scholarly journals Synthesis and Antibacterial Activities of Some Schiff Bases

2011 ◽  
Vol 8 (1) ◽  
pp. 212-216 ◽  
Author(s):  
Mohamed N. Ibrahim ◽  
Salaheddin A. I. Sharif ◽  
Ahmad N. EL-Tajory ◽  
Asma A. Elamari

Schiff basesp-hydroxybenzylidene-2-carboxyaniline,p-nitrobenz-ylidene-2-carboxyaniline,p-(N, N-dimethyl)aminobenzylidene-2-carboxyaniline,N-(4-hydroxybezylidene)-benzene-1,2-diamine,N--(4-nitrobezylidene)benzene-1,2-diamine,N-(4-(N, N-dimethylaminobezylidene)benzene-1,2-diamine,N-(4-(N,N-dimethylamino)benzylidene)naphthalen-1-amine,N-(4-nitrobenzylidene)naphthalen-1-amine,N--(4-chlorobenzylidene)naphthalen-1-amine,sodium-4-(4-(N,N-dimethyl amino)benzylideneamino)naphthalene-1-sulfonate,sodium -4-(4-nitrobenzylidene-amino)naphthalene-1-sulfonate and sodium-4-(4-chlorobenzylideneamino) naphthalene-1-sulfonate obtained by condensation of aniline and naphthyl-amine derivatives with some aromatic aldehydes were characterized by physical and spectral methods. The biological activity of these products were as antibacterial agents against three species of human pathogenic bacteria such asEscherichia coli, Staphylococcus aureusandKlebsiella sp. Nearly 50% of these compounds showed reasonable activity against the bacterial species investigated and we found that the antibacterial activity is dependent on the molecular structure of the compounds.

2011 ◽  
Vol 287-290 ◽  
pp. 1947-1951 ◽  
Author(s):  
Jing Xian Xu ◽  
Ye Ting Lin ◽  
Qiang Lin ◽  
Wen Yuan ◽  
Xue Qiong Yin ◽  
...  

Two Schiff bases of chitosan (CTS) were synthesized from 4-methoxylbenzylaldehyde (CH3O-CTS) and 4-methylbenzylaldehyde(CH3-CTS). The Schiff bases were characterized by FTIR, DSC-TGA, solid13C CP-Mas NMR, and elemental analysis. Antibacterial activities of the Schiff bases against Escherichia coli and Staphylococcus aureus were measured by the optical density method. The antibacterial activity of the Schiff bases is better than that of the original CTS. The IC50of CH3O-CTS and CH3-CTS againstEscherichia coliis respectively 40.3 ppm and 43 ppm, which being 38.5 ppm and 39.5 ppm against Staphylococcus aureus, lower than IC50of chitosan, being 59.5 ppm and 52 ppm againstEscherichia coliand Staphylococcus aureus, respectively.


Coumarin is a heterocyclic moiety containing benzo pyran ring structure. It is widely distributed in the plant kingdom as a glycoside. Many compounds of medicinal and pharmaceutical importance possess coumarin ring structure. Drugs with coumarin structure can be synthesized by many well-known synthetic reactions. Coumarin derivatives were found to be antibacterial, anticoagulant, antiinflammatory, anti-HIV, anti-cancer and antioxidant. As part of the search for new and effective antibacterial agents, eight novel derivatives of coumarins were synthesized by Mannich reaction. All the compounds were evaluated for antibacterial activity against Staphylococcus aureus and Escherichia coli using ciprofloxacin as standard and DMSO as solvent. Three of the synthesized derivatives exhibited good antibacterial activity against Staphylococcus aureus and Escherichia coli. The work must be extended so as to develop coumarin derivatives into highly effective antibacterial agents.


2001 ◽  
Vol 8 (2) ◽  
pp. 95-101 ◽  
Author(s):  
Zahid H. Chohan ◽  
Maimoon F. Jaffery ◽  
Claudiu T. Supuran

Schiff bases were obtained by condensation of 2-amino-l,3,4-thiadiazole with 5-substituted-salicylaldehydes which were further used to obtain complexes of the type [M(L)2]Cl2, where M=Co(II), Cu(II), Ni(II) or Zn(II). The new compounds described here have been characterized by physical, spectral and analytical data, and have been screened for antibacterial activity against several bacterial strains such as Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The antibacterial potency of these Schiff bases increased upon chelation/complexation, against the tested bacterial species, opening new aproaches in the fight against antibiotic resistant strains.


