Synthesis and Antimicrobial Screening of Some Novel 5-Substituted-1,10b-dihydroimidazole[1,2-c]quinazoline Derivatives

Author(s):  
Haribhai Rabari ◽  
Hetal Vankar ◽  
Beenkumar Prajapati

The emergence of multidrug microbial resistance is the main challenges that the modern scientists have so far been facing in the recent era. In this respect, new series of drug classes having potential to give antimicrobial effect have been synthesized. A new series of 5- substituted-1,10 b-dihydroimidazole[1,2-c]quinazoline derivatives 8a-e have been synthesized and screened for antibacterial activity and antifungal activity. Synthesized derivatives were characterized by IR, MASS and 1H-NMR spectroscopy. Synthesized compounds show good activity, which was comparable to the standard drug and it can be useful for the further clinical study. Antibacterial activity was evaluated against four different pathogenic bacterial strains like Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudo-monas aeruginosa. Among the screened compounds, 8e show good antibacterial activity against Staphylococcus aureus and Escherichia coli with MIC of 50 and 100 μg/ml respectively. Antifungal activity was evaluated  against two strains of fungi. Among the synthesized derivates, compound 8c was emerged out as the potent antifungal compound against Candida albicans and Aspergillus niger with MIC of 25 μg/ml and 75μg/ml respectively. Compound 8e also shows good antifungal activity with MIC of 50 μg/ml against both Candida albicans and Aspergillus niger. The overall results of this study indicated that  synthesized quinazoline derivatives had the potential to act as an antibacterial and antifungal agent, hence further investigation is warranted.

2020 ◽  
Vol 15 (6) ◽  
pp. 665-679
Author(s):  
Alok K. Srivastava ◽  
Lokesh K. Pandey

Background: [1, 3, 4]oxadiazolenone core containing chalcones and nucleosides were synthesized by Claisen-Schmidt condensation of a variety of benzaldehyde derivatives, obtained from oxidation of substituted 5-(3/6 substituted-4-Methylphenyl)-1, 3, 4-oxadiazole-2(3H)-one and various substituted acetophenone. The resultant chalcones were coupled with penta-O-acetylglucopyranose followed by deacetylation to get [1, 3, 4] oxadiazolenone core containing chalcones and nucleosides. Various analytical techniques viz IR, NMR, LC-MS and elemental analysis were used to confirm the structure of the synthesised compounds.The compounds were targeted against Bacillus subtilis, Staphylococcus aureus and Escherichia coli for antibacterial activity and Aspergillus flavus, Aspergillus niger and Fusarium oxysporum for antifungal activity. Methods: A mixture of Acid hydrazides (3.0 mmol) and N, Nʹ- carbonyl diimidazole (3.3 mmol) in 15 mL of dioxane was refluxed to afford substituted [1, 3, 4]-oxadiazole-2(3H)-one. The resulted [1, 3, 4]- oxadiazole-2(3H)-one (1.42 mmol) was oxidized with Chromyl chloride (1.5 mL) in 20 mL of carbon tetra chloride and condensed with acetophenones (1.42 mmol) to get chalcones 4. The equimolar ratio of obtained chalcones 4 and β -D-1,2,3,4,6- penta-O-acetylglucopyranose in presence of iodine was refluxed to get nucleosides 5. The [1, 3, 4] oxadiazolenone core containing chalcones 4 and nucleosides 5 were tested to determined minimum inhibitory concentration (MIC) value with the experimental procedure of Benson using disc-diffusion method. All compounds were tested at concentration of 5 mg/mL, 2.5 mg/mL, 1.25 mg/mL, 0.62 mg/mL, 0.31 mg/mL and 0.15 mg/mL for antifungal activity against three strains of pathogenic fungi Aspergillus flavus (A. flavus), Aspergillus niger (A. niger) and Fusarium oxysporum (F. oxysporum) and for antibacterial activity against Gram-negative bacterium: Escherichia coli (E. coli), and two Gram-positive bacteria: Staphylococcus aureus (S. aureus) and Bacillus subtilis(B. subtilis). Result: The chalcones 4 and nucleosides 5 were screened for antibacterial activity against E. coli, S. aureus and B. subtilis whereas antifungal activity against A. flavus, A. niger and F. oxysporum. Compounds 4a-t showed good antibacterial activity whereas compounds 5a-t containing glucose moiety showed better activity against fungi. The glucose moiety of compounds 5 helps to enter into the cell wall of fungi and control the cell growth. Conclusion: Chalcones 4 and nucleosides 5 incorporating [1, 3, 4] oxadiazolenone core were synthesized and characterized by various spectral techniques and elemental analysis. These compounds were evaluated for their antifungal activity against three fungi; viz. A. flavus, A. niger and F. oxysporum. In addition to this, synthesized compounds were evaluated for their antibacterial activity against gram negative bacteria E. Coli and gram positive bacteria S. aureus, B. subtilis. Compounds 4a-t showed good antibacterial activity whereas 5a-t showed better activity against fungi.


