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1.
Int J Mol Sci ; 24(1)2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36614204

RESUMO

The three Schiff base ligands, derivatives of hesperetin, HHSB (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]isonicotinohydrazide), HIN (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]benzhydrazide) and HTSC (N-[2,3-dihydro-5,7-dihydroxy-2-(3-hydroxy-4-methoxyphenyl)chromen-4-ylidene]thiosemicarbazide) and their copper complexes, CuHHSB, CuHIN, and CuHTSC were designed, synthesized and analyzed in terms of their spectral characterization and the genotoxic activity. Their structures were established using several methods: elemental analysis, FT-IR, UV-Vis, EPR, and ESI-MS. Spectral data showed that in the acetate complexes the tested Schiff bases act as neutral tridentate ligand coordinating to the copper ion through two oxygen (or oxygen and sulphur) donor atoms and a nitrogen donor atom. EPR measurements indicate that in solution the complexes keep their structures with the ligands remaining bound to copper(II) in a tridentate fashion with (O-, N, Oket) or (O-, N, S) donor set. The genotoxic activity of the compounds was tested against model tumour (HeLa and Caco-2) and normal (LLC-PK1) cell lines. In HeLa cells the genotoxicity for all tested compounds was noticed, for HHSB and CuHHSB was the highest, for HTSC and CuHTSC-the lowest. Generally, Cu complexes displayed lower genotoxicity to HeLa cells than ligands. In the case of Caco-2 cell line HHSB and HTSC induced the strongest breaks to DNA. On the other side, CuHHSB and CuHTSC induced the highest DNA damage against LLC-PK1.


Assuntos
Complexos de Coordenação , Cobre , Humanos , Cobre/farmacologia , Cobre/química , Bases de Schiff/farmacologia , Bases de Schiff/química , Espectroscopia de Infravermelho com Transformada de Fourier , Células HeLa , Células CACO-2 , Oxigênio , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Ligantes
2.
Molecules ; 28(1)2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36615615

RESUMO

The present work reports the synthesis of new N4-donor compounds carrying p-xylyl spacers in their structure. Different Schiff base aliphatic N-donors were obtained synthetically and subsequently evaluated for their ability to interact with two models of nucleic acids: calf-thymus DNA (CT-DNA) and the RNA from yeast Saccharomyces cerevisiae (herein simply indicated as RNA). In more detail, by condensing p-xylylenediamine and a series of aldehydes, we obtained the following Schiff base ligands: 2-thiazolecarboxaldehyde (L1), pyridine-2-carboxaldehyde (L2), 5-methylisoxazole-3-carboxaldehyde (L3), 1-methyl-2-imidazolecarboxaldehyde (L4), and quinoline-2-carboxaldehyde (L5). The structural characterisation of the ligands L1-L5 (X-ray, 1H NMR, 13C NMR, elemental analysis) and of the coordination polymers {[CuL1]PF6}n (herein referred to as Polymer1) and {[AgL1]BF4}n, (herein referred to as Polymer2, X-ray, 1H NMR, ESI-MS) is herein described in detail. The single crystal X-ray structures of complexes Polymer1 and Polymer2 were also investigated, leading to the description of one-dimensional coordination polymers. The spectroscopic and in silico evaluation of the most promising compounds as DNA and RNA binders, as well as the study of the influence of the 1D supramolecular polymers Polymer1 and Polymer2 on the proliferation of Escherichia coli bacteria, were performed in view of their nucleic acid-modulating and antimicrobial applications. Spectroscopic measurements (UV-Vis) combined with molecular docking calculations suggest that the thiazolecarboxaldehyde derivative L1 is able to bind CT-DNA with a mechanism different from intercalation involving the thiazole ring in the molecular recognition and shows a binding affinity with DNA higher than RNA. Finally, Polymer2 was shown to slow down the proliferation of bacteria much more effectively than the free Ag(I) salt.


