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1.  Synthesis, Characterization, and Cytotoxic Activity of New Lanthanum(III) Complexes of Bis-Coumarins 
Complexes of lanthanum(III) with bis-coumarins: 3,3′-benzylidene-bis(4-hydroxy-2H-1-benzopyran-2-one) (H2L1) and bis(4-hydroxy-2-oxo-2H-chromen-3-yl)-(1H-pyrazol-3-yl)-methane (H2L2) were synthesized by reaction of lanthanum(III) salt and the ligands, in amounts equal to metal : ligand molar ratio of 1 : 2. The complexes were prepared by adding an aqueous solution of lanthanum(III) salt to an aqueous solution of the ligand subsequently raising the pH of the mixture gradually to circa 5.0 by adding dilute solution of sodium hydroxide. The lanthanum(III) complexes with bis-coumarins were characterized by different physicochemical methods—elemental analysis, IR-, 1H-, and 13C-NMR-spectroscopies, and mass spectral data. The spectral data of lanthanum(III) complexes were interpreted on the basis of comparison with the spectra of the free ligands. This analysis showed that in the La(III) complexes, the ligands coordinated to the metal ion through both deprotonated hydroxyl groups. On the basis of the ν(C=O) red shift observed, participation of the carbonyl groups in the coordination with the metal ion was also suggested. In the present study, we performed a cytotoxic-effects screening of the lanthanum complexes with H2L1 and H2L2 in a panel of human tumor cell lines, using the standard MTT-dye reduction assay for cell viability. The panel consisted of the acute myeloid leukemia-derived HL-60 and the chronic myeloid leukemia-derived BV-173. Following a 24- hour treatment of BV-173 cells with lanthanum complex of H2L1 at 100 or 200 μM led to a DNA-laddering. The findings suggest that the observed cytotoxicity of the lanthanum complex of H2L1 on BV-173 is at least partly mediated through induction of programmed cell death.
PMCID: PMC1686302  PMID: 17497005
2.  Synthesis, Spectral, and Biological Properties of Copper(II) Complexes of Thiosemicarbazones of Schiff Bases Derived from 4-Aminoantipyrine and Aromatic Aldehydes 
We have synthesized a novel series of Schiff bases by condensation of 4-aminoantipyrine and various aromatic aldehydes followed by reaction with thiosemicarbazide. These thiosemicarbazones are potential ligands toward transition metal ions. The reaction of copper(II) salts with 4[N-(benzalidene)amino]antipyrinethiosemicarbazone (BAAPTS), 4[N-(4′-methoxybenzalidene) amino] antipyrinethiosemicarbozone (MBAAPTS), 4[N-(4′-dimethylamino benzalidene) amino] antipyrinethiosemicarbazone (DABAAPTS), and 4[N-(cinnamalidene) amino] antipyrinethiosemicarbazone (CAAPTS) resulted in the formation of solid complexes with the general composition CuX2 · (H2O)(L)(X = Cl, Br,NO3,NCS, or CH3COO; L = BAAPTS, MBAAPTS, DABAAPTS, or CAAPTS). These complexes were characterized through elemental analysis, molecular weight, electrical conductance, infrared, electronic spectra, and magnetic susceptibilities at room temperature. Copper(II) complexes with BAAPTS and MBAAPTS were screened for antibacterial and antifungal properties and have exhibited potential activity. Thermal stabilities of two representative complexes were also investigated.
PMCID: PMC1686301  PMID: 17497009
3.  Assessment of Toxicity of Some Penta- and Hexacoordinated Organotin(IV) and Tetracoordinated Tin(II) Complexes of Heterocyclic β-Diketones 
A number of penta- and hexacoordinated organotin(IV) complexes and tetracoordinated tin(II) complexes of compositions Me2SnCl[RCOC:CON(C6H5)N:C⎴CH3] (where R = − CH3, −p−ClC6H4, and −C6H5), Me2Sn[RCOC:CON(C6H5)N:C⎴CH3]2 (where R = −CH3, and −C6H5), and Sn(II) [RCOC:CON(C6H5)N:C⎴CH3]2 (where R = −p−ClC6H4 and −C6H5) were screened for their toxicity against Musca domestica (house fly). In general, organotin(IV) complexes contribute more to the activity than tin(II) complexes.
PMCID: PMC1686300  PMID: 17497010
4.  Antispermatogenic Activity of the Benzothiazoline Ligand and Corresponding Organoantimony(V) Derivative in Male Albino Rats 
Triphenylantimony(V) derivative, Ph3Sb(OPri) [SC6H4N : C(CH3)CH2C(O)CH3], 1b, and the corresponding benzothiazoline ligand [1, 2], HNC6H4SC⎴(CH3)CH2C(O)CH3, 1a, have been tested for their effects on the reproductive system of male albino rats. The oral administration of both 1a and 1b at the dose level of 10 mg/rat/day produced significant reduction in the weights of testes, epididymides, seminal vesicles, and ventral prostate. Significant decrease in sperm motility as well as in sperm density resulted in 100% sterility. Significant (P < .01) alterations were also found in biochemical parameters of reproductive organs in treated male rats as compared to the control group. Production of preleptotene, pachytene, and secondary spermatocytes was decreased by 42%, 43%, 39%, and by 44%, 49%, 55% in the ligand, 1a, and organoantimony(V) derivative, 1b, treated rats, respectively. These results indicate that both compounds 1a and 1b are antispermatogenic in nature and on oral administration in male rats, and finally caused sterility. A comparison indicates that the organoantimony(V) derivative 1b is more effective pertaining to its antispermatogenic activity than the corresponding ligand 1a.
