinifera subsp. sylvestris) "Tebaba" genotype. The results revealed that under prolonged drought stress, there was a significant increase in total phenolic compounds, total flavonoid content, and stilbenes, which showed a positive and significant correlation with the total antioxidant activity. Furthermore, the ethanolic extracts demonstrated an enhanced in vitro antibacterial effect against selected human pathogenic bacterial strains, including Staphylococcus aureus, Methicillin-resistant S. aureus, and Enterococcus faecalis. The minimum inhibitory concentration (MIC) and the minimal bactericidal concentration (MBC) values, relative to prolonged drought stress, ranged from 125 to 250 µg/mL. The values of the ratio between MBC and the MIC showed that the activity of the root extract was bactericidal in all cases (MBC/MIC ≤ 2). This study highlights the potential of wild grapevine roots enriched with drought-inducible phenolic compounds, as a promising source of antimicrobial agents relevant to human health applications.

Synthesis, Antimicrobial Studies, and Molecular Docking Simulation of Novel Pyran, Pyrazole, and Pyranopyrazole Derivatives

A group of compounds containing pyran, pyrazole, and pyranopyrazole were synthesized (2–4) using a facile and convenient protocol. The structure of the synthesized compounds was elucidated by spectroscopic and elemental analysis. In vitro antimicrobial evaluation was also performed for all synthesized derivatives against human pathogenic bacterial strains such as Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis using chloramphenicol as a reference. It was depicted that compounds 3d, 4b displayed a high degree of inhibition against Bacillus subtilis and Staphylococcus aureus. Compounds 2d, 4f and 2d, 4e, 4f, and 4e had high inhibition effects against Escherichia coli and Pseudomonas aeruginosa, respectively. The molecular docking study was performed against S. aureus bacteria to rationalize the binding affinities and the feasible modes of interaction with the active site of tyrosyl-tRNA synthetase. It was found that the synthesized compounds were well fit into the binding site of tyrosyl-tRNA synthetase. The obtained results were in good accordance with the experimental data. The data obtained were promising candidates for further development of novel heterocyclic scaffolds as therapeutics with high efficacy biomedical precursors.

Polyol synthesis of one-dimensional Ag nanowires for the photocatalytic degradation of textile dye and effective removal of microbes.

Due to the excess release of hazardous pollutants to the environment, the quest for the synthesis of effective nanomaterials for wastewater treatment is never-ending. Present study reports the polyol synthesis of Ag NWs of ~ 85nm diameter and average length of 4.08µm using PVP and ethylene glycol. The experimental data on the methylene blue dye degradation substantiated the photocatalytic efficiency of Ag NWs (88% degradation in 120min). Furthermore, the Ag NWs exhibited microbial load reducing property in air conditioner condensate water (ACW) within a time period of 60min. Also, the anti-bacterial effect of Ag NWs was estimated using two human pathogenic bacterial strains, namely Staphylococcus aureus and Bacillus cereus. The antibacterial potential of Ag NWs against Staphylococcus aureus and Bacillus cereus was revealed significant with an inhibition zone size of 14 ± 0.1mm and 9 ± 0.1mm, respectively. Hence, the present work validates the potential efficiency of Ag NWs in the degradation of textile dyes and reduction of microbial population.

Deposition of Daldinia starbaeckii (ELF) functionalized silver nanoparticles on urinary catheter tube using chitosan polymer to prevent microbial biofilms formation during UTI infection.

