scholarly journals Synthesis, Characterization and Biological Properties of Tridentate NNO, NNS and NNN Donor Thiazole-Derived Furanyl, Thiophenyl and Pyrrolyl Schiff Bases and Their Co(II), Cu(II), Ni(II) and Zn(II) Metal Chelates

2000 ◽  
Vol 7 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Zahid H. Chohan ◽  
Samina Kausar

2-Aminothiazole undergoes condensation reactions with furane-, thiophene- and pyrrole-2-carboxylaldehyde to give tridentate NNO, NNS and NNN Schiff bases respectively. These tridentate Schiff bases formed complexes of the type [M (L)2]X2 where [M=Co(II), Cu(II), Ni(II) or Zn(II), L=N-(2-furanylmethylene)-2-aminothiazole (L1), N-(2-thiophenylmethylene)-2-aminothiazole (L2), N-(2-pyrrolylmethylene)-2-aminothiazole (L3) and X=Cl. The structures of these Schiff bases and of their complexes have been determined on the basis of their physical, analytical and spectral data. The screening results of these compounds indicated them to possess excellent antibacterial activity against tested pathogenic bacterial organisms e.g., Escherichia coli, Staphylococcus aureous and Pseudomonas aeruginosa. However, in comparison, their metal chelates have been shown to possess more antibacterial activity than the uncomplexed Schiff bases.

1999 ◽  
Vol 6 (2) ◽  
pp. 75-80 ◽  
Author(s):  
Zahid H. Chohan

A number of thiazole derived tridentate Schiff-bases (LH) and its metal chelates of the type [M(L)2X] where M=Ni(II), Cu(II) and Zn(II), L=substituted salicylaldehyde (5-H, 5-CH3, 5-OCH3, 5-NO2 and 5-Cl) and X=CI have been synthesized and characterized with the help of elemental analyses, conductivity measurements, magnetic moments, UV-Vis, IR and NMR spectral data. An octahedral structure for Ni(II) and Zn(II) and a distorted octahedral structure for Cu(II) chelates have been proposed. All the Schiff-bases and their metal chelates have been screened for their biological activity against Escherichia coli, Staphylococcus aureous , Pseudomonas aeruginosa and Klebsiella pneumonae and in comparison, the metal chelates have been shown to possess more antibacterial activity than the uncomplexed Schiff-bases.


1999 ◽  
Vol 6 (3) ◽  
pp. 149-152 ◽  
Author(s):  
Zahid H. Chohan ◽  
M. Praveen

A novel class of acetylferrocene-derived Schiff-bases such as 2-pyrazinoyl-1-(2-ferroceneylmethylene)- hydrazide (HL1) and 2-nicotinoyl-1-(2-ferrocenylmethylene)hydrazide (HL2) have been synthesized and characterized by their IR, H1 NMR, C13 NMR and microanalytical date. The biological effect induced due to the coupling of ferrocene molecule with the aroylhydrazines e.g., pyrazinoylhydrazine and nicotinoylhydrazine has been studied against bacterial species such as Escherichia coli, Pseudomonas aeruginosa , Staphylococcus aureus and Klebsiella pneumonae.


2018 ◽  
Vol 16 (S1) ◽  
pp. S155-S163 ◽  
Author(s):  
S. Mehalaine ◽  
O. Belfadel ◽  
T. Menasria ◽  
A. Messaili

The present study was carried out to determine, for the first time, the chemical composition and antibacterial activity of essential oils derived from the aerial parts of three aromatic plants Thymus algeriensis Boiss & Reut, Rosmarinus officinalis L., and Salvia officinalis L. growing under semiarid conditions. The essential oils were chemically analyzed and identified by gas chromatography (GC) and GC/ mass spectrometry (GC/MS) and their antimicrobial activity was individually evaluated against Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa using both agar disk diffusion and agar dilution methods. The major constituents of Thymus algeriensis essential oil were identified as camphor (13.62%), 1,8-cineol (6.00%), borneol (5.74%), viridiflorol (4.00%), and linalool (3.93%). For Rosmarinus officinalis essential oil, 48 compounds were characterized, of which the main constituents were camphor (17.09%), Z-β-ocimene (10.88%), isoborneol (9.68%), α-bisabolol (7.89%), and borneol (5.11%). While, Salvia officinalis essential oil was characterized by β-thujone (16.44%), followed by viridiflorol (10.93%), camphor (8.99%), 1,8-cineol (8.11%), trans-caryophyllene (5.85%), and α-humulene (4.69%) as the major components. Notably, results from antibacterial screening indicated that Thymus algeriensis and Salvia officinalis essential oils exhibited a strong inhibitory effect against both Escherichia coli and Staphylococcus aureus compared to Rosmarinus officinalis essential oil. Further, less activity was recorded against Pseudomonas aeruginosa for the three tested essential oils.


