scholarly journals Synthesis, Characterization and Antimicrobial Activity of some New Dihydropyrano[c] Chromenes

Author(s):  
Ankita A. Bhalu ◽  
Pooja Moteriya ◽  
Sumitra Chanda ◽  
Shipra H. Baluja

Some new dihydropyrano[c]chromenes derivatives are synthesized from 4-hydroxycoumarin. The structure of newly synthesized compounds was confirmed by mass, 1H NMR and IR spectroscopy. Further, antimicrobial screening of these synthesized compounds was done against some bacterial (Gram positive as well as Gram negative) and fungal strains in N,N-dimethylformamide. It is observed that some of synthesized compounds exhibited significant antibacterial activity against Gram positive bacterial strains. The selected fungal strains were most resistant for the studied compounds as none of the synthesized compounds showed activity against any of the fungal strain studied. The best antibacterial activity was shown by ABR-10.

2011 ◽  
Vol 65 (1) ◽  
Author(s):  
Carmen Limban ◽  
Alexandru Missir ◽  
Ileana Chirita ◽  
George Nitulescu ◽  
Miron Caproiu ◽  
...  

AbstractNew acylthiourea derivatives, 2-((4-ethylphenoxy)methyl)-N-(phenylcarbamothioyl)benzamides, were tested by qualitative and quantitative methods on various bacterial and fungal strains and proved to be active at low concentrations against Gram-positive and Gram-negative bacteria as well as fungi. These compounds were prepared by the reaction of 2-((4-ethylphenoxy)methyl)benzoyl isothiocyanate with various primary aromatic amines, and were characterised by melting point and solubility. The structures were identified by elemental analysis, 1H and 13C NMR, and IR spectral data. The level of antimicrobial activity of the new 2-((4-ethylphenoxy)methyl)benzoylthiourea derivatives was dependent on the type, number and position of the substituent on the phenyl group attached to thiourea nitrogen. The iodine and nitro substituents favoured the antimicrobial activity against the Gram-negative bacterial strains, while the highest inhibitory effect against Gram-positive and fungal strains was exhibited by compounds with electron-donating substituents such as the methyl and ethyl groups.


2019 ◽  
Vol 70 (6) ◽  
pp. 1996-1999
Author(s):  
Catalin Araniciu ◽  
Smaranda Dafina Oniga ◽  
Cristina Ioana Stoica ◽  
Mariana Carmen Chifiriuc ◽  
Marcela Popa ◽  
...  

Considering the promising antimicrobial activity of compounds bearing the thiazole or the oxadiazole rings in their structures, we set out to obtain new antimicrobial molecules bearing the 2-(thiazol-5-yl)-1,3,4-oxadiazole schaffold. The structures of the 8 new compounds obtained was confirmed by physicochemical characterization including: 1H-NMR, MS and elemental analysis. Antimicrobial activity was investigated against 5 Gram-positive bacterial strains, 2 Gram-negative bacterial strains and 2 fungal strains. The newly synthesized compounds showed modest antimicrobial activity.


2009 ◽  
Vol 4 (12) ◽  
pp. 1934578X0900401 ◽  
Author(s):  
Luisa Pistelli ◽  
Alessandra Bertoli ◽  
Cecilia Noccioli ◽  
Jeanette Mendez ◽  
Rosa Anna Musmanno ◽  
...  

The EtOAc and n-BuOH extracts of Inga fendleriana inhibited Gram-positive, but not Gram-negative bacteria; a narrow spectrum of activity against Staphylococcus epidermidis was detected. The MIC values of the extracts ranged from 125 to 850 μg/mL. Quercetin 3-methylether, myricetin 3-O-rhamnoside and tricetin showed antibacterial activity against the same bacterial strains with MICs in the range from 31 to 250 μg/mL. In time-kill kinetic studies, the flavonoids showed bactericidal effects at the concentrations corresponding to four times the MICs.


Author(s):  
Shipra Baluja ◽  
Sumitra Chanda ◽  
Paras Ramavat

A series of oxadiazole derivatives were synthesized and were characterized by IR, 1H NMR and mass spectroscopy. All these synthesized compounds were tested for in vitro antimicrobial against four Gram positive bacteria, four Gram negative bacteria and four fungal strains in DMSO and DMF.