Assuntos
Anti-Infecciosos , Complexos de Coordenação , Simulação de Acoplamento Molecular , RNA , Bases de Schiff/química , DNA/química , Polímeros , Ligantes , Complexos de Coordenação/química
3.
Food Res Int ; 163: 112187, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36596128

RESUMO

Quinones are electrophilic compounds that can undergo Michael addition or Schiff base reaction with nucleophilic amines, but the effect of temperature has not been systematically studied. The aim of this study was to characterize how temperature affects the reaction mechanism and kinetics of 4-methylbenzoquinone (4MBQ) with lysine (Lys), Nα-acetyl Lys or Nε-acetyl Lys. The products were identified and characterized by LC-MS/MS, which revealed formation of Michael addition products, Schiff base, and a di-adduct in Lys and Nα-acetyl Lys-containing reaction mixtures. The product profiles were not affected by temperature in the range of 15-100 °C. NMR analysis proved that Michael addition of Nα-acetyl Lys occurred on the C5 position of 4MBQ. Rate constants for the reactions studied by stopped-flow UV-vis spectrophotometry under pseudo-first-order conditions where the amines were present in excess in the range 15 °C to 45 °C showed the α-amino groups of Lys are more reactive than the ε-groups. The kinetics results revealed that the temperature dependence of reaction rates followed the Arrhenius law, with activation energies in the order: Lys < Nε-acetyl Lys < Nα-acetyl Lys. Our results provide detailed knowledge about the temperature dependence of the reaction between Lys residues and quinones under conditions relevant for storage of foods.


Assuntos
Lisina , Bases de Schiff , Lisina/química , Cromatografia Líquida , Temperatura , Espectrometria de Massas em Tandem , Aminas , Quinonas
4.
J Chromatogr A ; 1689: 463759, 2023 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-36599193

RESUMO

Schiff base networks (SNWs) were introduced as a new stir bar coating, and a method of SNWs- coated stir bar sorptive extraction (SBSE) coupled to high performance liquid chromatography-ultraviolet detector (HPLC-UV) was developed for determination of pyrethroid pesticide residues in tobacco. The prepared amorphous SNWs polymer from melamine and 3,5-dihydroxybenzaldehyde riches in triazine rings, hydroxyl groups and amino groups, and the SNWs/polydimethylsiloxane (PDMS) stir bar prepared by sol-gel method can extract weakly polar pyrethroid pesticides through hydrophobic, π-π and hydrogen bonding. The SNWs/PDMS stir bar exhibited high extraction efficiency toward pyrethroid pesticides (70-76%) and good mechanical stability with reused time more than 50 times. Under the optimal experimental conditions, the limits of detection were 0.20 - 0.66 µg/L with relative standard deviation varying in the range of 2.3-8.2%, which meets the requirements of trace analysis of pesticide residues in the tobacco industry. The method was applied to the determination of six pyrethroid pesticides in cigarette samples, and the recovery for the spiked samples ranged from 82 to 117%, showing a great applicability for the analysis of pesticide residues in real samples with a complex sample matrix.


Assuntos
Resíduos de Praguicidas , Praguicidas , Piretrinas , Tabaco , Limite de Detecção , Bases de Schiff , Cromatografia Líquida de Alta Pressão/métodos , Reprodutibilidade dos Testes
5.
Molecules ; 28(2)2023 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-36677536

RESUMO

A new series of Schiff-benzimidazole hybrids 3a-o has been designed and synthesized. The structure of the target compounds was proved by different spectroscopic and elemental analysis tools. The target compounds were evaluated for their in vitro cytotoxic activity against 60 cancer cell lines according to NCI single- and five-dose protocols. Consequently, four compounds were further examined against the most sensitive lung cancer A549 and NCI-H460 cell lines. Compounds 3e and 3g were the most active, achieving 3.58 ± 0.53, 1.71 ± 0.17 and 1.88 ± 0.35, 0.85 ± 0.24 against A549 and NCI-H460 cell lines, respectively. Moreover, they showed remarkable inhibitory activity on the VEGFR-2 TK with 86.23 and 89.89%, respectively, as compared with Sorafenib (88.17%). Moreover, cell cycle analysis of NCI-H460 cells treated with 3e and 3g showed cellular cycle arrest at both G1 and S phases (supported by caspases-9 study) with significant pro-apoptotic activity, as indicated by annexin V-FITC staining. The binding interactions of these compounds were confirmed through molecular docking studies; the most active compounds displayed complete overlay with, and a similar binding mode and pose to, Sorafenib, a reference VEGFR-2 inhibitor.


