The antibacterial and antifungal activities of three schiff bases were evaluated against some pathogenic bacteria and fungi. Parallel experiments were also carried out with standard drugs (Kanamycin for bacteria and Nystatin for fungi). Two compounds [N-(1-phenyl-2-hydroxy-2phenylethylidine)-2',4' dinitrophenyl hydrazine, abbreviated as PDH and N-(2-hydroxy benzylidine)-2'-hydroxy imine, abbreviated as HHP] showed significant antimicrobial activities. The rest one [N-(1-phenyl 2-hydroxy-2 phenyl ethylidine) 2'-hydroxy phenyl imine, abbreviated as PHP] showed moderate activity. All these three compounds were found to possess pronounced cytotoxic effect. These compounds can be considered as potent antimicrobial agents.
Aldehydes ; Anti-Infective Agents ; Bacteria ; Benzoin ; Fungi ; Hydrazines ; Nystatin ; Schiff Bases

It was found that psoralen derivative could perform a Friedel-Crafts acylation smoothly with acetic anhydride to give 5'-acetylpsoralen in a 73% yield. In the presence of boron trifluoride etherate, 5'-acetylpsoralen reacted with both aromatic amines and aliphatic amine smoothly to afford 5'-Schiff-base group substituted psoralen derivatives in 72%-92% yields. The novel synthetic method has the advantages of cheap materials, mild reaction conditions, good yields and high regioselectivity in the Friedel-Crafts acylation. Cell viability assay by MTT demonstrates that some of the psoralen derivatives 6 have antiproliferative activities.
Acylation ; Boranes ; chemistry ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Furocoumarins ; chemical synthesis ; chemistry ; pharmacology ; Humans ; Molecular Structure ; Schiff Bases ; chemistry

OBJECTIVETo establish the antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand L.

METHODS(N, N'-bis (1-naphthaldimine)-o-phenylenediamine) was prepared from the condensation of 2-hydroxy-1-naphthaldehyde with o-phenylenediamine in a molar ratio of 2:1. The antimicrobial activity of the resultant Ln (III) complexes was investigated using agar well diffusion and micro-broth dilution techniques; the latter was used to establish the minimum inhibitory concentrations for each compound investigated.

RESULTSMost of Ln (III) complexes were found to exhibit antibacterial activities against a number of pathogenic bacteria with MICs ranging between 1.95-250.00 µg/mL. Staphylococcus aureus was the most susceptible bacterial species to [LaL(NO3)2(H2O)](NO3) complex while Shigella dysenteriae and Escherichia coli required a relatively higher MIC (250 µg/mL). The complexes La (III) and Pr (III) were effective inhibitors against Staphylococcus aureus, whereas Sm (III) complex was effective against Serratia marcescens. On the other hand, Gd (III), La (III) and Nd (III) were found to be more potent inhibitors against Pseudomonas aeruginosa than two of commonly used antibiotics. The remaining Ln (III) complexes showed no remarkable activity as compared to the two standard drugs used.

CONCLUSIONSTetradentate Schiff base ligand L and its complexes could be a potential antibacterial compounds after further investigation.

Anti-Bacterial Agents ; chemistry ; pharmacology ; Bacteria ; drug effects ; Disk Diffusion Antimicrobial Tests ; Lanthanoid Series Elements ; chemistry ; pharmacology ; Ligands ; Microbial Sensitivity Tests ; Schiff Bases ; chemistry

OBJECTIVEA series of 2-benzylideneaminonaphthothiazoles were designed and synthesized incorporating the lipophilic naphthalene ring to render them more capable of penetrating various biomembranes.

METHODSSchiff bases were synthesized by the reaction of naphtha[1,2-d]thiazol-2-amine with various substituted aromatic aldehydes. 2-(2'-Hydroxy)benzylideneaminonaphthothiazole was converted to its Co(II), Ni(II) and Cu(II) metal complexes upon treatment with metal salts in ethanol. All the compounds were evaluated for their antibacterial activities by paper disc diffusion method with Gram positive Staphylococcus aureus and Staphylococcus epidermidis and Gram negative Escherichia coli and Pseudomonas aeruginosa bacteria. The minimum inhibitory concentrations of all the Schiff bases and metal complexes were determined by agar streak dilution method.

RESULTSAll the compounds moderately inhibited the growth of Gram positive and Gram negative bacteria. In the present study among all Schiff bases 2-(2'-hydroxy)benzylideneaminonaphthothiazole showed maximum inhibitory activity and among metal complexes Cu(II) metal complex was found to be most potent.

