scholarly journals Synthesis and Antimicrobial Activities of Some New Heterocyclic Compounds Based on 6-Chloropyridazine-3(2H)-thione

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Nasser M. Abd El-Salam ◽  
Mohamed S. Mostafa ◽  
Gamal A. Ahmed ◽  
Othman Y. Alothman
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Antimicrobial Activities ◽  
Ring System ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative

Three tricyclic ring system, pyridazino[6,1-b]quinazolin-10-ones, benzimidazolo-pyridazine thione, and 1,2,4-benzotriazino-pyridazinethione along with imidazo-[1,2-b]-pyridazinethione, 1,2,4-triazolo[4,3-b]pyridazine-thione derivatives were synthesized starting from 6-chloropyridazin3-(2H)-thione. Some disulfide and sulfide derivatives were also prepared. The antimicrobial activity of the synthesized compounds was tested. Some of these compounds possess a highly response against gram-positive and gram-negative bacteria as well as fungi.

scholarly journals Antimicrobial Activity of Lignin and Lignin-Derived Cellulose and Chitosan Composites Against Selected Pathogenic and Spoilage Microorganisms

Polymers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 670 ◽  
Author(s):  
Alzagameem ◽  
Klein ◽  
Bergs ◽  
Do ◽  
Korte ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Low Temperatures ◽  
Food Packaging ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Scavenging Activity ◽  
Gram Positive ◽  
Gram Negative ◽  
Spoilage Bacteria ◽  
Chitosan Films

The antiradical and antimicrobial activity of lignin and lignin-based films are both of great interest for applications such as food packaging additives. The polyphenolic structure of lignin in addition to the presence of O-containing functional groups is potentially responsible for these activities. This study used DPPH assays to discuss the antiradical activity of HPMC/lignin and HPMC/lignin/chitosan films. The scavenging activity (SA) of both binary (HPMC/lignin) and ternary (HPMC/lignin/chitosan) systems was affected by the percentage of the added lignin: the 5% addition showed the highest activity and the 30% addition had the lowest. Both scavenging activity and antimicrobial activity are dependent on the biomass source showing the following trend: organosolv of softwood > kraft of softwood > organosolv of grass. Testing the antimicrobial activities of lignins and lignin-containing films showed high antimicrobial activities against Gram-positive and Gram-negative bacteria at 35 °C and at low temperatures (0–7 °C). Purification of kraft lignin has a negative effect on the antimicrobial activity while storage has positive effect. The lignin release in the produced films affected the activity positively and the chitosan addition enhances the activity even more for both Gram-positive and Gram-negative bacteria. Testing the films against spoilage bacteria that grow at low temperatures revealed the activity of the 30% addition on HPMC/L1 film against both B. thermosphacta and P. fluorescens while L5 was active only against B. thermosphacta. In HPMC/lignin/chitosan films, the 5% addition exhibited activity against both B. thermosphacta and P. fluorescens.

scholarly journals Hybrid Approach for Synthesis and Antimicrobial Activity of Heterocyclic Compounds

2018 ◽  
Vol 77 ◽  
pp. 35-52 ◽  
Author(s):  
Nisheeth C. Desai ◽  
Darshita V. Vaja
Keyword(s):  
Antimicrobial Activity ◽  
Heterocyclic Compounds ◽  
Hybrid Approach ◽  
Spectroscopic Techniques ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
E Coli ◽  
Microbial Strains

We have synthesized novel series of N-(1-(2-(1-phenyl-3-(p-tolyl)-1H-pyrazol-4-yl)-5-(pyridin-4-yl)-1,3,4-oxadiazol-3(2H)-yl)ethylidene)arylaniline and their derivatives. The structures of synthesized compounds were well characterized by spectroscopic techniques. Antimicrobial activity of the newly synthesized derivatives was evaluated against gram positive (S. aureus and S. pyogenes), gram negative bacteria (E. coli and P. aeruginosa), and strains of fungi (C. albicans, A. niger and A. clavatus). Among the screened derivatives 5c, 5f, 5i, 5l and 5t demonstrated superior antimicrobial activity against microbial strains.

scholarly journals Lipid Segregation Explains Selective Toxicity of a Series of Fragments Derived from the Human Cathelicidin LL-37