Assuntos
Antineoplásicos , Receptor 2 de Fatores de Crescimento do Endotélio Vascular , Estrutura Molecular , Relação Estrutura-Atividade , Sorafenibe/farmacologia , Simulação de Acoplamento Molecular , Bases de Schiff/farmacologia , Proliferação de Células , Antineoplásicos/química , Benzimidazóis/química , Ensaios de Seleção de Medicamentos Antitumorais , Desenho de Fármacos , Apoptose
6.
Arch Biochem Biophys ; 733: 109471, 2023 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-36522814

RESUMO

NahE is a hydratase-aldolase that converts o-substituted trans-benzylidenepyruvates (H, OH, or CO2-) to benzaldehyde, salicylaldehyde, or 2-carboxybenzaldehyde, respectively, and pyruvate. The enzyme is in a bacterial degradative pathway for naphthalene, which is a toxic and persistent environmental contaminant. Sequence, crystallographic, and mutagenic analysis identified the enzyme as a member of the N-acetylneuraminate lyase (NAL) subgroup in the aldolase superfamily. As such, it has a conserved lysine (Lys183) and tyrosine (Tyr155), for Schiff base formation, as well as a GXXGE motif for binding of the pyruvoyl carboxylate group. A crystal structure of the selenomethionine derivative of NahE shows these active site elements along with nearby residues that might be involved in the mechanism and/or specificity. Mutations of five active site amino acids (Thr65, Trp128, Tyr155, Asn157, and Asn281) were constructed and kinetic parameters measured in order to assess the effect(s) on catalysis. The results show that the two Trp128 mutants (Phe and Tyr) have the least effect on catalysis, whereas amino acids with bulky side chains at Thr65 (Val) and Asn281 (Leu) have the greatest effect. Changing Tyr155 to Phe and Asn157 to Ala also hinders catalysis, and the effects fall in between these extremes. These observations are put into a structural context using a crystal structure of the Schiff base of the reaction intermediate. Trapping experiments with substrate, Na(CN)BH3, and wild type enzyme and selected mutants mostly paralleled the kinetic analysis, and identified two salicylaldehyde-modified lysines: the active site lysine (Lys183) and one outside the active site (Lys279). The latter could be responsible for the observed inhibition of NahE by salicylaldehyde. Together, the results provide new insights into the NahE-catalyzed reaction.


Assuntos
Frutose-Bifosfato Aldolase , Bases de Schiff , Frutose-Bifosfato Aldolase/genética , Cinética , Bases de Schiff/química , Bases de Schiff/metabolismo , Lisina , Mutagênicos , Sítios de Ligação , Aldeído Liases/química , Catálise , Hidrolases/metabolismo , Naftalenos , Especificidade por Substrato
7.
Int J Biol Macromol ; 226: 336-344, 2023 Jan 31.
Artigo em Inglês | MEDLINE | ID: mdl-36502945

RESUMO

A new chitosan 2,4-dihydroxyacetophenone Schiff base @SrFe12O19 (Cs-SB@SrFe12O19) nanocomposite was successfully prepared by one-pot reaction and fully characterized for its functional groups, morphology, elemental analysis and thermal behavior by FT-IR, XRD, VSM, DSC, TGA, zeta potential, FE-SEM and EDS techniques. The VSM result showed that Cs-SB@SrFe12O19 has Ms of 11.81 emu/g and Hc of 5488 Oe, known as hard magnetic material. Finally, the as-prepared sample utilized as a new sorbent for the removal of Pb(II) ions from aqueous solution by using batch adsorption experiments. The adsorption of Pb(II) was carried out at different pH, contact time and initial dose of Cs-SB@SrFe12O19. The maximum adsorption capacity was found to be 132 mg/g (99 %) at pH 5 and the contact time of 120 min. Finally, the kinetic studies reveals that the adsorption process of Cs-SB@SrFe12O19 followed by the pseudo second order kinetics model. Also, the sample showed excellent recyclable efficiency up to 5 cycles.


