scholarly journals Clean Procedure and DFT Study for the Synthesis of 2-Amino-3-ethoxycarbonyl-4-(aryl)-4H-pyrano-[3,2-c]-chromene-5-ones Derivatives: A Novel Class of Potential Antimicrobial and Antioxidant Agents

2013 ◽  
Vol 2013 ◽  
pp. 1-9
Author(s):  
R. Medyouni ◽  
N. Hamdi ◽  
R. Ben Said ◽  
A. S. Al-Ayed ◽  
Fethi Zagrouba
Keyword(s):  
Antibacterial Activity ◽  
Nmr Spectra ◽  
Antioxidant Activities ◽  
Dft Study ◽  
New Class ◽  
Antioxidant Agents ◽  
Two Component ◽  
C Nmr

2-Amino-3-ethoxycarbonyl-4-(aryl)-4H-pyrano-[3,2-c]-chromene-5-ones5is synthesized by the two-component reaction of 4-hydroxycouamrin with ethyl-2-cyano-3-(aryl) acrylate3. The structures of the obtained compounds are confirmed by analytical IR,1H, and13C-NMR spectra to elucidate the different positions of protons and carbons and as well as theoretic studies (DFT/B3LYP). All the newly synthesized compounds are screened for their antibacterial. Furthermore, these compounds showed antioxidant activities of different extents with respect to individual compounds as well as to the antioxidant methods. The compounds5a–ewere found to be the most active antioxidant in the series then Trolox, which makes the investigated complexes a promising new class of antibacterial activity compounds.

scholarly journals Bioactivities of plant extracts collected in Halmahera, Indonesia: A bioprospection study of underexplored plant species

2021 ◽  
pp. 376-384
Author(s):  
Marlin Megalestin Raunsai ◽  
Kartika Dyah Palupi ◽  
Ahmad Fathoni ◽  
Andria Agusta
Keyword(s):  
Antioxidant Activity ◽  
Antibacterial Activity ◽  
Plant Species ◽  
Antioxidant Activities ◽  
Antioxidant Properties ◽  
Total Phenolic ◽  
Antioxidant Agents ◽  
Ethanolic Extracts ◽  
Potential Sources ◽  
Weak Antibacterial Activity

The discovery of new antibiotics to overcome the growing resistance problem as well as the discovery of new natural, safe antioxidants to combat oxidative stress are still urgently needed. Medicinal plants are known to produce potential therapeutic substances which are more biologically selective than synthetic compounds. Therefore, we explored the bioactivities of 35 ethanolic extracts from 24 underexplored plant species collected in Halmahera, to find potential sources for antibacterial and antioxidant agents.  Dried plant parts were extracted using ethanol 96%. Thin layer chromatography-direct-bioautography (TLC-DB) and minimum inhibitory concentration (MIC) determination were used to evaluate the antibacterial effect. Antioxidant activity was determined against DPPH using TLC-DB and microdilution assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu’s method. The ethanolic extracts exhibited moderate to weak antibacterial activity against Escherichia coli and Staphylococcus aureus. However, the leaf extract of Elaeocarpus dolichostylus, Elaeocarpus multiflorus, and Psychotria celebica as well as the stem bark extract of Elaeocarpus dolichostylus, Cinnamomum sintoc, and Garcinia latissima displayed very strong antioxidant activities against DPPH with AAI values between 4.60 to 13.42. A strong correlation between TPC and antioxidant activity with r = 0.8712 was observed. Despite the moderate to weak antibacterial activity, eight underexplored plant species exhibit strong antioxidant activities. A high correlation between TPC and antioxidant activity indicating a prominent role of phenolic compounds in the plants’ antioxidant properties. These findings indicate that collected plants from Halmahera are potential to be studied and developed further as the potential sources for novel antioxidants.

scholarly journals Synthesis, Characterization and Antibacterial Activity of Schiff Bases and their Metal Complexes Derived from 4-Acyl-1-phenyl-3-methyl-2-pyrazolin-5-ones and 2-Amino-4(4'-methylphenyl)-thiazole