Catheter-associated urinary tract infections (CAUTI) are the most common healthcare problem in hospitals. In this study, we isolated the Daldinia starbaeckii (An endolichenic fungus from Roccella montagnie) and its biomass extract were used to simultaneously synthesize and deposit DSFAgNPs on the inner and outer surfaces of the catheter tube using chitosan biopolymer via In-situ deposition method. Perfectly designed D. starbaeckii extract functionalized DSFAgNPs were characterized by UV spectroscopy, FTIR, SEM, EDS, TEM, and XRD. The microbial efficacy of DSFAgNPs & DSFAgNPs coated catheter (CTH3) was evaluated against eight human pathogenic gram (+ / -) ive strains and Candida albicans. Results indicated DSFAgNPs showed significant biological activity against both gram (+ / -) ive bacteria with an average MIC90 of 4µl/ml. The most promising activity was observed against Helicobacter pylori. When bacteria strains allow to grow with CTH3 we reported significant reduction in colony formation unit (CFU/ml) in broth culture assay with an average 70% inhibition. Further, antibiofilm activity of CTH3 against P. aeruginosa showed strong inhibition of biofilm formation (85%). The study explored an alternate approach for significantly prevent CAUTI among hospital patients. We isolated an endolichenic fungus from lichen Roccella montagnei. The molecular characterization of fungus identified as Daldinia starbaeckii (DSF). The DSF was cultured and its fungal biomass exudes were used to simultaneously construct DSF-AgNPs and its deposition on the catheter surface using biopolymer chitosan via In-situ deposition method. Further, antimicrobial and antibiofilm efficacy of DSF-AgNPs was checked against urinary catheter contaminating and human pathogenic bacterial strains. Based on our research, we determined that DSF-AgNPs coating on a urinary catheter through this method is a cost-effective, eco-friendly approach to prevent catheter contamination.

Antibacterial Activity and in Silico Investigation of 2-[(3-Substitutedphenyl) Azomethine] Phenol as anti-SARS-CoV-2 Mpro and anti-Plasmodium falciparum Agents

Imine derivatives are widely used in medicine for the treatment of several diseases causing human infections; we examined Schiff’s bases derivatives: 2-[(3-methylphenyl) azomethine] phenol (L1), 2-[(3-chlorophenyl) azomethine] phenol (L2) and 2-[(3-nitrophenyl) azomethine] phenol (L3) against three human pathogenic bacterial strains according to the disk diffusion test. In addition, to revealing the importances of the in silico study of these derivatives, in particular the molecular docking which is based on the protein structures: the main protease 3CL of SARS-CoV-2 and the aminopeptidase of the M1 family. Also, a molecular dynamics simulation was performed to examine the structural stability of the best docked conformation. The evaluation of the global reactivity parameters of the molecular system of Schiff base derivatives was applied by the DFT method with the hybrid functional (B3LYP)/6-31G (d) basis set. The results of the antibacterial activity showed a strong activity in the presence of the L3 ligand against Escherichia coli (ATCC 25922) with a diameter inhibition zone equal to 11 ± 0.61 mm. Molecular docking shows that the L3 ligand formed with protein targets more stable complexes by predicting interesting interactions: hydrogen, hydrophobic and electrostatic bonds with the residues of these targets 3CLpro and PfA-M1. Further, molecular dynamics simulations confirm a strong energy contribution with these interactions. Therefore, suggesting that our ligands could contribute to the development of anti-coronavirus-2 and anti-malarial drug properties.

Ribosomal DNA Sequence-Based Taxonomy and Antimicrobial Activity of Prorocentrum spp. (Dinophyceae) from Mauritius Coastal Waters, South-West Indian Ocean

Microalgae are unicellular organisms and commonly present in the euphotic zone of marine ecosystems. From the western coast of Mauritius, three strains of Prorocentrum species were isolated from macrophytes and cultured under standard laboratory conditions. Morphologies were examined by light, fluorescence, and scanning electron microscopy, and phylogenetic analyses were based on partial large subunit LSU rDNA (D1-D2) and ITS1-5.8S-ITS2 (ITS) regions. Three Prorocentrum species, including the P. fukuyoi complex, P. rhathymum, and P. lima complex, were identified. The antimicrobial activities were assayed against potential human pathogenic bacterial strains. The highest zone of inhibition was recorded for intracellular and extracellular protein extracts of Prorocentrum rhathymum against Vibrio parahaemolyticus. The polysaccharide extracts of the Prorocentrum fukuyoi complex had a higher zone of inhibition (24 ± 0.4 mm) against MRSA at a minimum concentration of 0.625 μg/mL. The extracts from the three Prorocentrum species had different levels of activity against the pathogens used, and this can be of scientific interest in the search for antibiotics from natural marine sources.