Assuntos
Quitosana , Nanocompostos , Poluentes Químicos da Água , Quitosana/química , Chumbo , Espectroscopia de Infravermelho com Transformada de Fourier , Bases de Schiff/química , Cinética , Água/química , Adsorção , Nanocompostos/química , Poluentes Químicos da Água/química , Concentração de Íons de Hidrogênio
8.
Dalton Trans ; 52(2): 434-443, 2023 Jan 03.
Artigo em Inglês | MEDLINE | ID: mdl-36524392

RESUMO

In this article, a novel triphenylamine-modified salicylaldehyde Schiff base 2-(((4-(diphenylamino)phenyl)imino)methyl)-4-(pyridine-4-yl)phenol (HL) was synthesized and structurally characterized. HL possessed D-π-A structure and exhibited typical AIE property in THF/H2O. It was applied to selectively recognize Cu2+ through an on-off mode in THF/H2O (1/9, v/v), and the fluorescence attenuation was attributed to a paramagnetic quenching effect of Cu2+ together with the abatement of HL aggregates. Hence, the detection limit achieved was as low as 1.32 × 10-7 M. The spectroscopic and ESI-HRMS results revealed a 1 : 2 complexation ratio of Cu2+ with HL. The mechanism for sensing Cu2+ was further confirmed by performing DFT calculations. Owing to the large affinity between Cu2+ and His, the resultant CuL2 system was further used to detect His via the off-on method based on the displacement of ligands. The detection limit for His reached 5.14 × 10-8 M. Furthermore, HL was available to prepare handy indicator papers for the on-site recognition of Cu2+ and His. Confocal fluorescent imaging demonstrated that HL could sequentially respond to intracellular Cu2+ and His.


Assuntos
Cobre , Bases de Schiff , Bases de Schiff/química , Espectrometria de Fluorescência , Cobre/química
9.
Bioorg Chem ; 131: 106309, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36502567

RESUMO

A novel set of quinoline tailored with the sulfonamide as zinc-binding group (ZBG) has been rationalized and synthesized as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors. Such hybrids were decorated by a novel elongated imine linker with/without ethylene spacer with variable hydrophobic and lipophilic pockets. Therefore, a regioisomeric tactic has been established, most of which act as efficient inhibitors of the tumor-associated CA isoforms IX and XII. Interestingly, one hybrid 10b displayed an appreciable activity in MCF-7 cell line under normoxic condition (IC50 of 8.42 µM) in comparison to the standard staurosporine (IC50 = 5.34 µM) and excellent activity under hypoxic conditions (IC50 = 1.56 µM) in comparison to staurosporine (IC50 = 4.45 µM). Furthermore, hybrids 8a and 10b encouraged MCF-7 and MDA-MB-231 cell apoptosis alongside promising Bax/Bcl expression ratio change. Docking studies were also, performed and agreed with the biological results. Our SAR study suggested that our regiosiomerization tactic for the quinoline based-sulfonamide molecules led to effective inhibition of tumuor-relevant hCAs IX/XII.


Assuntos
Anidrases Carbônicas , Neoplasias , Quinolinas , Humanos , Bases de Schiff/química , Estrutura Molecular , Relação Estrutura-Atividade , Estaurosporina , Inibidores da Anidrase Carbônica/química , Anidrases Carbônicas/metabolismo , Neoplasias/tratamento farmacológico , Antígenos de Neoplasias/metabolismo , Isoformas de Proteínas/metabolismo , Sulfonamidas/farmacologia , Sulfonamidas/química , Quinolinas/farmacologia
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 289: 122242, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36542920

RESUMO

Naphthol hydrazone derivatives are recognized as efficient chelating agents for both qualitative and quantitative detection of metal ions. Here we design a naphthol hydrazine-based chemosensor with covalently linking a strong electron-withdrawing benzothiadiazole group to modulate the molecular electronic structure, nominated as NtHzBtd. The fluorescent probe performs excellent selectivity and sensitivity towards Fe3+ with 1:1 binding stoichiometry, while exhibiting a quick response at 55 s with a relatively low limit of detection of 0.036 µM. A series of spectroscopic measurements in tandem with theoretical calculations suggest that the probe undergoes both intramolecular charge transfer (ICT) and chelation enhanced quenching (CHEQ) processes. Successful color rendering of paper strips and bioimaging in PC3 cells demonstrate the promising applicability of NtHzBtd for portable Fe3+ detection in real samples and biosystems.