2010 ◽  
Vol 7 (4) ◽  
pp. 1396-1406 ◽  
Author(s):  
A. S. Thakar ◽  
K. K. Singh ◽  
K. T. Joshi ◽  
A. M. Pancholi ◽  
K. S. Pandya
Keyword(s):  
Antibacterial Activity ◽  
Schiff Bases ◽  
Elemental Analysis ◽  
Mass Spectra ◽  
Nmr Spectra ◽  
Electrical Conductance ◽  
H Nmr ◽  
Infrared Spectral ◽  
Ft Ir ◽  
C Nmr

4-Acyl-1-phenyl-3-methyl-2-pyrazolin-5-ones condensed with 2-amino-4(4'-methylphenyl)-thiazole to form Schiff base. These Schiff bases from complexes of type ML22H2O (M=Mn, Fe, Co, Ni and Cu). Elemental analysis, magnetic susceptibility, electrical conductance, electronic and Infrared spectral data suggested octahedral structure for the complexes. All the compounds were tested for their antibacterial activity. The result indicates that the growth of the tested organism was inhibited by most of the compounds. These Schiff bases are characterized by elemental analysis, mass spectra,1H-NMR spectra,13C NMR spectra and FT IR spectra.

scholarly journals Synthesis, Antibacterial and Antioxidant Evaluation of Novel 1-(5,7-Dichloro-1,3-benzoxazol-2-yl)-1H-pyrazolo[3,4-b]quinoline Derivatives

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
N. D. Jayanna ◽  
H. M. Vagdevi ◽  
J. C. Dharshan ◽  
T. R. Prashith Kekuda
Keyword(s):  
Antibacterial Activity ◽  
Antioxidant Activities ◽  
Biological Activities ◽  
Spectral Studies ◽  
Quinoline Derivatives ◽  
Mass Spectral ◽  
H Nmr ◽  
Antioxidant Evaluation ◽  
Target Molecules ◽  
C Nmr

Some novel 1-(5,7-dichloro-1,3-benzoxazol-2-yl)-1H-pyrazolo[3,4-b]quinoline derivatives8(a–f) were synthesized by reacting 5,7-dichloro-2-hydrazino-1,3-benzoxazole4and substituted-2-chloro-3-quinoline carbaldehydes usingp-toluenesulfonic acid (PTSA) as a catalyst for the cyclisation. The target molecules have been characterized by IR,1H NMR,13C NMR, and mass spectral studies. The synthesized compounds were screened for biological activities, and some of the compounds have exhibited encouraging antibacterial and antioxidant activities. The compounds8aand8eshowed potent antibacterial activity, whereas the compounds8eand8fact as antioxidants.

Large-scale High-throughput Screening Revealed 5'-(carbonylamino)-2,3'- bithiophene-4'-carboxylate as Novel Template for Antibacterial Agents

2020 ◽  
Vol 17 (5) ◽  
pp. 716-724
Author(s):  
Yan A. Ivanenkov ◽  
Renat S. Yamidanov ◽  
Ilya A. Osterman ◽  
Petr V. Sergiev ◽  
Vladimir A. Aladinskiy ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
High Throughput ◽  
High Throughput Screening ◽  
Large Scale ◽  
Antibacterial Agents ◽  
Sos Response ◽  
Luciferase Assay ◽  
Translational Machinery ◽  
E Coli ◽  
New Class

Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique. Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay. Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment. Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign.

Green Synthesis, Characterization, DPPH and Ferrous Ion-chelating (FIC) Activity of Tetrakis-Schiff’s Bases of Terephthalaldehyde

2019 ◽  
Vol 16 (3) ◽  
pp. 249-255
Author(s):  
Momin Khan ◽  
Umar Ali ◽  
Anis Ur Rahman ◽  
Muhammad Ibrahim ◽  
Abdul Hameed ◽  
...  
Keyword(s):  
Antioxidant Activities ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Aromatic Aldehydes ◽  
Ferrous Ion ◽  
Future Research ◽  
Scavenging Activity ◽  
Schiff’S Bases ◽  
Schiff's Bases ◽  
Antioxidant Agents