Anti-diabetic potential of water-soluble polysaccharide from okra pods mucilage diabetes

Plant derived mucilage, due its role in promoting human health, has been extensively used as active constituent for the preparation of different pharmaceuticals, functional and nutraceutical products. Mucilage mainly consists of complex carbohydrates with extremely branched structure. Abelmoschus esculentus L. (Moench), belongs to family Malvaceae, is an annual herb commonly known as okra. The purpose of this study was the identification of bioactive polysaccharides present in the mucilage of okra pods and evaluation of their biological activities. Mucilage was extracted by soaking okra pods in water. The dried mucilage was fractionated in 75% ethanol, which resulted in soluble and insoluble fractions. Each fraction was screened which confirmed the presence of galacturonic acid, saturated and unsaturated polysaccharides. Crude, soluble and insoluble fractions were processed for investigating their biological activities. The results indicated that insoluble fraction was able to inhibit the growth of five human pathogenic bacterial strains i.e. Staphylococcus aureus (1.9 mm ± 0.27mm), Escherichia coli (2.8mm ± 0.44mm) and Shigella (2.9mm ± 0.85mm). However, no significant inhibition was observed against Klebsiella pneumonia and Salmonella typhi. Antioxidant capacity was determined through DPPH assay where the soluble fraction showed IC50 value 785.5 μg/mL while the insoluble fraction showed IC50 value 987.21 μg/mL.

Synthesis of Rumex hastatus-based silver nanoparticles induced the inhibition of human pathogenic bacterial strains

The development of antibiotic resistance in pathogenic bacterial strains has drawn attention to the quest for new natural antibacterial drugs. Therefore, in the present study, extracts of Rumex hastatus leaves were obtained in methanol and water, and R. hastatus-based silver nanoparticles (AgNPs) were synthesized. Structural and functional properties of synthesized silver nanoparticles were determined by UV–vis spectroscopy, XRD, FTIR and SEM. The synthesized AgNPs and crude extracts were tested to check their antibacterial potential against human pathogenic bacterial strains of Staphylococcus aureus, Staphylococcus haemoliticus, Bacillus cereus, Escherichia coli, Salmonella typhi and Pseudomonas aeruginosa in well diffusion and broth dilution methods. The present investigation has revealed for the first time that the broth dilution method was found more reproducible than that of the well diffusion method even at lower concentrations of AgNPs and crude extracts. UV– Vis spectroscopic analysis of AgNPs revealed a peak at 367 nm. XRD pattern showed a face-centered cubical to the spherical structure of AgNP crystals. FTIR analysis revealed that flavonoids and terpenoids are responsible for the reduction of AgNO3 to Ag+. SEM analysis determined the spherical structure and 51 nm average diameter of nanoparticles. The antibacterial activity of R. hastatus-based (AgNPs) was found to be significantly higher than aqueous plant extract and silver nitrate alone. Bacterial growth was inhibited by R. hastatus-based AgNPs in a dose-dependent manner. To our knowledge, silver nanoparticles (AgNPs) of R. hastatus were synthesized and characterized for the first time in this study and, based on the findings of current research work R. hastatus extract-based silver nanoparticles are suggested to be used as an antibacterial drug instead of synthetic drugs for the treatment of various human diseases/infections caused by the tested bacterial strains.

Bioactive Compounds from Endophytic Bacteria Bacillus subtilis Strain EP1 with Their Antibacterial Activities.

