scholarly journals SYNTHESIS, SPECTRAL CHARACTERIZATION AND ANTIMICROBIAL ACTIVITIES OF BIS(CYCLOPENTADIENYL)TITANIUM(IV) COMPLEXES WITH SCHIFF BASES DERIVED FROM5-(SUBSTITUTED ARYL)-2-HYDRAZINO-1, 3, 4-OXADIAZOLE AND INDOLINE-2, 3-DIONE

2021 ◽  
Vol 9 (09) ◽  
pp. 900-909
Author(s):  
Anupama Srivastava ◽  
◽  
Shilpi Srivastava ◽  
Om. P. Pandey ◽  
Soumitra K. Sengupta ◽  
...  

Titanium(IV) complexes of type[(η5-C5H5)2TiCl(L)] have been synthesized by the reactions of bis(cyclopentadienyl)titanium(IV)dichloride with Schiff bases (LH) derived by the condensation of 5-(substituted aryl)-2-hydrazino-1,3,4-oxadiazole and indoline-2,3-dione in tetrahydrofuranin the presence oftriethylamine. All these complexes are soluble in PhNO2, DMF and DMSO.The complexes were characterized by elemental analyses, electrical conductance, magnetic susceptibility, UV-Vis, IR, 1H NMR, 13C NMR, XRD and SEM spectral techniques. Low molar conductance values indicate that they are non-electrolytes. The spectral data indicate5-coordinate geometry for the complexes.XRD pattern indicate that the complexes have monoclinic crystal system and particle sizes were found 49.36 nm (nano-size). In vitro antifungal activity of synthesized compounds was evaluated against fungi Aspergillusniger, Aspergillusflavus,ColletotrichumfalcatumandIn vitro antibacterial activity was determined by screening the compounds against gram negative (P. aeruginosa, S.typhi) and gram positive (S. aureus and B.subtilis) bacterial strains using minimum inhibition concentration method (MIC) by serial dilution technique. The titanocene(IV) complexes have higher antimicrobial effect than the parent Schiff bases.

2021 ◽  
Vol 37 (5) ◽  
pp. 1146-1151
Author(s):  
Suman Kumari ◽  
Shobhana Sharma ◽  
Seema Seema ◽  
Poonam Yadav ◽  
Mamta Ranka

In our present research work, we have synthesized two ternary metal complexes of Mn(II), complex-I as [Mn(L)(Gly)(Cl)(H2O)] and complex-II as [Mn(L)(Q)(Cl)(H2O)]; where L is Isatinphenylhydrazone (IPH) as primary ligand, whereas glycine (Gly) and 8-hydroxyquinoline (HQ) as secondary ligand in complex-I and II respectively, in 1:1:1 (M : L : Gly or M : L : Q) molar ratios. Above synthesized complexes are employed for characterization using various analytical techniques including elemental analysis, melting point determination, magnetic moment measurements, molar conductance measurements, and spectral techniques (FTIR, UV, 1H NMR) etc. Further, their antimicrobial activities were evaluated against selected bacterial strains i.e., B. subtilis, S. aureus (Gram positive) and P. aeruginosa, E. coli (Gram negative) and fungal strains (T. reesei, A. niger, C. albicans) and found significantly active.


2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
K. Savithri ◽  
B. C. Vasantha Kumar ◽  
H. K. Vivek ◽  
H. D. Revanasiddappa

A bidentate (N- and O-) imine-based ligand (L1) and its metal complexes of types [CuII(L1)2] (C1), [CuII(L1)(Phen)] (C2), [CoIII(L1)2] (C3), and [CoIII(L1)(Phen)] (C4) (L1 = 2-((E)-(6-fluorobenzo[d]thiazol-2-ylimino)methyl)-4-chlorophenol and phen = 1,10-phenanthroline) were synthesized as potential chemotherapeutic drug candidates. The prepared complexes were structurally characterized by spectral techniques (NMR, FT-IR, LC-MS, EPR, and electronic absorption), thermogravimetric analysis (TGA/DTA), magnetic moment, and CHNO elemental analysis. Spectroscopic studies suggested the distorted octahedral structure for all complexes. In vitro bioassay studies include binding and nuclease activities of the ligand and its complexes with target calf thymus- (CT-) DNA were carried out by employing UV-Vis, fluorescence spectroscopy, viscosity, and gel electrophoresis techniques. The extent of binding propensity was determined quantitatively by Kb and Ksv values which revealed a higher binding affinity for C2 and C4 as compared to C1 and C3. In addition, the scavenging superoxide anion free radical (O∙-2) activity of metal complexes was determined by nitroblue tetrazolium (NBT) light reduction assay. Molecular docking studies with DNA and SOD enzyme were also carried out on these compounds. The antimicrobial study has shown that all the compounds are potential antibacterial agents against Gram-negative bacterial strains and better antifungal agents with respect to standard drugs used.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Kiran Singh ◽  
Parvesh Puri ◽  
Yogender Kumar ◽  
Chetan Sharma