PMCID: PMC1686299  PMID: 17496999
5.  Synthesis, Biological, Spectral, and Thermal Investigations of Cobalt(II) and Nickel(II) Complexes of N-Isonicotinamido -2′,4′-Dichlorobenzalaldimine 
A new series of 12 complexes of cobalt(II) and nickel(II) with N-isonicotinamido-2′,4′-dichlorobenzalaldimine (INH-DCB) with the general composition MX2 · n(INH-DCB) [M = Co(II) or Ni(II), X = Cl− ,Br−, NO3−, NCS−, or CH3COO−, n = 2; X = ClO4−, n = 3] have been synthesized. The nature of bonding and the stereochemistry of the complexes have been deduced from elemental analyses, infrared, electronic spectra, magnetic susceptibility, and conductivity measurements. An octahedral geometry has been suggested for all the complexes. The metal complexes were screened for their antifungal and antibacterial activities on different species of pathogenic fungi and bacteria and their biopotency has been discussed.
PMCID: PMC1686298  PMID: 17497006
6.  Fertility Regulation in Male Rats by Implemented Tetraazamacrocyclic Compounds of Iron(II): Synthetic, Spectroscopic, and Applied Aspects With Toxicological Screening 
Antifertility and histopathological investigations were carried out on reproductive organs of male albino rats induced by tetraazamacrocyclic complexes of iron(II). The complexes were synthesized by the template condensation of 1,2-diaminoethane, 1,3-diaminopropane with succinic acid and phthalic acid in 2 : 2 molar ratios which are abbreviated as [Fe(TAMLn)OAc] (n = 1 or 2 and TAMLn represents tetraazamacrocyclic ligand). The complexes have been characterized by elemental analysis, conductivity measurements, IR, and electronic spectra.
PMCID: PMC1686297  PMID: 17497000
7.  Effect of Benzothiazoline Ligand and Corresponding Organoantimony(V) Derivative on the Reproductive System of Male Rats 
Benzothiazoline HNC6H4SC⎴(C6H5)CH:C(OH)COOCH3 1 prepared by the condensation reaction of aroyl pyruvate and 2-aminothiophenol has been treated with Ph3Sb(OPri)2 to yield Ph3Sb[SC6H4NC(C6H5)CH:CO⎴COOCH3] 2. These compounds have been characterized by elemental analyses and molecular weight determinations. The probable structures of the ligand as well as antimony complex have been tentatively proposed on the basis of IR and NMR (1H and 13C) spectral evidences. Both compounds have been tested for their antifertility activity in male albino rats. The oral administration of compounds 1 and 2 at the dose level of 10 mg/rat/day significantly reduced the weights of testes, epididymides, ventral prostate, and seminal vesicles. The production of preleptotene spermatocytes was decreased by 36.57%; 57.23%, pachytene spermatocytes by 40.06%; 62.01%, and secondary spermatocytes by 52.45%; 63.22%, following the treatment of compounds 1 and 2, respectively. The marked reduction in sperm motility and density resulted in infertility by 100%. Significant (P < .01) alterations were found in biochemical parameters of reproductive organs in treated animals as compared to control group. It is concluded that all these effects may finally impair the fertility of male rats.
PMCID: PMC1686296  PMID: 17497001
8.  Synthetic, Structural, and Biochemical Studies of Organotin(IV) With Schiff Bases Having Nitrogen and Sulphur Donor Ligands 
Three bidentate Schiff bases having nitrogen and sulphur donor sequences were prepared by condensing S-benzyldithiocarbazate (NH2NHCS2CH2C6H5) with heterocyclic aldehydes. The reaction of diphenyltin dichloride with Schiff bases leads to the formation of a new series of organotin(IV) complexes. An attempt has been made to prove their structures on the basis of elemental analyses, conductance measurements, molecular weights determinations, UV, infrared, and multinuclear magnetic resonance (1H, 13C, and 119Sn) spectral studies. Organotin(IV) complexes were five- and six-coordinate. Schiff bases and their corresponding organotin complexes have also been screened for their antibacterial and antifungal activities and found to be quite active in this respect.