Endophytic bacteria boost host plant defense and growth by producing vital compounds. In the current study, a bacterial strain was isolated from the Boswellia sacra plant and identified as Bacillus subtilis strain EP1 (accession number: MT256301) through 16S RNA gene sequencing. From the identified bacteria, four compounds-1 (4-(4-cinnamoyloxy)phenyl)butanoic acid), 2 (cyclo-(L-Pro-D-Tyr)), 3 (cyclo-(L-Val-L-Phe)), and 4 (cyclo-(L-Pro-L-Val))-were isolated and characterized by 1D and 2D NMR and mass spectroscopy. Moreover, antibacterial activity and beta-lactam-producing gene inhibition (δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine synthetase (ACVS) and aminoadipate aminotransferase (AADAT)) assays were performed. Significant antibacterial activity was observed against the human pathogenic bacterial strains (E. coli) by compound 4 with a 13 ± 0.7 mm zone of inhibition (ZOI), followed by compound 1 having an 11 ± 0.7 mm ZOI. In contrast, the least antibacterial activity among the tested samples was offered by compound 2 with a 10 ± 0.9 mm ZOI compared to the standard (26 ± 1.2 mm). Similarly, the molecular analysis of beta-lactam inhibition determined that compounds 3 and 4 inhibited the two genes (2- to 4-fold) in the beta-lactam biosynthesis (ACVS and AADAT) pathway. From these results, it can be concluded that future research on these compounds could lead to the inhibition of antibiotic-resistant pathogenic bacterial strains.

First report on isolation of Mucor bainieri from honeybees, Apis mellifera: Characterization and biological activities

Fungi are potential biocontrol agents and rich sources of secondary metabolites with demonstrated biological activities. This study aimed to isolate and identify fungi from surface-sterilized honeybees (Apis mellifera), as well as to evaluate their biological activities. One fungal isolate was obtained and identified morphologically and genetically as Mucor bainieri MK-Bee-2. Gas chromatography-mass spectroscopy (GC–MS) analysis of fungus crude extract, showed the existence of six major metabolites representing 92.48% of the total peak area. The crude extract of Mucor bainieri MK-Bee-2 was tested for antimicrobial, antioxidant, and antitumor activities. It demonstrated wide antimicrobial activities against human pathogenic Gram-positive and Gram-negative bacterial strains, as well as Candida albicans, with MIC values ranged from 62.5 to 250 µg/ml. The results revealed that the extract exhibited considerable antioxidant activities indicated by strong inhibition of both DPPH and ABTS free radicals. Additionally, the extract exhibited greater potential anticancer activity against both adenocarcinomic human non-small cell lung cancer cells (A549) [IC50 = 6.45 μg/ml], and immortal cell line hepatoma G2 (HepG2) human liver cancer cells [IC50 = 27.48 μg/ml] and higher selectivity in cancer cells than normal cell lines. Furthermore, the extract showed less cytotoxic activity against normal cells with higher IC50 values of 106.99 and 132.57 μg/ml against human lung fibroblast Wistar-38 (Wi-38) and oral epithelial cells (OEC), respectively. Taken together, the Mucor bainieri MK-Bee-2 extract comprises bioactive compounds as promising potential therapeutic candidates for the treatment of lung cancer. Strikingly, the extract sensitizes the lung cancer cells A549 to the ionizing radiation through the pro-apoptotic pathway as indicated by the annexin V flow cytometry analysis which showed that the extract induced the apoptosis of lung cancer cells.

Biosynthesis and biophysical elucidation of CuO nanoparticle from Nyctanthes arbor-tristisLinn Leaf.