This paper deals with the syntheses and structural features of some new diorganosilicon(IV) and diorganotin(IV) complexes having general formulae (CH3)2MCl(L1), (CH3)2MCl(L2), (CH3)2M(L1)2, and (CH3)2M(L2)2 with new Schiff bases (M = Si and Sn). The Schiff bases HL1 and HL2 have been derived from the condensation of 3-bromobenzaldehyde with 4-amino-3-ethyl-5-mercapto-1,2,4-triazole and 4-amino-5-mercapto-3-propyl-1,2,4-triazole, respectively. The compounds have been characterized by the elemental analyses, molar conductance, and spectral (UV, IR, 1H, 13C, 29Si, and 119Sn NMR) studies. The resulting complexes have been proposed to have trigonal bipyramidal and octahedral geometries. In vitro antimicrobial activities of the compounds have been carried out.


2021 ◽  
Vol 34 (1) ◽  
pp. 183-190
Author(s):  
Mahak Dalal ◽  
Manish Kumar ◽  
K.K. Verma ◽  
Sapana Garg

This article reports the synthesis, characterization and antimicrobial screening of a tridentate 2-[(2-hydroxyphenyl)imino methyl]-1-naphthol ligand (H2AP) and its organotellurium(IV) complexes. Structural characterization of the synthesized ligand and complexes was confirmed by using FT-IR, 1H NMR, 13C NMR, UV-vis, mass spectrometry, molar conductance and elemental analysis. Geometry of all the synthesized compounds has been optimized and their DFT based chemical reactivity descriptors were calculated. DFT and spectral data studies revealed distorted square pyramidal geometry for the tellurium(IV) complexes. In vitro antimicrobial activities of the synthesized ligand and its tellurium(IV)complexes were evaluated against two Gram-positive, two Gram-negative bacterial strains and three fungal strains. The tellurium(IV) complexes exhibited promising activity as compared to the Schiff base ligand.


2010 ◽  
Vol 75 (2) ◽  
pp. 217-228 ◽  
Author(s):  
Dharmpal Singh ◽  
Krishan Kumar ◽  
Ramesh Kumar ◽  
Jitender Singh

A novel series of complexes of the type [M(C28H24N4)X2], where M = Co(II), Ni(II), Cu(II), Zn(II) and Cd(II), X = Cl-, NO3 -, CH3COO- and (C28H24N4) corresponds to the tetradentate macrocyclic ligand, were synthesized by template condensation of 1,8-diaminonaphthalene and diacetyl in the presence of divalent metal salts in methanolic medium. The complexes were characterized by elemental analyses, conductance and magnetic measurements, as well as by UV/Vis, NMR, IR and MS spectroscopy. The low values of the molar conductance indicate non-electrolyte type of complexes. Based on these spectral data, a distorted octahedral geometry may be proposed for all of these complexes. All the synthesized macrocyclic complexes were tested for in vitro antibacterial activity against some pathogenic bacterial strains, viz Bacillus cereus, Salmonella typhi, Escherichia coli and Staphylococcus aureus. The MIC values shown by the complexes against these bacterial strains were compared with the MIC shown by the standard antibiotics linezolid and cefaclor.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 703
Author(s):  
Severino Zara ◽  
Giacomo L. Petretto ◽  
Alberto Mannu ◽  
Giacomo Zara ◽  
Marilena Budroni ◽  
...  

The production of saffron spice generates large quantities of plant by-products: over 90% of the plant material collected is discarded, and a consideration fraction of this waste is plant stamens. This work investigated the chemical composition and the antimicrobial activities of the non-polar fraction extracted from four different saffron flower stamens. The chemical composition of ethereal extracts of the saffron stamens was qualitatively assessed by means of gas–chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) analyses. These analyses revealed ethereal extracts to possess a high polyunsaturated fatty acid content. In vitro antibacterial activity of stamen extracts showed no large differences between Gram-positive and Gram-negative bacteria in terms of minimal inhibitory concentration (MIC). In food matrix microbial analysis of the bacterial strains belonging to the main foodborne pathogen species, including Staphylococcus aureus DSM 20231, Escherichia coli DSM 30083, and Listeria monocytogenes DSM 20600, using low-fat UHT milk, revealed a statistically significant reduction in the number of cells (particularly for E. coli and S. aureus with a complete elimination of the population of the two target bacteria following incubation in diethyl ether extracts of saffron stamen (DES) at high concentrations tested, both at 37 °C and 6 °C (for 48 h and 7 days, respectively). A synergic effect was observed when the pathogens were incubated at 6 °C with DES. This work shows these by-products to be excellent sources of bioactive compounds, which could be exploited in high-added-value products, such as food, cosmetics, and drugs.


