Three novel complexes [Nd(L)(NO3)(H2O)2].NO(3).2H2O (HL1 = N-pyrimidine norcantharidin acylamide acid, C12H13N3O4; HL2 = N-pyridine norcantharidin acylamide acid, C13H14N2O4; HL3 = N-phenyl norcantharidin acylamide acid, C14H15NO4) were synthesized. HL1, HL2 and HL3 are the ligand of complex(1), complex(2) and complex(3), respectively. Their structures were characterized by elemental analysis, conductivity measurement, infrared spectra and thermogravimetric analysis. The DNA-binding properties of the complexes have been investigated by fluorescence spectroscopy and viscosity measurements. The results suggest that the complexes can bind to DNA by partial intercalation. The liner Stern-Volmer quenching constant Ksq values are 3.3(+/-0.21)(1), 1.7(+/-0.19)(2) and 0.9(+/-0.04)(3), respectively. Complex (1) and (2) have been found to cleave pBR322 plasmid DNA at physiological pH and temperature. The test of antiproliferation activity indicates that complex(1) has strong antiproliferative ability against the SMMC7721 (IC50 = 131.7 +/- 23.4 micromol x L(-1)) and A549 (IC50 = 128.4 +/- 19.9 micromol x L(-1)) cell lines. The inhibition rates of complex(2) (IC50 = 86.3 +/- 11.3 micromol x L(-1)) are much higher than that of NCTD (IC50 = 115.5 +/- 9.5 micromol x L(-1)) and HL2 (111.0 +/- 5.7 micromol x L(-1)) against SMMC7721 cell lines.

H NMR and thermogravimetric analyses (TGA). The Schiff base ligand behaves as a tetradentate, coordinating through azomethine nitrogen, phenolic oxygen and two carboxylic oxygen atoms. The interaction of these complexes with calf thymus DNA (CT-DNA) was also investigated by spectrometric titration and viscometric measurements. The faint hypochromism of the complexes in the absorption spectra, the remarkable reduction of fluorescence intensity of ethidium bromide (EB) bound DNA, together with a small decrease in the viscosity of the DNA suggest that a partial intercalation may be the preferred binding mode between these two complexes and DNA. The antibacterial activity testing revealed that the complexes and their precursor Schiff base show a weak to moderate activity against Bacillus subtilis, Staphylococcus aureus and Escherichia coli.© Versita Warsaw and Springer-Verlag Berlin Heidelberg.

, respectively. Two compounds containing heterocycle of HL 1 and HL 2 have been found to cleave pBR322 plasmid DNA at physiological pH and temperature. The test of antiproliferation activity showed that the compounds had moderate to strong antiproliferative ability against the tested cell lines except of HL 3 against the SMMC7721 cell line. The results indicated that the heterocycle attached to the norcantharidin was favorable to antiproliferative activity. This result was consistent with the DNA binding experiment. Warsaw and Springer-Verlag Berlin Heidelberg. © Versita

No abstract

Source of materialNorcantharidin (0.5 mmol) and 2-aminopyridine (0.5 mmol) were dissolved separately in mixed solvents of acetonitrile and water (5:1 each, v/v). The first solution was added to the second solution. The mixture was stirred for 3 h, filtered and a white precipitate was obtained. The precipitate was dissolved in DMF and filtered to remove excessive solid. Colorless crystals suitable for X-ray structure determination were obtained from the filtrate by slow evaporation at room temperature. Experimental detailsThe H atoms were positioned geometrically and refined using the riding model (for atoms bound to C atoms), or their positions were refined using bond length restraints (for atoms bound to N or O at- , was prepared by synthesis of norcantharidin and 2-aminopyridine. By hydrolysis reaction, norcantharidin rearranges its carboxylic H atom and the cation is protonated at atom N2. As a result, cations and anions are held by electrostatic effect to form ionic compound. In addition, the crystal structure is stabilized by NH···O and OH···O hydrogen bonds between adjacent groups. The bond lengths and angles are in normal ranges.