Assuntos
Naftóis , Bases de Schiff , Humanos , Naftóis/química , Células PC-3 , Bases de Schiff/química , Hidrazonas , Corantes Fluorescentes/química
11.
Molecules ; 27(23)2022 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-36500611

RESUMO

Four new heterometallic complexes combining [MII(H2dapsc)]2+ cations with the chelating H2dapsc {2,6-diacetylpyridine-bis(semicarbazone)} Schiff base ligand and [Cr(CN)6]3- anion were synthesized: {[MII(H2dapsc)]CrIII(CN)6K(H2O)2.5(EtOH)0.5}n·1.2n(H2O), M = Mn (1) and Co (2), {[Mn(H2dapsc)]2Cr(CN)6(H2O)2}Cl·H2O (3) and {[Co(H2dapsc)]2Cr(CN)6(H2O)2}Cl·2EtOH·3H2O (4). In all the compounds, M(II) centers are seven-coordinated by N3O2 atoms of H2dapsc in the equatorial plane and N or O atoms of two apical -CN/water ligands. Crystals 1 and 2 are isostructural and contain infinite negatively charged chains of alternating [MII(H2dapsc)]2+ and [CrIII(CN)6]3- units linked by CN-bridges. Compounds 3 and 4 consist of centrosymmetric positively charged trimers in which two [MII(H2dapsc)]2+ cations are bound through one [CrIII(CN)6]3- anion. All structures are regulated by π-stacking of coplanar H2dapsc moieties as well as by an extensive net of hydrogen bonding. Adjacent chains in 1 and 2 interact also by coordination bonds via a pair of K+ ions. The compounds containing MnII (1, 3) and CoII (2, 4) show a significant difference in magnetic properties. The ac magnetic measurements revealed that complexes 1 and 3 behave as a spin glass and a field-induced single-molecule magnet, respectively, while 2 and 4 do not exhibit slow magnetic relaxation in zero and non-zero dc fields. The relationship between magnetic properties and non-covalent interactions in the structures 1-4 was traced.


Assuntos
Magnetismo , Bases de Schiff , Cristalografia por Raios X , Ligantes , Bases de Schiff/química , Fenômenos Magnéticos
12.
Acta Chim Slov ; 69(4): 913-919, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36562166

RESUMO

A bis-Schiff base N,N'-ethylene-bis(3-bromosalicylaldimine) (H2L) was prepared from 3-bromosalicylaldehyde and ethane-1,2-diamine. With H2L as ligand, a new copper(II) complex [CuL] (1) and a new cobalt(III) complex [CoL(NCS)(DMF)] (2) were prepared and characterized by physico-chemical methods and single crystal X-ray analysis. X-ray analysis indicates that the Cu atom in complex 1 is in square planar coordination, and the Co atom in complex 2 is in octahedral coordination. The compounds were tested in vitro for their antibacterial activities on Bacillus subtilis, Staphylococcus aureus, Escherichia coli and Pseudomonas fluorescens. Both complexes have effective activities on the bacteria.


Assuntos
Complexos de Coordenação , Cobre , Cobre/química , Cobalto/química , Bactérias , Antibacterianos/farmacologia , Antibacterianos/química , Etilenos , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química , Bases de Schiff/química , Cristalografia por Raios X
13.
Inorg Chem ; 61(51): 20757-20773, 2022 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-36519680