2021 ◽  
Vol 11 (9) ◽  
pp. 4315
Author(s):  
Emanuel Vamanu ◽  
Laura Dorina Dinu ◽  
Cristina Mihaela Luntraru ◽  
Alexandru Suciu

Bioactive compounds and phenolic compounds are viable alternatives to antibiotics in recurrent urinary tract infections. This study aimed to use a natural functional product, based on the bioactive compounds’ composition, to inhibit the uropathogenic strains of Escherichia coli. E. coli ATCC 25922 was used to characterize the IVCM (new in vitro catheterization model). As support for reducing bacterial proliferation, the cytotoxicity against a strain of Candida albicans was also determined (over 75% at 1 mg/mL). The results were correlated with the analysis of the distribution of biologically active compounds (trans-ferulic acid-268.44 ± 0.001 mg/100 g extract and an equal quantity of Trans-p-coumaric acid and rosmarinic acid). A pronounced inhibitory effect against the uropathogenic strain E. coli 317 (4 log copy no./mL after 72 h) was determined. The results showed a targeted response to the product for tested bacterial strains. The importance of research resulted from the easy and fast characterization of the functional product with antimicrobial effect against uropathogenic strains of E. coli. This study demonstrated that the proposed in vitro model was a valuable tool for assessing urinary tract infections with E. coli.


2020 ◽  
Vol 41 (1) ◽  
pp. 26-35
Author(s):  
Kishor Devkota ◽  
Govinda Pathak ◽  
Bhushan Shakya

Triazole ring system has attracted a continuously growing interest of synthetic organic chemists and those dealing with the medicinal compounds due to its versatile potential to interact with biological systems. Schiff bases are also considered as one of the most biologically active compounds.  The aim of the present study was to synthesize new Schiff bases bearing triazole nucleus and to assess their antimicrobial activities. Four new Schiff base derivatives of 1,2,4-triazole-3-thione were synthesized by combining two different pharmacophores viz. triazole nucleus and Schiff base moiety and were characterized by spectral techniques (UV, FT-IR, and NMR). The Schiff bases were evaluated for antibacterial (Staphylococcus aureus, Escherichia coli, and Klebsiella pneumoniae) and antifungal (Candida albicans) activities. The synthesized compounds exhibited good to moderate activities against different strains of bacteria and fungi tested.


2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Agata Cieślik-Bielecka ◽  
Tadeusz Bold ◽  
Grzegorz Ziółkowski ◽  
Marcin Pierchała ◽  
Aleksandra Królikowska ◽  
...  

The aim of the study was to investigate the leukocyte- and platelet-rich plasma (L-PRP) antimicrobial activity. The studied sample comprised 20 healthy males. The L-PRP gel, liquid L-PRP, and thrombin samples were testedin vitrofor their antibacterial properties against selected bacterial strains using the Kirby-Bauer disc diffusion method. Two types of thrombin were used (autologous and bovine). Zones of inhibition produced by L-PRP ranged between 6 and 18 mm in diameter. L-PRP inhibited the growth ofStaphylococcus aureus(MRSA and MSSA strains) and was also active againstEnterococcus faecalisandPseudomonas aeruginosa. There was no activity againstEscherichia coliandKlebsiella pneumoniae. The statistically significant increase of L-PRP antimicrobial effect was noted with the use of major volume of thrombin as an activator. Additionally, in groups where a bovine thrombin mixture was added to L-PRP the zones of inhibition concerning MRSA,Enterococcus faecalis, andPseudomonas aeruginosawere larger than in the groups with autologous thrombin. Based on the conducted studies, it can be determined that L-PRP can evokein vitroantimicrobial effects and might be used to treat selected infections in the clinical field. The major volume of thrombin as an activator increases the strength of the L-PRP antimicrobial effect.


Marine Drugs ◽  
2018 ◽  
Vol 16 (12) ◽  
pp. 466 ◽  
Author(s):  
Mariana Marggraf ◽  
Pavel Panteleev ◽  
Anna Emelianova ◽  
Maxim Sorokin ◽  
Ilia Bolosov ◽  
...  

Biological activity of the new antimicrobial peptide polyphemusin III from the horseshoe crab Limulus polyphemus was examined against bacterial strains and human cancer, transformed, and normal cell cultures. Polyphemusin III has the amino acid sequence RRGCFRVCYRGFCFQRCR and is homologous to other β-hairpin peptides from the horseshoe crab. Antimicrobial activity of the peptide was evaluated and MIC (minimal inhibitory concentration) values were determined. IC50 (half-maximal inhibitory concentration) values measured toward human cells revealed that polyphemusin III showed a potent cytotoxic activity at concentrations of <10 μM. Polyphemusin III caused fast permeabilization of the cytoplasmic membrane of human leukemia cells HL-60, which was measured with trypan blue exclusion assay and lactate dehydrogenase-release assay. Flow cytometry experiments for annexin V-FITC/ propidium iodide double staining revealed that the caspase inhibitor, Z-VAD-FMK, did not abrogate disruption of the plasma membrane by polyphemusin III. Our data suggest that polyphemusin III disrupts the plasma membrane integrity and induces cell death that is apparently not related to apoptosis. In comparison to known polyphemusins and tachyplesins, polyphemusin III demonstrates a similar or lower antimicrobial effect, but significantly higher cytotoxicity against human cancer and transformed cells in vitro.


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