Copper oxide nanoparticles (CuO NPs) synthesis using an environmentally benign approach, as well as their antibacterial properties. Copper sulphate pentahydrate (CuSO4.5H2O) of different concentrations (2mM, 5mM and 10mM) and aqueous Nyctanthes arbor-tristisleaf extract were used to make the CuO NPs. The synthesised CuO NPs are characterised by UV-vis spectroscopy, X-ray diffractometer (XRD), Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). UV-vis spectroscopy confirmed the presence of CuO NPs. The functional groups of the active components were identified using the FTIR spectra of the control (leaf extract) and CuO NPs. SEM pictures revealed that the particles were rectangular, truncated triangle and spherical in shape, with sizes ranging between 4.9nm, 18.4nm and 23.8nm determined using X-ray diffraction. The antibacterial activity of the produced CuO NPs was further evaluated using the well diffusion method. By observing inhibition zones around each well, the nanoparticles were revealed to have broad antibacterial action against human pathogenic bacterial strains Escherichia coli and Staphylococcus aureus withs the 7 ± 0.70-mm and 7 ± 0.21-mm inhibitory zone size respectively followed by 08μg/mL and 2.5μg/mL MIC respectively. Thus, these outputs concluded that the CuO NPs exhibited miraculous effect and it might be boon towards nanomedical science, pharmaceuticals and health industries. KEY POINTS: • Biosynthesis of CuO nanoparticle • Multifaceted utilization • Broad spectrum antimicrobial activity.

(NH4)2[Co(H2O)6]2V10O28·4H2O Vs. (NH4)2[Ni(H2O)6]2V10O28·4H2O: Structural, Spectral and Thermal Analyses and Evaluation of Their Antibacterial Activities

This paper presents the synthesis of two cluster compounds {(NH4)2[Co(H2O)6]2V10O28·4H2O (C1) and (NH4)2[Ni(H2O)6]2V10O28·4H2O (C2)} which were obtained as single crystals suitable for XRD analysis that revealed their crystallization in the monoclinic (C2/c) and triclinic (P-1) space groups, respectively. Additionally, C1 and C2 were characterized using CHN analysis and FT-IR spectroscopy and their thermal decomposition mechanisms were investigated. The antibacterial activities of both compounds were determined against three human pathogenic bacterial strains {Bacillus cereus ATCC 33,018, Escherichia coli O157:H7 and Pseudomonas aeruginosa ATCC 9027} and one phytopathogenic bacterial strain {Ralstonia solanacearum}, while drug standards {chloramphenicol and streptomycin} were used as control. The inhibitory activity and the minimum inhibitory concentration (MIC) values of the tested compounds clearly indicated higher antibacterial activities of the nickel compound against B. cereus ATCC 33,018, E. coli O157 and R. solanacearum with MIC values of 3.150, 3.150 and 6.300 mg/ml, respectively. On the other hand, (NH4)2[Co(H2O)6]2V10O28·4H2O exhibited higher antibacterial activity against P. aeruginosa ATCC 9027 (MIC value of 6.300 mg/ml) in comparison to the nickel analog. In general, the measured activities are lower than that obtained for the standards except for the higher activity given by C2 in comparison to streptomycin against the R. solanacearum strain.

A Green Synthesis of Nitrogen Containing Novel Tetraazaaceanthrylene Derivatives Under Catalyst‐free Conditions: Docking studies, ADME and Antibacterial Activity

AbstractA facile and convenient greener route has been introduced for the synthesis of novel 2‐phenyl‐2,3,5,6‐tetraazaaceanthrylene‐1,4(2H,5H)‐dione derivatives via one pot three component reaction of barbituric acid, substituted aryl amines and isatin with ethanol as solvent. The synthesized compounds were characterized by FT‐IR, 1H NMR and 13C NMR techniques. The remarkable features of this method are catalyst‐free, short reaction time, good yields and simple purification techniques. The effect of inhibition and possibilities of interaction of 1GQN enzyme on Salmonella typhi with synthesized compounds was explored through molecular docking approach. Pharmacokinetics profile of the synthesized compounds was explored by ADME technique. All the synthesized compounds have also been evaluated for their antibacterial activity against Gram positive and Gram‐negative bacterial strains. The compounds 4a and 4d exhibited significant effect against four human pathogenic bacterial strains with the maximum inhibition zone.