2002 ◽  
Vol 8 (5) ◽  
pp. 269-274 ◽  
Author(s):  
V. Zelenák ◽  
K. Györyová ◽  
D. Mlynarcík

The antibacterial and antifungal activity of zinc(II) carboxylates with composition Zn(RCOO)2•nH2O(R =H-, CH3− , CH3CH2CH2- , (CH3)2CH- , XCH2- , X=Cl, Br, I, n=0 or 2), [ZnX2(Nia+CH2COO-)2] (Nia=nicotinamide, X=Cl, Br, I) and [Zn(XCH2COO)2(Caf)2]•2H2O (Car=caffeine, X=Cl, Br) is studied against bacterial strains Staphylococcus aureus, Escherichia coli and yeast Candida albicans. The structural types are assigned to the prepared compounds and the influence of (i) carboxylate chain length, (ii) substitution of hydrogen atom of carboxylate by halogen and (iii) presence of N-donor organic ligands on the biological activity is discussed.


2019 ◽  
Author(s):  
Anup Masih ◽  
Jitendra Kumar Shrivastava ◽  
Hans Raj Bhat ◽  
Udaya Pratap Singh

Abstract The compounds were tested against panel of three Gram-positive, viz. Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and three Gram-negative bacterial strains viz. Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris for determination of their antibacterial efficacy using cefixime as a standard drug. The antibiofilm activities of the compounds were determined against Staphylococcus aureus, and Bacillus subtilis. The most potent compounds 7l amd 7m found bacteriostatic in time kill assay via inhibition of DNA Gyrase enzyme. The metabolic liability of compound 7m was determined using RS-Predictor and MetaPrint 2D React. The antifungal activity against human fungal pathogens was also estimated, where these compounds showed considerable activity in comparison to standard. The in vivo antibacterial activity of compound 7m was also determined using S. aureus induced murine infection model.


2021 ◽  
Vol 5 (4) ◽  
pp. 330-337
Author(s):  
Moses A. Guto Maobe ◽  
Leonard Gitu ◽  
Erastus Gatebe

The herbs Carissa spinarum, Physalis minima and Toddalia asiatica have traditionally been used in healing diabetes, malaria and pneumonia by the communities around the Kisii region, Kenya. However in the available literature, there is scanty information on effectiveness of different plant parts of the herbs in healing the ailments. The objective of this study was to investigate the potential antimicrobial and antifungal activity of methanolic extract of whole plant Physalis minima, leaf and root of Carissa spinarum and Toddalia asiatica against gram positive bacteria Staphylococcus aureus (ATCC 25923), gram negative bacteria Escherichia coli (ATCC 25922) and fungus Candida albicans (ATCC14053). Antibiotic disc methicillin, cotrimoxazole, chloramphenicol, gentamicin, ampicillin, nalidixic and nitrofurantoin were used in the study. In each herb, plant part was extracted by soaking in methanol/dichloromethane in ratio 1:1 for a week, filtered, concentrated by rotary vapor and cooled. The same process was repeated three times for all samples. The study was conducted by agar well diffusion method. Methanolic root extract of Toddalia asiatica showed highest antibacterial activity against Staphylococcus aureus (ATCC 25923), root extract of Carissa spinarum had highest antibacterial activity against Escherichia coli (ATCC 25922) while root extract of Toddalia asiatica showed highest antifungal activity. It was concluded that root extract of Toddalia asiatica showed highest antibacterial activity 16.7mm  against Staphylococcus aureus(ATCC 25923), root extract of Carissa spinarum had highest antibacterial activity 10 mm  against Escherichia coli (ATCC 25922)  while  root extract of Toddalia asiatica had highest antifungal activity 18 mm against Candida albicans.