2009 ◽  
Vol 53 (9) ◽  
pp. 3705-3714 ◽  
Author(s):  
Raquel F. Epand ◽  
Guangshun Wang ◽  
Bob Berno ◽  
Richard M. Epand
Keyword(s):  
Antimicrobial Activity ◽  
Bacterial Species ◽  
Antimicrobial Activities ◽  
Gram Negative Bacteria ◽  
Selective Toxicity ◽  
Gram Positive ◽  
Gram Negative ◽  
Cytoplasmic Membranes ◽  
Anionic Lipids ◽  
Active Segment

ABSTRACT The only human cathelicidin, the 37-residue peptide LL-37, exhibits antimicrobial activity against both gram-positive and gram-negative bacteria. We studied the ability of several fragments of LL-37, exhibiting different antimicrobial activities, to interact with membranes whose compositions mimic the cytoplasmic membranes of gram-positive or of gram-negative bacteria. These fragments are as follows: KR-12, the smallest active segment of LL-37, with the sequence KRIVQRIKDFLR, which exhibits antimicrobial activity only against gram-negative bacteria; a slightly smaller peptide, RI-10, missing the two cationic residues at the N and C termini of KR-12, which has been shown not to have any antimicrobial activity; a longer peptide, GF-17, which shows antimicrobial activity against gram-positive as well as gram-negative bacteria; and GF-17D3, with 3 d-amino-acid residues, which is also selective only for gram-negative bacteria. Those fragments with the capacity to cluster anionic lipids away from zwitterionic lipids in a membrane exhibit selective toxicity toward bacteria containing zwitterionic as well as anionic lipids in their cytoplasmic membranes but not toward bacteria with only anionic lipids. This finding allows for the prediction of the bacterial-species selectivity of certain agents and paves the way for designing new antimicrobials targeted specifically toward gram-negative bacteria.

Antimicrobial activities of Antarctic sponges

1992 ◽  
Vol 4 (2) ◽  
pp. 179-183 ◽  
Author(s):  
J.B. McClintock ◽  
J.J. Gauthier
Keyword(s):  
Antimicrobial Activity ◽  
Growth Inhibition ◽  
Antimicrobial Activities ◽  
Marine Sponges ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Strong Activity ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Antarctic Marine

Methanol-toluene extracts of 17 common Antarctic marine sponges collected from shallow waters in McMurdo Sound in October–December 1989 were tested for suppression of growth of bacteria (gram-positive and negative), yeasts and fungi. Weak to moderate levels of antimicrobial activity occurred in all sponges. Antimicrobial activity was more common when gram-negative bacteria were exposed to sponge extracts; 47% of the sponge extracts caused growth inhibition in one or more gram-positive bacteria, while 100% of the extracts caused growth inhibition in gram-negative bacteria. Particularly strong activity was observed against two species of gram-positive bacteria exposed to extracts of the sponge Latrunculia apicalis and against one strain of gram-negative bacterium exposed to extracts of the sponge Haliclona sp. Antimicrobial responses against yeasts and fungi were generally non-existent or weak, with the exception of the yeast Candida tropicalis, which was strongly inhibited by extracts of the sponges Homaxonella balfourensis, Dendrilla membranosa, Kirkpatrickia variolosa, Gellius benedeni, Cinachyra antarctica and Scolymastia joubinia. Antimicrobial activity in these polar sponges is widespread but generally weaker than that found in temperate and tropical sponges.

Antimicrobial Activity of Iron-Halide Complexes Against Gram-Positive and Gram-Negative Bacteria

2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Antimicrobial Resistance ◽  
Extracellular Dna ◽  
Antibiofilm Activity ◽  
Gram Negative Bacteria ◽  
Bacterial Strains ◽  
Gram Positive ◽  
Gram Negative ◽  
Antimicrobial Substances ◽  
Mammalian Cell Lines

Antimicrobial resistance (AMR) has become one of the more serious threats to the global health. The emergence of bacteria resistant to antimicrobial substances decreases the potencies of current antibiotics. Consequently, there is an urgent and growing need for the developing of new classes of antibiotics. Three prepared novel iron complexes have a broad-spectrum antimicrobial activity with minimum bactericidal concentration (MBC) values ranging from 3.5 to 10 mM and 3.5 to 40 mM against Gram-positive and Gram-negative bacteria with antimicrobial resistance phenotype, respectively. Time-kill studies and quantification of the extracellular DNA confirmed the bacteriolytic mode of action of the iron-halide compounds. Additionally, the novel complexes showed significant antibiofilm activity against the tested pathogenic bacterial strains at concentrations lower than the MBC. The cytotoxic effect of the complexes on different mammalian cell lines show sub-cytotoxic values at concentrations lower than the minimum bactericidal concentrations.

