Synthesis and Characterization of Glucose-Bis(pyrazole)-Cu(II)/Ni(II) Complexes and Their in Vitro DNA Binding Studies

Abstract

In the forefront is the recent area of glycobiology a "sweet and safe" approach for the development of new drugs in medicinal inorganic chemistry.1) The use of glycosyl substituents for enhanced tissue target, improved solubility and reduced toxicity has attracted many researchers to explore the possibility of carbohydrate-based drug strategies. [2][3][4][5] Chen et al. have synthesized a novel carbohydrate linked to cisplatin analogue, cis-dichloro [(2-b-D-glucopyranosidyl)propane-1,3-diamine]platinum and examined selective cytotoxicity towards cancer cells.6) This complex exhibits specific in vitro antitumour activity against human ovarian cancer cell A2780S and human melanoma cancer cell MeWo. Some of the cancer cell antigens are carbohydrates and several trials are being carried out to develop carbohydrate derived cancer vaccines.7) Globo H is a prominent epitope on cancer cells; therefore a potential vaccine was prepared consisting of the synthetic hexasaccharide chain of Globo H linked to KLH. 8)Recently, Nakase et al. have demonstrated artemisinin tagged to transferrin via carbohydrate chain exhibits high potency and specificity against cancer cells. 9) Carbohydrate linked to biologically relevant molecules like pyrazole and imidazole act as an attractive scaffold for transition metal ions. [10][11][12] The interaction of transition metal-saccharide complexes with DNA is significantly important (DNA is one of the main molecular targets in the action of anticancer drugs), as many naturally occurring antitumour agents are capable of modifying nucleic acids only in presence of metal ions and oxygen. [13][14][15][16] Of these antitumour agents, a vast majority usually contains sugar derivatives as their back bone. Thus, there has been profound interest in the design, study of DNA binding and cleavage properties of glucose-derived transition metal complexes and development of these complexes as metallo-drugs. 17,18) Since there are many alterations in the genes that code for the protein in tumor, the focus of such studies is also on proteins which drive and control cell cycle progression. 19,20) Herein, we describe the synthesis, characterization of Dglucose-bis pyrazolyl metal complexes of Cu(II) 1 and Ni(II) 2 and their binding properties with CT DNA. Furthermore, DNA cleavage of pBR322 DNA by complex 1 was carried out by employing agarose gel electrophoresis. The "binding study" of complex 1 towards human serum albumin (HSA), L-tryptophan and their mixtures with DNA was studied to recognize the most favoured biomolecule, for which it shows highest binding affinity. ExperimentalMaterials and Methods D-Glucose, CuCl 2 · 2H 2 O, NiCl 2 · 6H 2 O (Qualigens), pyrazole (Fluka). Tris (TrisϭTris(hydroxymethyl)aminomethane) base (Merck), 6ϫ loading dye (Fermental Life Science) and super coiled plasmid DNA pBR322 (Genei) were utilized as received. Disodium salt of calf thymus DNA, human serum albumin and L-tryptophan were purchased from Sigma Chemical Company and stored at 4°C. All reagent grade compounds were used w...

Iron(III) phthalocyanine chloride-catalyzed oxidation–aromatization of α,β-unsaturated ketones with hydrazine hydrate: Synthesis of 3,5-disubstituted 1H-pyrazoles

“…Pyrazoles are also used as building blocks in synthetic organic chemistry, versatile, pluripotent ligands in coordination chemistry [9][10][11][12][13], and in transition-metal cross-coupling and polymerization reactions [14][15][16][17]. These heterocycles have also attracted much interest because of their technological impacts, e.g., as ultraviolet stabilizers, photoprotecting agents, and energetic materials [18][19][20][21][22].…”