2018 ◽  
Vol 17 (1) ◽  
pp. 28-38
Author(s):  
L. Sivasankerreddy ◽  
B. Nagamani ◽  
T. Rajkumar ◽  
M.S. Babu ◽  
N.Y. Subbaiah ◽  
...  

Background: Antibiotics play an important role in the treatment of infections to the humans and at the same time, irrational, frequent prescription of higher antibiotics, change in gene composition of microorganisms are all the reasons behind the development and introduction of new antibiotics against different microorganisms. Objective: In this project, an attempt has been made to synthesize some derivatives of diazenyl containing phenyl styryl ketones and also their in vitro screening was conducted against Mycobacterium tuberculosis, Escherichia coli, Klebsiella pneumonia, Bacillus subtilis, Staphylococcus aureus, Aspergillus niger and Candida albicans. Methods: Ten molecules were synthesized which are diazenyl containing chalcones. 4- aminoacetophenone was diazotised and piperidine was coupled with the formed diazonium chloride. Further, the acetoxy group underwent Claisen-Schmidt condensation with differently substituted aldehydes to form the final compounds- the chalcones. The proposed chemical structures were confirmed by different spectroscopic techniques like FTIR, 1H NMR and Mass spectroscopy. TLC was used to know that the reactants were exhausted and the formation of the product occurred. Sharp melting point of the compounds concludes the purity. Results: The MIC of the compounds 3CP, 3DP, 3EP and 3GP is 20 times the MIC of the standard fluconazole drug against Aspergillus niger. The compound 3GP is as equipotent as the standard drug Pyrazinamide with MIC of 3.12 µg/ml against Mycobacterium tuberculosis. Conclusion: The results are quite promising which on further studies may lead to drug molecules against different microorganisms. Especially, 3EP can be considered as a broad spectrum agent due to its potent activity against different microorganisms like Staphylococcus aureus, Escherichia coli, Klebsiella pneumonia and Candida albicans.


2019 ◽  
Vol 32 (1) ◽  
pp. 192-194
Author(s):  
S. Sudha Kumari

In present work, the screening of antimicrobial activities of copper(II) and cobalt(II) complexes with Schiff base ligand derived from the condensation of citral with valine (amino acid) was carried out on agar plates are reported. The antibacterial activity of Schiff base and its copper(II) and cobalt(II) complexes were evaluated against two bacterial strains Staphylococcus aureus (Gram-positive), Escherichia coli (Gram-negative) and fungus Candida albicans. The results revealed that the Schiff base ligand exhibited the poor antimicrobial activity against Escherichia coli and Candida albicans except for Staphylococcus aureus. Generally, Gram-negative bacteria shows rigid outer membrane, well enough to defend against the drug but Schiff base (citral with valine derived) impregnated cobalt(II) complex seem to be more active against Escherichia coli organisms in comparison to copper(II) complex, which exhibits higher activity than uncomplexed ligand. The antimicrobial results revealed that cobalt(II) and copper(II) complexes have a considerable antibacterial activity than antifungal activity and suggest their potential application as antibacterial agents.