CONCLUSIONThe results obtained validate the hypothesis that Schiff bases having substitution with halogens, hydroxyl group and nitro group at phenyl ring are required for the antibacterial activity while methoxy group at different positions in the aromatic ring has minimal role in the inhibitory activity. The results also indicated that the metal complexes are better antibacterial agents as compared to the Schiff bases.

Amines ; chemical synthesis ; pharmacology ; Anti-Bacterial Agents ; chemical synthesis ; chemistry ; pharmacology ; Cobalt ; Copper ; Nickel ; Schiff Bases ; Structure-Activity Relationship ; Thiazoles ; chemical synthesis ; pharmacology

To discover a novel antitumor lead compound derived from fluoroquinolone, C3 carboxyl group of ciprofloxacin (1) was replaced with heterocyclic ring to form cyclopropyl fluoroquinolone aminothiadiazole scaffold (2), then reacted with aromatic aldehydes to give the Schiff bases compounds (3a-3j). The structures of new compounds were characterized by element analysis and spectral data, and their in vitro antitumor activity against SMMC-7721, HL60 and L1210 cell lines was evaluated by MTT assay via the respective IC50 values. The bioactive assay showed that eleven thiadiazole-substituted ciprofloxacin derivatives displayed potential cytotoxicity against the tested cancer cell lines, where the IC50 values of compounds 3d and 3f reached micromolar concentration. Therefore, the C3 carboxyl group of fluoroquinolone is not necessary to antitumor activity. Functionally modified heterocycle-substituted fluoroquinolone as potent antitumor lead compound is valuable for further study.
Animals ; Antineoplastic Agents ; chemical synthesis ; pharmacology ; Cell Line, Tumor ; drug effects ; Ciprofloxacin ; analogs & derivatives ; chemical synthesis ; pharmacology ; Drug Screening Assays, Antitumor ; HL-60 Cells ; Humans ; Inhibitory Concentration 50 ; Leukemia L1210 ; pathology ; Liver Neoplasms ; pathology ; Schiff Bases ; chemical synthesis ; pharmacology

To find out a novel lead compound from heterocyclic amine Schiff bases for developing new antitumor agents, each of (4-amino-5-substituted-s-triazol-3-ylthio) -acetic acids 2a-j was condensed with anthracene-9-carbaldehyde to obtain Schiff-bases of [4-(anthracen-9-yl methylene) amino] -5-substituted-s-triazol-3-ylsulfanyl] -acetic acids 3a-j. The structures of new compounds synthesized were characterized by elemental analysis and spectral data, and in vitro antitumor activity was also evaluated against CHO, HL60 and L1210 cell lines by MTT assay.
Acetic Acid ; chemistry ; Animals ; Anthracenes ; chemistry ; Antineoplastic Agents ; chemical synthesis ; chemistry ; pharmacology ; CHO Cells ; Cricetinae ; Cricetulus ; HL-60 Cells ; Humans ; Leukemia L1210 ; pathology ; Mice ; Molecular Structure ; Schiff Bases ; chemical synthesis ; chemistry ; pharmacology ; Triazoles ; chemical synthesis ; chemistry ; pharmacology

To explore novel coumarin derivatives with more potent anti-proliferative activity, a series of novel compounds were designed and synthesized by linking Schiff base and N, N-bis (2-chloroethyl) amine pharmacophore of nitrogen mustards to the coumarin's framework. Their structures were confirmed by 1H NMR, MS and element analysis techniques. In vitro anti-proliferative activities were evaluated against HepG2, DU145 and MCF7 cell lines by the standard MTT assay. The results showed that some of the target compounds exhibited strong anti-proliferative activities against selected tumor cells, and compounds 7c, 7f, 7g, 7h and 7q were better than or equal to the activities of positive control, they deserved further development.
Antineoplastic Agents ; chemical synthesis ; pharmacology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Coumarins ; chemical synthesis ; pharmacology ; Drug Design ; Drug Screening Assays, Antitumor ; Humans ; Nitrogen Mustard Compounds ; chemical synthesis ; pharmacology ; Schiff Bases ; Structure-Activity Relationship