Green 2D simonkolleite/zinc based nanostructures for superior antimicrobial and photocatalytic applications

The problem of organic contamination in water, unfavorable microbial growth on food products and antibiotic resistance against human pathogenic microbes has piqued interest around the world. The goal of this research is to see how effective green 2D Simonkolleite/Zinc based nanostructures (SM-Zn NS) against various human pathogenic (bacterial and fungal strains) and their photo degradation activity. Fine 2D Nanosheets of SM-Zn NS were observed by field emission scanning electron microscopy (FESEM). X-ray diffraction validated the crystalline structure of SM-Zn NS. The disc diffusion method was used to demonstrate the bactericidal effect of SM-Zn NS. On various bacterial strains, including Microcuccus luteus (Ml), Basilus subtilis (Bs), Staph aureus (Ba), Basilus pumilus (Bp), E. coli, Pseudomonas aeruginosa (Pa), Staph epidermidis, and Bordetetella bronchiseptica (Bb), at different concentrations of SM-Zn NS (10 μg/mL, 20 μg/mL) and standard drug (Ciprofloxacin 1 mg/mlL). The antifungal activity of SM-Zn NS was demonstrated using the disc diffusion method. Aspergillus terreus, Aspergillus fumigatus, Aspergillus flavus, and Candida albican were tested using a single concentration of SM-Zn NS 20 μg/mL and the standard drug (Terbisil) 1 mg/ml. The results showed that green SM-Zn NS have significant and higher bactericidal as well as fungicidal effects against various human pathogens. Excess Cl− concentration responsible for formation of new defect energy level due to oxygen vacancies and the formation of the heterojunction between valance band and conduction band increased the photocatalytic properties of SM-Zn NS by reducing band gap which resulted in higher photocatalytic degradation efficiency. According to the findings, green SM-Zn NS can be used effectively in environmental remediation applications, as well as can effectively address the future medical concerns.

Ultrasound promoted synthesis of new azo fused dihydropyrano[2,3-c]pyrazole derivatives: In vitro antimicrobial, anticancer, DFT, in silico ADMET and Molecular docking studies.

A library of new azo fused dihydropyrano[2,3-c]pyrazole derivatives were synthesized via one pot four component reaction of ethyl acetoacetate, hydrazine hydrate, malononitrile and multifarious aryl azo-salicylaldehydes using catalyst-free, ultrasound irradiation approach. DFT calculations, for the synthesized molecules 5a-k were performed to gain insights of structural geometry and relevant quantum chemical parameters were predicted using B3LYP/6-311 (d,p) level of theory. Molecular docking studies of the synthesized compounds exhibit a good binding affinity towards the target of E. coli MurB and EGFR domains by forming various types of strong interactions with amino acids. Among them, 5h and 5i possess higher binding affinities of -12.7 and -11.7 kcal/mol towards E. coli MurB and EGFR domains. ADMET prediction reveals that, the synthesized compounds are having good pharmacokinetic profile. All the compounds were assessed for in vitro antimicrobial activity against human pathogenic bacterial and fungal strains, of which the compound 5h showed excellent MIC value of 0.19 μg/mL against B. cereus and the compounds 5a and 5c exhibited significant antifungal activity. Based on computational results, the selected compounds 5h and 5i were evaluated for anticancer activity against human cervical cancer cell line (HeLa) and live/dead cells was determined by AO/EtBr staining.

Bacillus licheniformis (MN900686) Mediated Synthesis, Characterization and Antimicrobial Potential of Silver Nanoparticles.