2019 ◽  
Author(s):  
Anup Masih ◽  
Jitendra Kumar Shrivastava ◽  
Hans Raj Bhat ◽  
Udaya Pratap Singh

Abstract The compounds were tested against panel of three Gram-positive, viz. Staphylococcus aureus, Bacillus subtilis, Bacillus cereus and three Gram-negative bacterial strains viz. Pseudomonas aeruginosa, Escherichia coli, and Proteus vulgaris for determination of their antibacterial efficacy using cefixime as a standard drug. The antibiofilm activities of the compounds were determined against Staphylococcus aureus, and Bacillus subtilis. The most potent compounds 7l amd 7m found bacteriostatic in time kill assay via inhibition of DNA Gyrase enzyme. The metabolic liability of compound 7m was determined using RS-Predictor and MetaPrint 2D React. The antifungal activity against human fungal pathogens was also estimated, where these compounds showed considerable activity in comparison to standard. The in vivo antibacterial activity of compound 7m was also determined using S. aureus induced murine infection model.


2019 ◽  
Vol 70 (10) ◽  
pp. 3603-3610
Author(s):  
Madalina Mihalache ◽  
Cornelia Guran ◽  
Aurelia Meghea ◽  
Vasile Bercu ◽  
Ludmila Motelica ◽  
...  

The three copper complexes having a-ketoglutaric acid (H2A) and 1- (o-tolyl) biguanide (TB) ligands have been synthesized and characterized. The proposed formulas for these complexes are: [Cu(TB)(HA)]Cl (C1), [Cu(TB)(HA)CH3COO]�H2O (C2) and [Cu(TB)(HA)](NO3) (C3) where HA represents deprotonated H2A. The complexes obtained were tested for antibacterial activity against Staphylococcus aureus ATCC 25923 and Pseudomonas aeruginosa ATCC 27853, antifungal activity on Candida albicans ATCC 10231 and antitumor activity on HeLa tumor cells. Due to the antitumor, antifungal, antimicrobial activity and inhibition of inert substrate adhesion, complexes synthesized could be used for potential therapeutic applications.


2011 ◽  
Vol 8 (3) ◽  
pp. 1456-1461 ◽  
Author(s):  
Donatus Ebere Okwu ◽  
Fred Uchenna Nnamdi

Phenenthrene alkaloid identified as 1-ethanamino 7 hex-1-yne-5I-one phenanthrene was isolated from the ethanolic extract of the leaves ofBryophyllum pinnatum(syn. B. calcinum kalanchoe pinnata) a versatile Nigeria medicinal plant. The structure was elucidated using NMR, IR, UV and MS spectral data. Antimicrobial studies showed that the isolated compound successfully inhibitedPsuedomonas aeruginosa, Klebsiella pneumonia, Staphylococcus aureus, Escherichia coli, Candida albicansandAspergillus niger. This result authenticates the use ofbryophyllum pinantumin phytomedicine for disease prevention and treatment of infections.


2021 ◽  
Vol 5 (1) ◽  
pp. 1-9
Author(s):  
Antonio Carlos Pereira de Menezes Filho ◽  
Matheus Vinícius Abadia Ventura ◽  
Carlos Frederico de Souza Castro

Tibouchina granulosa is a species that blooms annually in several regions of Brazil. This species is still little explored in terms of phytocompounds in all organs of this plant, especially the floral organ. Flowers of T. granulosa were collected in the municipality of Rio Verde, Goiás, Brazil, in 2021. The hydroethanolic floral extract was prepared by maceration and qualitative phytochemical (colorimetric reactions and salt formation) and antibacterial analyzes performed and the results expressed in millimeters of inhibition at different concentrations in mg mL-1. Several phytochemical classes were observed with positive results, especially for alkaloids, phenolics, oxylates, saponins, carbohydrates and tannins. As for the bacterial assay, potential antibacterial activity was observed for all bacterial strains tested, except for Salmonella serovar Thyphymurium and serovar Enteritidis. Expressive inhibitions were observed for Enterococcus faecalis > Pseudomonas aeruginosa > Staphylococcus aureus and Escherichia coli at the highest concentrations between 100-50 mg mL-1. The floral extract of Tibouchina granulosa showed phytotherapeutic potential with the presence of several phytochemical groups and expressive antibacterial activity.


Sign in / Sign up

Export Citation Format

Share Document