RESUMO

A hydrophobic Schiff base catecholate vanadium complex was recently discovered to have anticancer properties superior to cisplatin and suited for intratumoral administration. This [VO(HSHED)(DTB)] complex, where HSHED is N-(salicylideneaminato)-N'-(2-hydroxyethyl)-1,2-ethanediamine and the non-innocent catecholato ligand is di-t-butylcatecholato (DTB), has higher stability compared to simpler catecholato complexes. Three new chloro-substituted Schiff base complexes of vanadium(V) with substituted catecholates as co-ligands were synthesized for comparison with their non-chlorinated Schiff base vanadium complexes, and their properties were characterized. Up to four geometric isomers for each complex were identified in organic solvents using 51V and 1H NMR spectroscopies. Spectroscopy was used to characterize the structure of the major isomer in solution and to demonstrate that the observed isomers are exchanged in solution. All three chloro-substituted Schiff base vanadium(V) complexes with substituted catecholates were also characterized by UV-vis spectroscopy, mass spectrometry, and electrochemistry. Upon testing in human glioblastoma multiforme (T98g) cells as an in vitro model of brain gliomas, the most sterically hindered, hydrophobic, and stable compound [t1/2 (298 K) = 15 min in cell medium] was better than the two other complexes (IC50 = 4.1 ± 0.5 µM DTB, 34 ± 7 µM 3-MeCat, and 19 ± 2 µM Cat). Furthermore, upon aging, the complexes formed less toxic decomposition products (IC50 = 9 ± 1 µM DTB, 18 ± 3 µM 3-MeCat, and 8.1 ± 0.6 µM Cat). The vanadium complexes with the chloro-substituted Schiff base were more hydrophobic, more hydrolytically stable, more easily reduced compared to their corresponding parent counterparts, and the most sterically hindered complex of this series is only the second non-innocent vanadium Schiff base complex with a potent in vitro anticancer activity that is an order of magnitude more potent than cisplatin under the same conditions.


Assuntos
Complexos de Coordenação , Vanádio , Humanos , Vanádio/farmacologia , Vanádio/química , Cisplatino , Bases de Schiff/farmacologia , Bases de Schiff/química , Água , Espectroscopia de Ressonância Magnética , Complexos de Coordenação/farmacologia , Ligantes
14.
Acta Chim Slov ; 69(4): 772-778, 2022 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-36562158

RESUMO

The current study reports synthesis, structure establishment, anti-glycation, and anti-oxidant activities of ligand 4-[(2-hydroxynaphthalene-1-ylmethylene)-amino]-benzenesulfonamide (L) and its coordination compounds with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) metal ions. The analytical techniques used (UV-Vis, FT-IR, CHN/S) confirmed the bidentate nature of the ligand, coordinating via O and N atoms in 2:1 ligand-to-metal ratio. The TG/DTA anylsis displayed that these compounds are thermally stable. Furthermore, the synthesized compounds were evaluated for their anti-glycation and antioxidant potential and showed significant activities with IC50 values range 184.11-386.34 µM and 37.05-126.27 µM, respectively. The Mn (IC50 = 184.11 ± 2.11 µM), Ni (IC50 = 211.26 ± 1.46 µM), Cu (IC50 = 254.56 ± 1.16 µM), and Zn (IC50 = 276.43 ± 2.14 µM) metal complexes exhibited substantial anti-glycation activity and comparatively better activity than the standard rutin (IC50 = 294.4 ± 1.50 µM), whereas Zn complex (IC50 = 37.05 ± 1.53 µM) also showed better DPPH radical scavenging activity than the standard tert-butyl-4-hydroxyanisole (IC50 = 44.7 ± 1.21 µM).


Assuntos
Antioxidantes , Complexos de Coordenação , Bases de Schiff , Sulfanilamida , Ligantes , Espectroscopia de Ressonância Magnética , Metais , Testes de Sensibilidade Microbiana , Bases de Schiff/síntese química , Bases de Schiff/química , Espectroscopia de Infravermelho com Transformada de Fourier , Sulfanilamida/análogos & derivados , Sulfanilamida/síntese química , Sulfanilamida/química
15.
Molecules ; 27(24)2022 Dec 14.
Artigo em Inglês | MEDLINE | ID: mdl-36558007

RESUMO

Quercetin is one of the most powerful bioactive dietary flavonoids. The in vivo biological study of quercetin is extremely difficult due to its very low solubility. However, diorganotin complexes of quercetin are more useful when contrasted with quercetin due to increased solubility. In the present study, quercetin, substituted biguanide synthesized in the form of Schiff base and its di-alkyl/aryl tin (IV) complexes were obtained by condensing Schiff base with respective di-alkyl/aryl tin (IV) dichloride. Advanced analytical techniques were used for structural elucidation. The results of biological screening against Gram-positive/Gram-negative bacteria and fungi showed that these diorganotin (IV) derivatives act as potent antimicrobial agents. The in silico investigation with dihydropteroate (DHPS) disclosed a large ligand-receptor interaction and revealed a strong relationship between the natural exercises and computational molecular docking results.