scholarly journals Rational Design of Ag/ZnO Hybrid Nanoparticles on Sericin/Agarose Composite Film for Enhanced Antimicrobial Applications

2020 ◽  
Vol 22 (1) ◽  
pp. 105
Author(s):  
Wanting Li ◽  
Zixuan Huang ◽  
Rui Cai ◽  
Wan Yang ◽  
Huawei He ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Antimicrobial Activity ◽  
Composite Film ◽  
Water Absorption ◽  
Rational Design ◽  
Hybrid Nanoparticles ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
X Ray

Silver-based hybrid nanomaterials are receiving increasing attention as potential alternatives for traditional antimicrobial agents. Here, we proposed a simple and eco-friendly strategy to efficiently assemble zinc oxide nanoparticles (ZnO) and silver nanoparticles (AgNPs) on sericin-agarose composite film to impart superior antimicrobial activity. Based on a layer-by-layer self-assembly strategy, AgNPs and ZnO were immobilized on sericin-agarose films using the adhesion property of polydopamine. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray powder diffraction spectroscopy were used to show the morphology of AgNPs and ZnO on the surface of the composite film and analyze the composition and structure of AgNPs and ZnO, respectively. Water contact angle, swelling ratio, and mechanical property were determined to characterize the hydrophilicity, water absorption ability, and mechanical properties of the composite films. In addition, the antibacterial activity of the composite film was evaluated against Gram-positive and Gram-negative bacteria. The results showed that the composite film not only has desirable hydrophilicity, high water absorption ability, and favorable mechanical properties but also exhibits excellent antimicrobial activity against both Gram-positive and Gram-negative bacteria. It has shown great potential as a novel antimicrobial biomaterial for wound dressing, artificial skin, and tissue engineering.

scholarly journals Enaminone-Derived Pyrazoles with Antimicrobial Activity

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Mashooq Ahmad Bhat ◽  
Mohamed A. Al-Omar ◽  
Ahmed M. Naglah ◽  
Abdul Arif Khan
Keyword(s):  
Antimicrobial Activity ◽  
Gram Negative Bacteria ◽  
Significant Activity ◽  
Disc Diffusion ◽  
Initial Screening ◽  
Gram Positive ◽  
Gram Negative ◽  
Disc Diffusion Assay ◽  
Gram Positive Bacteria ◽  
Diffusion Assay

A series of pyrazoles derived from the substituted enaminones were synthesized and were evaluated for antimicrobial activity. All the compounds were characterized by the spectral data and elemental analysis. The synthesized compounds were initially screened for their antimicrobial activity against ATCC 6538, NCTC 10400, NCTC 10418, and ATCC 27853. During initial screening, compounds (P1, P6, and P11) presented significant antimicrobial activity through disc diffusion assay. These compounds were further evaluated for antimicrobial activity at different time points against Gram-positive and Gram-negative bacteria and presented significant activity for 6 hours. The activity was found to be greater against Gram-positive bacteria. In contrast at 24 hours, the activity was found only against Gram-positive bacteria except compound (P11), showing activity against both types of bacteria. Compound (P11) was found to have highest activity against both Gram-positive and Gram-negative bacteria.

Antimicrobial activity of Pycnarrhena cauliflora (Miers.) Diels. methanol extract

2021 ◽  
Vol 2 (2) ◽  
Author(s):  
Eti Nurwening Sholikhah ◽  
Maulina Diah ◽  
Mustofa ◽  
Masriani ◽  
Susi Iravati ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Methanolic Extract ◽  
Biological Activities ◽  
Positive Control ◽  
Diffusion Method ◽  
Gram Negative Bacteria ◽  
Gram Positive ◽  
Gram Negative ◽  
Gram Positive Bacteria ◽  
Methanolic Extracts