Alzheimer's disease (AD) is a progressive neurodegenerative disease endangering human health seriously. Recent reports have revealed that beta-amyloid aggregates play a key role in the pathogenesis of AD. Thus, targeting the Abeta plaques benzothiazole derivatives were synthesized with the scaffold of the most promising imaging agent PIB ([11C]-6-OH-BTA-1, [11C]-2-(4-(methylamino)phenyl)-6-hydroxybenzothiazole) and C = N as linker to study the binding characteristics with the target protein through surface plasmon resonance (SPR) technique. These derivatives were synthesized through simple yet effective method with high yields and characterized by 1H NMR and FTIR. The binding properties (K(D)) were determined with Biacore X-100 instrument according to the fitting-plot curve. Compounds 3a and 3f showed high binding affinity for Abeta1-40. The results suggest that benzothiazole derivatives could be served as a scaffold to develop novel beta-amyloid imaging agents for the diagnosis of AD.
Alzheimer Disease ; diagnosis ; Amyloid beta-Peptides ; chemistry ; Aniline Compounds ; chemistry ; Benzothiazoles ; chemical synthesis ; chemistry ; Humans ; Peptide Fragments ; chemistry ; Protein Binding ; Schiff Bases ; chemical synthesis ; chemistry ; Surface Plasmon Resonance ; Thiazoles ; chemistry

The complexes of tailor made ligands with life essential metal ions may be an emerging area to answer the problems of multi drug resistance. The coordination complexes of VO(II), Co(II), Ni(II) and Cu(II) with the Schiff bases derived from isatin with 3-chloro-4-floroaniline and 2-pyridinecarboxaldehyde with 4-aminoantipyrine have been synthesized by conventional as well as microwave methods. These compounds have been characterized by elemental analysis, molar conductance, electronic spectra, FT-IR, FAB mass and magnetic susceptibility measurements. FAB mass data show degradation of complexes. Both the ligands behave as bidentate and tridentate coordinating through O and N donor. The complexes exhibit coordination number 4, 5 or 6. The Schiff base and metal complexes show a good activity against the bacteria; Staphylococcus aureus, Escherichia coli and Streptococcus fecalis and fungi Aspergillus niger, Trichoderma polysporum, Candida albicans and Aspergillus flavus. The antimicrobial results also indicate that the metal complexes are better antimicrobial agents as compared to the Schiff bases. The minimum inhibitory concentrations of the metal complexes were found in the range 10~40 microg/mL.
Ampyrone ; Anti-Infective Agents ; Aspergillus flavus ; Aspergillus niger ; Candida albicans ; Coordination Complexes ; Drug Resistance ; Electronics ; Electrons ; Escherichia coli ; Fungi ; Humans ; Ions ; Isatin ; Ligands ; Magnetics ; Magnets ; Microbial Sensitivity Tests ; Microwaves ; Molar ; Pyridines ; Schiff Bases ; Staphylococcus aureus ; Streptococcus ; Tissue Donors ; Trichoderma

Two Schiff base ligands L1 and L2 were obtained by the condensation of glycylglycine respectively with imidazole-2-carboxaldehyde and indole-3-carboxaldehyde and their complexes with Zn(II) were prepared and characterized by microanalytical, conductivity measurement, IR, UV-Vis., XRD and SEM. The molar conductance measurement indicates that the Zn(II) complexes are 1 : 1 electrolytes. The IR data demonstrate the tetradentate binding of L1 and tridentate binding of L2. The XRD data show that Zn(II) complexes with L1 and L2 have the crystallite sizes of 53 and 61 nm respectively. The surface morphology of the complexes was studied using SEM. The in vitro biological screening effects of the investigated compounds were tested against the bacterial species Staphylococcus aureus, Escherichia coli, Klebsiella pneumaniae, Proteus vulgaris and Pseudomonas aeruginosa and fungal species Aspergillus niger, Rhizopus stolonifer, Aspergillus flavus, Rhizoctonia bataicola and Candida albicans by the disc diffusion method. A comparative study of inhibition values of the Schiff base ligands and their complexes indicates that the complexes exhibit higher antimicrobial activity than the free ligands. Zinc ions are proven to be essential for the growth-inhibitor effect. The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium.
Aspergillus flavus ; Aspergillus niger ; Cell Count ; Diffusion ; Electrolytes ; Escherichia coli ; Glycylglycine ; Indoles ; Ions ; Klebsiella ; Ligands ; Mass Screening ; Molar ; Proteus vulgaris ; Pseudomonas aeruginosa ; Rhizoctonia ; Rhizopus ; Schiff Bases ; Staphylococcus aureus ; Zinc