Assuntos
Complexos de Coordenação , Estanho , Simulação de Acoplamento Molecular , Flavonoides/farmacologia , Quercetina/farmacologia , Bases de Schiff/farmacologia , Bases de Schiff/química , Bactérias Gram-Negativas , Bactérias Gram-Positivas
16.
Int J Mol Sci ; 23(23)2022 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-36499170

RESUMO

Metal complexes play a crucial role in pharmaceutical sciences owing to their wide and significant activities. Schiff bases (SBs) are multifaceted pharmacophores capable of forming chelating complexes with various metals in different oxidation states. Complexes with SBs are extensively studied for their numerous advantages, including low cost and simple synthetic strategies. They have been reported to possess a variety of biological activities, including antimicrobial, anticancer, antioxidant, antimalarial, analgesic, antiviral, antipyretic, and antidiabetic ones. This review summarizes the most recent studies on the antimicrobial and antiproliferative activities of SBs-metal complexes. Moreover, recent studies regarding mononuclear and binuclear complexes with SBs are described, including antioxidant, antidiabetic, antimalarial, antileishmanial, anti-Alzheimer, and catecholase activities.


Assuntos
Anti-Infecciosos , Complexos de Coordenação , Complexos de Coordenação/farmacologia , Bases de Schiff , Metais , Antioxidantes/farmacologia , Coleta de Dados
17.
Int J Mol Sci ; 23(23)2022 Nov 29.
Artigo em Inglês | MEDLINE | ID: mdl-36499284

RESUMO

Excited-State Intramolecular Photon Transfer (ESIPT) is known for the geometry-related phenolic and imine groups. The Schiff bases formed upon condensation of salicyl aldehyde and glycine led to the formation of ESIPT models. A series of alkali metal salicyliden glycinates were analyzed by X-ray diffraction of their monocrystals and spectroscopy measurements. The X-ray analysis revealed varied hydration levels between the salts. They adapted trans geometry on the imine groups and mostly anticlinal conformation with the neighboring atoms, which is different from the other structurally-related compounds in literature. Fluorescence of these compounds was found for the crystalline forms only. Protonation of the imine nitrogen atom and further proton distribution was consistent with the ESIPT theory, which also explained the observed fluorescence with the highest Stokes shift of 10,181 cm-1 and 10.1% of fluorescence quantum yield for the sodium salt.


Assuntos
Prótons , Bases de Schiff , Bases de Schiff/química , Conformação Molecular , Fótons , Fenômenos Químicos , Iminas
18.
Molecules ; 27(23)2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36500251

RESUMO

This article reports the synthesis, characterization, geometrical optimization, and biological studies of new MBH-based organometallic compounds of medicinal significance. The ligand (MNHA) was prepared via the Morita-Baylis-Hillman (MBH) synthetic route, from aromatic aldehyde containing multiple functional groups. Metal complexes were prepared in an alkaline medium and under other suitable reaction conditions. Spectral and elemental analyses were used to identify the structural and molecular formulas of each compound. Optimized geometry was determined through density functional theory (DFT) B3LYP and 6-311++ G (d,p) basis set for the MBH adduct, whereas structures of novel complexes were optimized with the semi-empirical PM6 method. Powder XRD analysis furnished the crystal class of complexes, with Co3+, Cr3+, and Mn2+ being cubic, while Ni2+ was hexagonal, and Cu2+ was orthorhombic. Moreover, the ligand, along with Ni2+ and Co3+ complexes, showed profound antibacterial action against S. aureus, E. coli, B. pumilis, and S. typhi. Additionally, all of the complexes were shown to persist in the positive antioxidant potential of the ligand. Contrarily, not a single metal complex conserved the antifungal potentials of the ligand.