2016 ◽  
Vol 1 (3) ◽  
pp. 457-462 ◽  
Author(s):  
Md Nuruzzaman Munsi ◽  
Nathu Ram Sarker ◽  
Razia Khatun ◽  
Mohammed Khorshed Alam

Cow’s milk containing pathogenic bacteria is an important threat to the consumers. The objectives of the present study were to identify the bacterial agents of public health importance in milk samples (n=35) of different locations and to determine their sensitivity to different antibiotics. The milk samples were collected and transported aseptically and subsequently allowed for culture in bacteriological media, Gram’s staining and biochemical tests for the identification of bacterial species. The bacteria identified were Staphylococcus aureus, Escherichia coli and Salmonella typhi, and their prevalence, in case of vendor milk specimens (n=28), were 96.43%, 53.57% and 35.71% respectively, and of brand milk specimens (n=7), were 42.86 %, 28.57% and 0%, respectively. This suggests that cautionary measures should be taken for quality milk production and consumption. The antibiotic sensitivity test was done by disc diffusion method and the average inhibition zones, in case of Staphylococcus aureus, were 32 mm for oxytetracycline, 26 mm for amoxicillin, 35 mm for ciprofloxacin, 27 mm for cefotaxime, 30 mm for ceftriaxone, 30 mm for azithromycin, and 26 mm for erythromycin; in case of Escherichia coli, were 5 mm for oxytetracycline, 9 mm for amoxicillin, 22 mm for ciprofloxacin, 30 mm for cefotaxime, 31 mm for ceftriaxone, 15 mm for azithromycin, and 0 mm for erythromycin; in case of Salmonella typhi., were 25 mm for oxytetracycline, 24 mm for amoxicillin, 38 mm for ciprofloxacin, 31 mm for cefotaxime, 34 mm for ceftriaxone, 24 mm for azithromycin, and 0 mm for erythromycin. Therefore, ciprofloxacin and ceftriaxone may be the antibiotics of first choice, and cefotaxime and azithromycin may be the second choice among the test antibiotics for the treatment of illness caused by these bacteria.Asian J. Med. Biol. Res. December 2015, 1(3): 457-462


Author(s):  
Gouse Basha Sheik ◽  
Muazzam Sheriff Maqbul ◽  
Gokul Shankar S. ◽  
Ranjith M S

Objective: To isolate and characterize novel actinomycetes and to evaluate their antibacterial activity against drug-resistant pathogenic bacteriaMethods: In the present study, 19 soil samples were collected from different localities of Ad-Dawadmi, Saudi Arabia. Actinomycetes were isolated from these samples using serial dilution and plating method on Actinomycetes isolation agar supplemented with nalidixic acid and actidione to inhibit bacteria and fungi. Crude extracts of potential actinomycetes were produced by submerged fermentation. The antimicrobial activity of crude extracts of actinomycetes was tested against different bacteria using the agar well diffusion method. Characterization of the isolates was done by morphological, physiological and biochemical methods.Results: A total of 9 (47%) isolates of actinomycetes were isolated from 19 different soil samples tested. Among them, 4 (44%) isolates confirmed as Streptomyces sp. showed potential antimicrobial activity against one or more test organisms. Crude extracts were made from these 4 actinomycetes isolates(DOM1, DOM3, DP3, DP4)and tested for their antibacterial activities against 4 different clinical bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus). Crude extract from DP3 isolate showed highest antibacterial activity against all the four test organisms (28 mm, 21 mm, 20 mm and 18 mm) respectively and DP4 showed lowest antibacterial activity against all the four test organisms (14 mm, 12 mm, 0 mm, 6 mm) respectively. The highest zone of inhibition was shown by DP3 against Staphylococcus aureus (28 mm) and Escherichia coli was resistant for DP4. Most of the Inhibition zones produced by crude extracts showed significant differences when compared with control, tested against test organisms (P<0.05). Inhibition zones produced by DP3 and DOM1 against Staphylococcus aureus were 28 mm and 23 mm, respectively which were strong active when compared with control Ciprofloxacin (18 mm).Conclusion: Further studies for purification of bioactive metabolites and molecular characterization analysis of isolated Streptomyces sp. are in progress which would be helpful in discovering novel compounds of commercial value.


2018 ◽  
Vol 42 (10) ◽  
pp. 512-514
Author(s):  
Rui-bo Xu ◽  
Xiao-tian Yang ◽  
Hai-nan Li ◽  
Peng-cheng Zhao ◽  
Jiao-jiao Li ◽  
...  

Two new bis-Schiff bases containing a piperazine ring, N,N‘-bis(4-chlorobenzylidene)- and N,N‘-bis(4-cyanobenzylidene)-1,4-bis(3-aminopropyl)piperazine, were prepared by the reaction of N,N‘-bis(3-aminopropyl)piperazine with 4-chloro- and 4-cyanobenzaldehyde, respectively. The dichloro compound was fully identified by X-ray crystallography and it exhibited good antibacterial activity against Escherichia coli, Staphylococcus aureus and Bacillus subtilis.