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.


2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Flávia Cíntia de Oliveira ◽  
Tamara Rezende Marques ◽  
Gustavo Henrique Andrade Machado ◽  
Thaís Cristina Lima de Carvalho ◽  
Aline Aparecida Caetano ◽  
...  

Abstract The phenolic compounds from various extracts of jabuticaba skin powder (JSP) were characterized in this study, and the antibacterial activity assessed. The phenolic compounds were extracted from the JSP using four methods: a) acetone extraction - 1 g JSP: 10 mL 70% acetone, resting for 2 hours; b) aqueous extract - 1 g JSP: 15 mL water, under agitation; c) ethanolic extract - 1 g JSP: 15 mL acidified ethanol, under agitation; and d) methanolic extract - 1 g JSP: 50 mL 50% methanol, under reflux. The antibacterial activity was evaluated by the agar diffusion assay, using Escherichia coli ATCC 11229, Salmonella choleraesuis ATCC 6539, Pseudomonas aeruginosa ATCC 15442, Staphylococcus aureus ATCC 6538 and Listeria monocytogenes ATCC 19117. The ethanolic and methanolic extracts showed the highest levels of phenolic compounds, especially of cyanidin chloride, catechin and epicatechin. The extracts did not inhibit the growth of Escherichia coli and Salmonella choleraesuis, but inhibited 30% of the growth of Pseudomonas aeruginosa with an extract concentration of 250 µg mL-1. Against Staphylococcus aureus and Listeria monocytogenes the highest inhibitory effect observed was 41.8% for the ethanolic extract, followed by 36% inhibition by the methanolic extract, thus revealing the potential of these extracts as possible alternatives for use in the food and/or pharmaceutical industries.


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.


Author(s):  
O B Oloyede

This study investigated phytochemical content, radical scavenging and antibacterial activities of aqueous extract of leaves of Jatropha curcas Linn. Quantitative phytochemical analyses of alkaloids, phenols, tannins and flavonoids contents were carried out; radical scavenging activity was assessed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical and hydrogen peroxide inhibition assays while Disc diffusion and Agar well (ditch) diffusion methods were used for antibacterial activity against Klebsiella pneumonia, Escherichia coli, Pseudomonas aeruginosa, Staphilococcus aureus and Proteus species at 62.5, 125, 250 and 500 mg/mL. The extract contained alkaloids (1.600± 0.58 %), tannins (0.121 ± 0.00 mg/mL), phenols (0.463 ± 0.06 mg/mL) and flavonoids (0.672 ± 0.00 mg/mL), and showed radical scavenging activities against DPPH (IC50 = 21.24) and hydrogen peroxide (15.67 mg/mL) which were less than that of Butylated hydroxyanisole (BHA); IC50 = 3.92 (DPPH) and 6.19 mg/mL (hydrogen peroxide) respectively. It also showed antibacterial activity against Klebsiella pneumonia, Escherichia coli, and Pseudomonas aeruginosa at 250 and 500 mg/ml (MIC = 125 mg/mL), which were resistant to ampicillin, chloxacillin and erythromycin, and the extract was inactive against Staphilococcus aureus and Proteus species at these concentrations, though all were sensitive to gentamycin. This shows that the aqueous extract of leaves of Jatropha curcas Linn may possess some of the folkloric properties claimed.


2018 ◽  
Vol 85 (0) ◽  
Author(s):  
Gabriela Silva Moura ◽  
Ivan Júnior de Oliveira ◽  
Lisandro Tomas da Silva Bonome ◽  
Gilmar Franzener

ABSTRACT: Natural products extracted from plants have always played an important role in the discovery of bioactive substances. This work carried out a review of the literature on the bioactive activities of Eugenia uniflora L. (Surinam cherries), as a potential plant in the various uses, be it medicinal, antimicrobial, antioxidant, insecticide and protective. In the literature, studies were found to confirm the antibacterial activity of E. uniflora leaves extract on Streptococcus, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli. The presence of antioxidant compounds as total phenolics, such as anthocyanins and flavonoids, induction in the protection of plants by phytoalexins, as well as insecticidal and anthelmintic effects by the use of the extract of the E. uniflora tree. Although these different potential biotics of E. uniflora have already been reported, further studies are still needed on the use of natural products extracted from E. uniflora for employment for different purposes.


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.


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