Assuntos
Complexos de Coordenação , Staphylococcus aureus , Ligantes , Simulação de Acoplamento Molecular , Testes de Sensibilidade Microbiana , Escherichia coli , Complexos de Coordenação/química , Bases de Schiff/química
19.
Molecules ; 27(23)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36500309

RESUMO

A number of novel heteroligand Zn(II) complexes (1-8) of the general type (Ln)Zn(NN) containing O,N,O'-, O,N,S-donor redox-active Schiff bases and neutral N,N'-chelating ligands (NN) were synthesized. The target Schiff bases LnH2 were obtained as a result of the condensation of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with substituted o-aminophenols or o-aminothiophenol. These ligands with combination with 2,2'-bipyridine, 1,10-phenanthroline, and neocuproine are able to form stable complexes upon coordination with zinc(II) ion. The molecular structures of complexes 4∙H2O, 6, and 8 in crystal state were determined by means of single-crystal X-ray analysis. In the prepared complexes, the redox-active Schiff bases are in the form of doubly deprotonated dianions and act as chelating tridentate ligands. Complexes 6 and 8 possess a strongly distorted pentacoordinate geometry while 4∙H2O is hexacoordinate and contains water molecule coordinated to the central zinc atom. The electrochemical properties of zinc(II) complexes were studied by the cyclic voltammetry. For the studied complexes, O,N,O'- or O,N,S-donor Schiff base ligands are predominantly involved in electrochemical transformations in the anodic region, while the N,N'-coordinated neutral nitrogen donor ligands demonstrate the electrochemical activity in the cathode potential range. A feature of complexes 5 and 8 with sterically hindered tert-butyl groups is the possibility of the formation of relatively stable monocation and monoanion forms under electrochemical conditions. The values of the energy gap between the boundary redox orbitals were determined by electrochemical and spectral methods. The parameters obtained in the first case vary from 1.97 to 2.42 eV, while the optical bang gap reaches 2.87 eV.


Assuntos
Complexos de Coordenação , Bases de Schiff , Bases de Schiff/química , Cristalografia por Raios X , Estrutura Molecular , Zinco/química , Ligantes
20.
Molecules ; 27(23)2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-36500325

RESUMO

The four new complexes, [Cu(HL1)(L2)Cl] (1), [Cu(HL1)(L1)]∙Cl∙2H2O (2), [Co(L1)2]∙Cl (3) and [Cd(HL1)I2]∙dmso (4), have been prepared by one-pot reactions of the respective chloride or iodide metal salt with a non-aqueous solution of the polydentate Schiff base, HL1, resulted from in situ condensation of benzhydrazide and 2-pyridinecarboxaldehyde, while a ligand HL2, in case of 1, has been formed due to the oxidation of 2-pyridinecarboxaldehyde under reaction conditions. The crystallographic analysis revealed that the molecular building units in 1-4 are linked together into complex structures by hydrogen bonding, resulting in 1D, 2D and 3D supramolecular architectures for 1, 2 and 4, respectively, and the supramolecular trimer for 3. The electronic structures of 1-4 were investigated by the DFT theoretical calculations. The non-covalent interactions in the crystal structures of 1-4 were studied by means of the Hirshfeld surface analysis and the QTAIM theory with a special focus on the C-H⋯Cl bonding. From the DFT/DLPNO-CCSD(T) calculations, using a series of charged model {R3C-H}0⋯Cl- assemblies, we propose linear regressions for assessment of the interaction enthalpy (ΔH, kcal mol-1) and the binding energy (BE, kcal mol-1) between {R3C-H}0 and Cl- sites starting from the electron density at the bond critical point (ρ(rBCP), a.u.): ΔH = -678 × ρ(r) + 3 and BE = -726 × ρ(r) + 4. It was also has been found that compounds 1, 3 and 4 during in vitro screening showed an antibacterial activity toward the nine bacteria species, comprising both Gram-positive and Gram-negative, with MIC values ranging from 156.2 to 625 mg/L. The best results have been obtained against Acinetobacter baumannii MßL.


Assuntos
Complexos de Coordenação , Bases de Schiff , Bases de Schiff/química , Ligantes , Cádmio , Antibacterianos/farmacologia , Antibacterianos/química , Bactérias , Cobre/química , Complexos de Coordenação/farmacologia , Complexos de Coordenação/química
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