Background: The role of small molecules as antioxidants to prevent the oxidation of other molecules and inhibit them from radical formation is the area of much interest to cure disease especially cancer. Moreover, the antioxidants play important role as stabilizers to prevent oxidation of fuels and lubricants. </P><P> Methods: In the present study, fifteen tetrakis-Schiff’s bases derivatives (1-15) were synthesized and screened for their antioxidant activities. Compounds 1-15 were synthesized by continuous stirring of reaction mixture of 1,4-bis (hydrazonomethyl)benzene (1 mmol) with various substituted aromatic aldehydes (2 mmol) in distilled water using acetic acid as catalyst at room temperature for 2-10 min. </P><P> Results: Our present study showed that all compounds are better ferrous ion-chelating agents except compound 1,4-bis((E)-((E)-(3,4-dimethoxybenzylidene)hydrazono)methyl)benzene (6) (IC50 = 329.26 &#177; 4.75 &#181;M) which has slightly low activity than the standard EDTA (IC50 = 318.40 &#177; 5.53 μM). In addition, DPPH radical scavenging activity of eleven compounds showed higher activity than the standard. However, remaining four compounds showed comparable radical scavenging activity to the standard DPPH (IC50 = 257.77 &#177; 4.60 &#181;M). </P><P> Conclusion: The series of fifteen Schiff’s bases (1-15) were synthesized and evaluated as antioxidants. From both assays, it has been demonstrated that most of the tetrakis-Schiff’s bases have potential to serve as leads for the development of antioxidant agents for future research.

Recent Advances in 1,3,5-Triazine Derivatives as Antibacterial Agents

2020 ◽  
Vol 17 (8) ◽  
pp. 991-1041
Author(s):  
Divya Utreja ◽  
Jagdish Kaur ◽  
Komalpreet Kaur ◽  
Palak Jain
Keyword(s):  
Antibacterial Activity ◽  
Heterocyclic Compounds ◽  
Antibacterial Agents ◽  
Rapid Development ◽  
Pharmacological Action ◽  
Biological Properties ◽  
Vast Array ◽  
Bacterial Diseases ◽  
New Class ◽  
Triazine Derivatives

Triazine, one of the nitrogen containing heterocyclic compounds has attracted the considerable interest of researchers due to the vast array of biological properties such as anti-viral, antitumor, anti-convulsant, analgesic, antioxidant, anti-depressant, herbicidal, insecticidal, fungicidal, antibacterial and anti-inflammatory activities offered by it. Various antibacterial agents have been synthesized by researchers to curb bacterial diseases but due to rapid development in drug resistance, tolerance and side effects, there had always been a need for the synthesis of a new class of antibacterial agents that would exhibit improved pharmacological action. Therefore, this review mainly focuses on the various methods for the synthesis of triazine derivatives and their antibacterial activity.

Investigation of Compounds and Biological Activity of Selected Indonesian Marine Sponges

2020 ◽  
Vol 10 (3) ◽  
pp. 312-321
Author(s):  
Idin Sahidin ◽  
Carla W. Sabandar ◽  
Wahyuni ◽  
Rini Hamsidi ◽  
Sandra Aulia Mardikasari ◽  
...  
Keyword(s):  
Biological Activity ◽  
Antioxidant Activities ◽  
Chemical Constituents ◽  
Radical Scavenging Activity ◽  
Radical Scavenging ◽  
Marine Sponges ◽  
Chemical Screening ◽  
Methanol Extracts ◽  
Ms Analysis ◽  
Antioxidant Agents

Background: Marine sponges provided a great source of natural products with promising biological activity. This study was aimed to investigate the chemical constituents of methanol extracts of selected Indonesian marine sponges (Callyspongia sp., Clathria sp., Melophlus sarasinorum, and Xestospongia sp.), collected from the Saponda Islands, Southeast Sulawesi, Indonesia as well as to evaluate their antimicrobial and antioxidant activities. Methods: LCMS/MS analysis used to identify the compounds. Agar well diffusion and DPPH assays were used to evaluate the antimicrobial and antioxidant activities. Results: Chemical screening reported alkaloids, terpenoids, steroids, and saponins from all investigated sponges. The LC-MS/MS analysis identified various compounds which mainly contained steroids. Antimicrobial activity (against Bacillus subtilis, Escherichia coli, Salmonella enterica, and Candida albicans) was only shown by the Xestospongia sp. extract. Meanwhile, extracts of M. sarasinorum, Xestospongia sp., and Callyspongia sp. exhibited potent radical scavenging activity. Conclusion: The study concluded that the selected sponges could provide various groups of compounds. Methanol extracts of these sponges could be used as sources of antimicrobial and antioxidant agents.