2020 ◽  
Vol 15 (9) ◽  
pp. 1934578X2095325
Author(s):  
Bala Namata Abba ◽  
Abderrahmane Romane ◽  
Amadou Tidjani Ilagouma

Endostemon tereticaulis (poir.) M.Ashby is a species of the Lamiaceae family present in Niger. This plant is used in traditional medicine due to its various biological potentialities. The present study investigated the chemical composition of the essential oil and the antibacterial activity of the essential oil and ethanolic extract of Endostemon tereticaulis against resistant pathogenic bacteria. Gas chromatography-mass spectrometry analysis of the essential oil led to the identification of 43 compounds representing 99.55% of the total essential oil. The major components were caryophyllene oxide (15.17%) followed by α-humulene (13.96%), α-copaene (11.75%), ( E)-β-caryophyllene (8.44%), and δ-cadinene (6.78%). The antibacterial activity was tested against multiresistant Acinetobacter baumannii P1483, Salmonella spp. H1548, extended-spectrum β-lactamase- Escherichia coli Bu8566, Enterobacter cloacae Bu147, Proteus mirabilis Bu190 , Pseudomonas aeruginosa (ATCC 27853), Klebsiella pneumoniae (ATCC 700603), Escherichia coli (ATCC 25922), Enterococcus faecium H3434, methicillin-resistant Staphylococcus aureus P1123, and Staphylococcus aureus (ATCC 25923). The antibacterial assays revealed that the essential oil was more active than the ethanolic extract against the studied bacteria with minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values ranging from 0.06 to 2 mg/mL. Also, the ethanolic extract was effective against the bacteria tested with MIC and MBC values ranging from 0.12 to 3 mg/mL. This study showed that Endostemon tereticaulis essential oil is rich in bioactive compounds. Ethanolic extract and essential oil exhibited potential antibacterial activity. These results provide a scientific basis for the use of this plant in traditional medicine. The current study described for the first time the antibacterial activity of Endostemon tereticaulis.


2017 ◽  
Vol 23 (3) ◽  
pp. 197-203 ◽  
Author(s):  
Shaikha S. Alneyadi ◽  
Anas A. Abdulqader ◽  
Alaa A. Salem ◽  
Ibrahim M. Abdou

Abstract4-Trifluoromethylpyridine derivatives 4–8 represent good candidates for the discovery of new antibacterial agents. Fluorinated pyridine nucleosides 4–7 and non-nucleoside analogues 8a,b were synthesized and evaluated for their antibacterial activities against Staphylococcus aureus, Bacillus infantis, Escherichia coli and Stenotrophomonas maltophilia. The minimum inhibitory concentrations (MICs) of the new nucleosides 4–7 range from 1.3 to 4.9 μg/mL and MICs of fluoroaryl derivatives 8a,b are in the range of 1.8–5.5 μg/mL. Activity of amoxicillin, the reference drug, is 1.0–2.0 μg/mL under similar conditions.


Author(s):  
Shruti Tyagi

Objective: This study demonstates  a simple, cost effective protocol  for biosynthesis of stable silver (Ag) and gold (Au) nanoparticles from Hibiscus Rosa sinesis and their comparison by applying antibacterial activities against nine pathogenic bacterial species.Methods: Silver (Ag) and gold (Au) nanoparticles were biosynthesized from Hibiscus Rosa sinesis were characterized by UV–VIS spectroscopy, FTIR and TEM. The antibacterial activities  of AgNPs  and AuNPs were evaluated against  9 pathogenic bacterial species  Pseudomonas aeroginosa, Bacillus subtilis Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Enterobacter aerogens, Escherichia coli, Streptococcus pneumoniae, Aeromonas hydrophila by the agar disc diffusion method.Results: Synthesized AgNPs  were obtained in 13.01 to 28.14 nm size range, while AuNPs were in  6.32 to 18.19 nm size range. The results of Fourier transform infrared spectroscopy (FTIR) spectra indicates  that the AuNPs are bound to amine groups and the AgNPs to carboxylate ion groups. The antibacterial activities  of AgNPs,  the zone of inhibition significantly increased with the  increases of concentrations of AgNPs in all pathogenic bacterial species  except  in the case of S. epidermidis at 50%, S. aerogenes and A. hydrophila at 70%, while in case of AuNPs antibacterial activity  was displayed  only against B. subtilis at 20% and 100% concentration.Conclusion: This study suggests that AgNPs exhibits outstanding antibacterial activity against pathogenic bacteria as compared to AuNPs synthesized from Hibiscus Rosa sinensis leaf extract and insights to their potential applicability as an alternative antibacterial  agent in microbial and human health system to reduce the resistance ability of pathogenic bacteria. Keywords: silver nanoparticles; gold  nanoparticles; UV–VIS spectroscopy; FTIR; TEM; antibacterial activities.  


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