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A new series of complexes of a ligand 4', 7, 8-trihydroxy-isoflavone with transition metal (zinc, copper, manganese, nickel, cobalt) and selenium have been synthesized and characterized with the aid of elemental analysis, IR, electron ionization mass spectrum (EI-MS) and (1)H NMR spectrometric techniques. The compounds were evaluated for their in vitro antibacterial activities and antitumor properties. The metal complexes were found to be more active than the free ligand. Investigation on the interaction between the complexes and calf-thymus DNA (CT DNA) showed that the absorbance of CT DNA increased and the maximum peak (λ(max)=260 nm) red-shifted, while the intensity of fluorescence spectra of Epstein-Bart DNA (EB-DNA) gradually weakened, which indicated that all of these metal complexes tightly combined with CT DNA., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Five new complexes were synthesized by the reaction of 4'-methoxy-5,7-dihydroxy-isoflavone ligand (a) with transition metal ions zinc (Zn(2+)) (complex b), manganese (Mn(2+)) (complex c), copper (Cu(2+)) (complex d), cobalt (Co(2+)) (complex e) and nickel (Ni(2+)) (complex f). The composition of the complexes has been characterized by elemental analysis, IR, mass spectrometry (MS) and (1)H NMR spectrometric techniques. Their antitumor properties were evaluated against five human cancer cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and flow cytometry. The results indicated that the complexes possess higher growth inhibitory effects than free isoflavone and corresponding metal ions. Complex c and f showed greater antitumor activity and selectivity than other described complexes, even more effective than the positive control cisplatin against the selected cell lines. In addition, DNA flow cytometric analysis demonstrated that complexes display a significant G(2)/M phase arrest, which then progressed to early apoptosis as detected by flow cytometry after double-staining with annexin V and propidium iodide (PI)., (Copyright 2009 Elsevier Inc. All rights reserved.)