Author(s):  
Nirav M. Shah ◽  
Hitendra S. Joshi

Some new pyrimido[1,2-a]benzimidazole derivatives were synthesized by reacting 2-amino benzimidazole and chalcones in n-butanol at reflux temperature. In our present study we have used various heterocyclic chalcones derived from furfural and substituted acetophenones. All synthesized compounds were characterized by IR, 1H NMR and Mass spectroscopy. All synthesized compounds were screened for their antimicrobial activity against gram positive and gram negative bacteria which showed moderate to good activity.


2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Helmoz R. Appelt ◽  
Julieta S. Oliveira ◽  
Roberto C. V. Santos ◽  
Oscar E. D. Rodrigues ◽  
Maura Z. Santos ◽  
...  

A series of D-glucosamine derivatives were synthesized (2–4) and evaluated for their antimicrobial activity. Some of the compounds investigated have shown significant antimicrobial activity against Gram-positive and Gram-negative bacterial strains as well as a few fungal strains. The results suggest that the presence of sugar moiety is necessary to biological activity.


Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.


2020 ◽  
Author(s):  
Nusrat Abedin ◽  
Abdullah Hamed A Alshehri ◽  
Ali M A Almughrbi ◽  
Olivia Moore ◽  
Sheikh Alyza ◽  
...  

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.


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Hessa H. Al-Rasheed ◽  
Monirah Al Alshaikh ◽  
Jamal M. Khaled ◽  
Naiyf S. Alharbi ◽  
Ayman El-Faham

Novel series of 4,6-disubstituted-1,3,5-triazines containing hydrazone derivatives were synthesized employing ultrasonic irradiation and conventional heating. The ultrasonication gave the target products in higher yields and purity in shorter reaction time compared with the conventional method. IR, NMR (H 1 and C 13), elemental analysis, and LC-MS confirmed the structures of the new products. The antimicrobial and antifungal activities were evaluated for all the prepared compounds against some selected Gram-positive and Gram-negative bacterial strains. The results showed that only two compounds 7i (pyridine derivative) and 7k (4-chlorobenzaldehyde derivative) displayed biological activity against some Gram-positive and Gram-negative bacteria, while the rest of the tested compounds did not display any antifungal activity.


2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Shiara Ramdath ◽  
John Mellem ◽  
Londiwe Simphiwe Mbatha

Health issues involving inadequate treatment of diseases such as cancer and microbial infections continue to be the subject of much ongoing recent research. Biosynthesized silver nanoparticles (AgNPs) were characterized using Transmission Electron Microscopy (TEM), Zeta Sizer, Ultraviolet (UV), and Fourier Transform Infrared (FTIR) spectroscopy. Their antimicrobial activity was evaluated on selected Gram-positive and Gram-negative bacterial strains, using the disc diffusion and broth dilution assays. Cell viability profiles were evaluated using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) and apoptosis studies on selected human noncancer and cancer cells. The biosynthesized AgNPs were evaluated to be spherical clusters, with sizes between 40 and 70 nm. The absorption peak at 423 nm and the presence of polyphenols confirmed the synthesis and stabilization of these tested AgNPs. The AgNPs showed a good stability of −23.9 ± 1.02 mV. Good antimicrobial activity (6.0–18.0 mm) was seen on all tested bacteria at a minimum inhibitory concentration (MIC) ranging from 5 to 16 μg/ml, with the highest activity seen against Gram-negative Escherichia coli (18 ± 0.5 mm), and the lowest activity was seen against Gram-positive Listeria monocytogenes (6.0 ± 0.4 mm) after treatment with the AgNPs. These NPs showed a concentration-dependent and cell-specific cytotoxicity with low IC50 values (41.7, 56.3, and 63.8 μg/ml). The NPs were well tolerated by tested cells as indicated by a more than 50% cell viability at the high dose tested and low apoptotic indices (<0.2). These findings indicated that these biosynthesized AgNPs showed great potential as effective antibacterial agents and anticancer drug delivery modalities.


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