PMCID: PMC1686295  PMID: 17497003
9.  New Dihydro OO′Bis(Salicylidene) 2,2′ Aminobenzothiazolyl Borate Complexes: Kinetic and Voltammetric Studies of Dimethyltin Copper Complex with Guanine, Adenine, and Calf Thymus DNA 
The newly synthesized ligand, dihydro OO′bis(salicylidene) 2,2′ aminobenzothiazolyl borate (2), was derived from the reaction of Schiff base of 2-aminobenzothiazole and salicylaldehyde with KBH4. CuII (3) and ZnII (4) complexes of (2) were synthesized and further metallated with dimethyltindichloride to yield heterobimetallic complexes (5) and (6). All complexes have been thoroughly characterized by elemental analysis, and IR, NMR, EPR, and UV-Vis spectroscopy and conductance measurements. The spectroscopic data support square planar environment around the CuII atom, while the SnIV atom acquires pentacoordinate geometry. The interaction of complex (5) with guanine, adenine, and calf thymus DNA was studied by spectrophotometric, electrochemical, and kinetic methods. The absorption spectra of complex (5) exhibit a remarkable “hyperchromic effect” in the presence of guanine and calf thymus DNA. Indicative of strong binding of the complex to calf thymus DNA preferentially binds through N7 position of guanine base, while the adenine shows binding to a lesser extent. The kinetic data were obtained from the rate constants, kobs, values under pseudo-first-order conditions. Cyclic voltammetry was employed to study the interaction of complex (5) with guanine, adenine, and calf thymus DNA. The CV of complex (5) in the absence and in the presence of guanine and calf thymus DNA altered drastically, with a positive shift in formal peak potential Epa and Epc values and a significant increase in peak current. The positive shift in formal potentials with increase in peak current favours strong interaction of complex (5) with calf thymus DNA. The net shift in E1/2 has been used to estimate the ratio of equilibrium constants for the binding of Cu(II) and Cu(I) complexes to calf thymus DNA.
PMCID: PMC1686294  PMID: 17497007
10.  Structure-Activity Relationships of Synthetic Coumarins as HIV-1 Inhibitors 
HIV/AIDS pandemics is a serious threat to health and development of mankind, and searching for effective anti-HIV agents remains actual. Considerable progress has been made in recent years in the field of drug development against HIV. A lot of structurally different coumarins were found to display potent anti-HIV activity. The current review demonstrates the variety of synthetic coumarins having unique mechanism of action referring to the different stages of HIV replication. Recent studies based on the account of various synthetic coumarins seem to indicate that some of them serve as potent non-nucleoside RT-inhibitors, another as inhibitors of HIV-integrase or HIV-protease. The merits of selecting potential anti-HIV agents to be used in rational combination drugs design and structure-activity relationships are discussed.The scientific community is looking actively for new drugs and combinations for treatment of HIV infection effective for first-line treatment, as well as against resistant mutants. The investigation on chemical anti-HIV agents gives hope and optimism about it. This review article describes recent progress in the discovery, structure modification, and structure-activity relationship studies of potent anti-HIV coumarin derivatives.
PMCID: PMC1686293  PMID: 17497014
11.  Synthesis, Characterization, and Biotoxicity of N N⌢ Donor Sulphonamide Imine Silicon(IV) Complexes 
The organosilicon derivatives of 2-[1-(2-furayl)ethyledene]sulphathiazole with organosilicon chlorides have been synthesised and characterized on the basis of analytical, conductance, and spectroscopic techniques. Probable trigonal bipyramidal and octahedral structures for the resulting derivatives have been proposed on the basis of electronic, IR, 1H, 13C NMR, and 29Si NMR spectral studies. In the search for better fungicides, bactericides, nematicides, and insecticides studies were conducted to assess the growth-inhibiting potential of the synthesized complexes against various pathogenic fungal, bacterial strains, root-knot nematode Meloidogyne incognita, and insect Trogoderma granarium. These studies demonstrate that the concentrations reached levels which are sufficient to inhibit and kill the pathogens, nematode, and insect.
PMCID: PMC1686292  PMID: 17496998
12.  Lanthanide(III) and Yttrium(III) Complexes of Benzimidazole-2-Acetic Acid: Synthesis, Characterisation and Effect of La(III) Complex on Germination of Wheat 
The synthesis and characterisation of lanthanide(III) and yttrium(III) nitrate complexes of benzimidazole-2-acetic acid (HBIA) are reported. The complexes have been characterised by elemental analysis, molar conductance, magnetic studies, IR, 1H NMR, UV-visible, EPR, and TG/DTA studies. They have the stoichiometry [Ln3(BIA)2(NO3)7(H2O)4] · 3H2O where Ln=La(III), Pr(III), Nd(II), Sm(III), Eu(III), Gd(III), Tb(III), Dy(III), and Y(III). The effect of La(III) complex on germination, coleoptile, and root length of two local varieties of wheat DWR-195 and GW-349 for different treatment periods has been investigated. The complex was found to exhibit enhanced activity, compared to HBIA or metal salt alone at lower treatment periods.
PMCID: PMC1686291  PMID: 17497017

Results 1-12 (12)