The use of bacteria in the synthesis of silver nanoparticles (AgNPs) emerges as an ecofriendly and exciting approach. In the present study, we reported the biosynthesis of AgNPs by using culture supernatant of the bacteria Bacillus licheniformis (MN900686). The biogenically synthesized AgNPs were confirmed by the change in the color of the culture filtrate from yellow to brown after the addition of AgNO3. Further characterization performed by means of UV vis-spectroscopy showed absorption peak at 414 nm which confirmed the formation of AgNPs. Fourier Transfer infrared (FTIR) confirmed the involvement of biological molecules in the formation of nanoparticles (NPs). The SEM revealed that the NPs have approximately 38 nm size. The agar well diffusion assay was used to determine antibacterial activity while tube dilution method was used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The human pathogenic bacterial strains i.e., P. aeruginosa (MN900691) and B. subtilis (MN900684), were used as test strains. The anti-bacterial assay against test strains revealed that these NPs showed concentration dependent increased zone of inhibition (ZOI). The maximum ZOI at 25 µL of AgNPs was 20 mm against B. subtilis after 24 hours of incubation. One-way ANOVA test showed significant ZOI (p ≤ 0.05) against B. subtilis. The MIC was ranged from 4.3-6.6 μg/mL while MBC ranged from 8.3 to 6.6 μg/mL. Overall, this study suggested that the biogenically synthesized NPs are an effective alternative source of antimicrobials against pathogenic bacteria.

Molecular docking and antimicrobial analyses of synthesized imidazole derivatives in solvent less condition, adjacent to human pathogenic bacterial strains

In the present study, we have been achieved effortless, highly adaptable multi-component synthesis of several biologically active imidazoles derivatives in single pot three components via means of the reaction of ammonium acetate, substituted aldehydes and benzyl using tartaric acid as an effective, highly efficient organocatalyst. The synthesis of all the compounds has been confirmed through elemental analysis, FTIR, 1HNMR, and 13C NMR. All of the produced imidazole derivatives were docked against a bacterial protein [glucosamine-6-phosphate synthase (GlcN-6-P)] which were obtained as of [RCSB protein data bank (PDB ID: 2VF5)] using Autodock-vina and obtained conformations of ligand complexes and proteins (PDB ID: 2VF5) were examined for binding energy and interactions of the docked arrangement via [Molegro Molecular Viewer 2.5 and Ligplot v.1.4.5]. The synthesized compounds were also checked for antimicrobial activities beside human pathogenic bacterial strains “Escherichia coli, Bacillus subtilis, Salmonella typhi, and Pseudomonas aeruginosa”by disk diffusion method by gentamicine reference and a negative control “DMSO”. Some of the Imidazole derivatives were found to have high antibacterial action against “Escherichia coli, Salmonella typhi, Bacillus subtilis”, and moderate activity against “Pseudomonas aeruginosa”.

Antibacterial activity of the micro and nanostructures of the optical material tris(8-hydroxyquinoline)aluminum and its application as an antimicrobial coating.

Although tris(8-hydroxyquinoline)aluminum (Alq3), a fluorescent optical organometallic material, is known for its applications in optoelectronics, it has only few and limited applications in the biological field. In this study, the antibacterial activity of Alq3 micro and nanostructures was investigated. We prepared Alq3 nanostructures. We prepared nanosized Alq3 as rice-like structures that assembled into flower shapes with an α-crystal phase. Then, Alq3 micro and nanostructure antibacterial activities were estimated against seven human pathogenic bacterial strains. Besides, we compared their antibacterial activities with those of standard antibiotics. The minimal inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and IC50 were evaluated. Alq3 micro and nanostructure antibacterial activity showed considerable values compared to standard antibiotics. Besides, the obtained data revealed that the antibacterial activity of Alq3 in nanostructures with a new morphology is more than that in microstructures. The antibacterial activity of Alq3 nanostructures was attributed to their more surface interactions with the bacterial cell wall. The molecules of 8-hydroxyquinoline in the Alq3 structure could play crucial roles in its antibacterial activity. To apply the achieved results, Alq3 was incorporated with polystyrene (PS) in a ratio of 2% to fabricate a PS/Alq3 composite and used to coat glass beakers, which showed inhibition in the bacterial growth reduced to 65% compared with non-coated beakers. The finding of this study showed that Alq3 could be used as a promising antimicrobial coating.