Conformational structure of ethylene glycol dibenzoate. Vibrational and NMR spectra

1981 ◽  
Vol 46 (8) ◽  
pp. 1913-1929 ◽  
Author(s):  
Bohdan Schneider ◽  
Pavel Sedláček ◽  
Jan Štokr ◽  
Danica Doskočilová ◽  
Jan Lövy
Keyword(s):  
Ethylene Glycol ◽  
Vibrational Spectra ◽  
Nmr Spectra ◽  
Coupling Constants ◽  
Conformational Structure ◽  
Infrared And Raman Spectra ◽  
H Nmr ◽  
Liquid States ◽  
Crystalline Forms ◽  
C Nmr

It was found that three crystalline forms of ethylene glycol dibenzoate can be prepared. Infrared and Raman spectra of these three forms, as well as of the glassy and liquid states, were measured. From 3JHH coupling constants obtained by analysis of the 13C satellite band of the -CH2- group in 1H NMR spectra, and from the 3JCH coupling constants of the -CO.O.CH2- fragment obtained by analysis of the carbonyl band in 13C NMR spectra it was found that in the liquid state the -CH2-CH2- group exists predominantly in the gauche conformational structure, and the bonds C-O-C-C assume predominantly a trans orientation. The results of the analysis of NMR and vibrational spectra were used for the structural interpretation of conformationally sensitive bands in vibrational spectra of ethylene glycol dibenzoate.

13C NMR spectra of 1-aryl-ferrocenylethylenes

1986 ◽  
Vol 51 (3) ◽  
pp. 670-676 ◽  
Author(s):  
Eva Solčániová ◽  
Štefan Toma ◽  
Tibor Liptaj
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Substituent Effects ◽  
13C Nmr Spectra ◽  
Bridge Group ◽  
C Nmr ◽  
Electron Effects

13C NMR spectra of 18 ferrocene analogues of trans stilbenes (1-aryl-2-ferrocenylethylenes) were measured. It was found that bridge group weakens the transfer of the substituent electron effects into ferrocene nucleus, especially distinctly into 3',4'positions of cyclopentadienyl ring. The transfer of substituent effects into β-position of the bridge -CH=CH- is greater in derivatives studied by us than in stilbenes. Synthesis of 1-(4-dimethylaminophenyl)-2-ferrocenylethylene is described.

The synthesis and stereochemistry of the ternary cobalt(III) complex with a stereospecific ligand derived from (S)-leucine

1986 ◽  
Vol 51 (2) ◽  
pp. 318-326 ◽  
Author(s):  
Milan Strašák ◽  
Pavol Novomeský
Keyword(s):  
Ir Spectroscopy ◽  
Aqueous Medium ◽  
Absorption Spectroscopy ◽  
Absolute Configuration ◽  
Nmr Spectra ◽  
Methyl Groups ◽  
Electron Absorption Spectroscopy ◽  
Electron Absorption ◽  
C Nmr

A new stereospecific ligand, ethylenediamine-N,N'-di(S)-α-isocapronic acid, was synthesized by condensation of (S)-leucine with 1,2-dibromoethane in alkaline aqueous medium. It follows from the 1H and 13C NMR spectra that the terminal methyl groups are chemically and magnetically nonequivalent. Of the four theoretically possible isomers of the ternary cobalt (III) complex with ethylenediamine, separation on catex yielded only one, whose absolute configuration was determined by a combination of 1H and 13C NMR, electron absorption spectroscopy and CD and IR spectroscopy.

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