Pycnarrhena cauliflora (Miers.) Diels., local name sengkubak, is one of indigenous plants from West Kalimantan that has been used as natural flavor. Pycnorrhena cauliflora is one of species of Menispermaceae family which is rich in bisbenzylisoquinoline alkaloids. This alkaloids are known to have various biological activities including antiprotozoal, antiplasmodial, antifungal and antibacterial activities. This study aimed to investigate antimicrobial activity of  the P. cauliflora (Miers.) Diels. methanolic extracts against gram-positive and gram-negative bacteria. The methanolic extract of P. cauliflora (Miers.) Diels., root, leaf and stem were prepared by maceration. The disk-diffusion method was then used to determine the antimicrobial activity of the extracts against Streptococcus pyogenes, S. mutants, Staphylococcus aureus, S. epidermidis, Salmonella typhi, Shigella flexneri, Pseudomonas aeruginosa and Escherichia coli after 18-24 h incubation at 37 oC. Amoxicillin was used as positive control for gram-positive bacteria and ciprofloxacin was used as gram-negative bacteria. The inhibition zones were then measured in mm. Analysis were conducted in duplicates. The results showed in general the methanolic extracts of P. cauliflora (Miers.) Diels. root (inhibition zone diameter= 10-23 mm) were more active than that leaf (0-15 mm) and stem (0-17 mm) extracts against gram-positive bacteria. The zone inhibition diameter of amoxicillin as positive control was 8-42 mm. In addition, the methanolic extracts of P. cauliflora (Miers.) Diels. root (12-17 mm) were also more active than that leaf (0-12 mm) and stem (0-12 mm) extracts against gram-negative bacteria. The zone inhibition diameter of ciprofloxacin as positive control was 33-36 mm. In conclusion, the methanolic extract of P. caulifloria (Miers.) Diels. root is the most extract active against both gram-positive and gram-negative bacteria. Further study will be focused to isolate active compounds in the methanolic extract of the root.

scholarly journals Synthesis of New Furothiazolo Pyrimido Quinazolinones from Visnagenone or Khellinone and Antimicrobial Activity

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2793 ◽  
Author(s):  
Ameen Abu-Hashem
Keyword(s):  
Antimicrobial Activity ◽  
Growth Inhibition ◽  
Spectral Data ◽  
Elemental Analysis ◽  
13C Nmr ◽  
Heterocyclic Compounds ◽  
Gram Negative Bacteria ◽  
Gram Negative ◽  
Bacteria And Fungi ◽  
New Compounds

Substituted-6-methyl-1-thioxo-1,2-dihydro-3H-furo[3,2-g]pyrimido[1,6-a]quinazolin-3-ones (5a,b) were synthesized from condensation of visnagenone (2a) or khellinone (2b) with 6-amino-thiouracil (3) in dimethylformamide or refluxing of (4a) or (4b) in dimethylformamide. Hence, compounds (5a,b) were used as the starting materials for preparing many new heterocyclic compounds such as; furo[3,2-g]pyrimido[1,6-a]quinazoline (6a,b), furo[3,2-g]thiazolo[2′,3′:2,3]pyrimido[1,6-a]quinazolinone (7a,b), substituted-benzylidene-furo[3,2-g]thiazolo[2′,3′:2,3]pyrimido[1,6-a]quinazoline-3,5-dione (8a–f), 3-oxo-furo[3,2-g]pyrimido[1,6-a]quinazoline-pentane-2,4-dione (9a,b), 1-(pyrazole)-furo[3,2-g]pyrimido[1,6-a]quinazolinone (10a,b), 2-(oxo or thioxo)-pyrimidine-furo[3,2-g]pyrimido[1,6-a]quinazolinone (11a–d), 1-(methylthio)-furo[3,2-g]pyrimido[1,6-a]quinazolinone (12a,b), 1-(methyl-sulfonyl)-furo[3,2-g]pyrimido[1,6-a]quinazolinone (13a,b) and 6-methyl-1-((piperazine) or morpholino)-3H-furo[3,2-g]pyrimido[1,6-a]quinazolin-3-one (14a–d). The structures of the prepared compounds were elucidated on the basis of spectral data (IR, 1H-NMR, 13C-NMR, MS) and elemental analysis. Antimicrobial activity was evaluated for the synthesized compounds against Gram-positive, Gram-negative bacteria and fungi. The new compounds, furothiazolo pyrimido quinazolines 8a–f and 11a–d displayed results excellent for growth inhibition of bacteria and fungi.

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