Antioxidative and antitumour properties of metal(II) solid complexes with 8-acetyl-4-methyl umbelliferone

Six transition metal(II) complexes with 8-acetyl-4-methyl umbelliferone (AM UH), ML2 (L = AMU(-); M = Mn, Co, Ni, Cu, Zn and Cd), have been synthesized and characterized by elemental analysis, electrical conductance, i.r., H-1 -n.m.r. and u.v. spectroscopic techniques. The e.s.r. spectra show that CuL 2 is anisotropic, with g(perpendicular to) approximate to 2.05 and g(|) |ap proximate to 2.26. The MnL2 species is characterized by a very broad g appr oximate to 2 centered resonance without manganese hyperfine structure. The antioxidative and other biological activities of selected complexes were al so investigated, indicating that both the ligand and complexes exhibit a sc avenging effect on the superoxide radical (O-2(-.)) and a suppressing effec t on the hydroxyl radical ((OH)-O-.). The suppressing effect on (OH)-O-. is greater than the scavenging effect on O-2(-.). The Cu and Mn complexes exh ibit very significant suppression ratios for both radicals. However, the in hibitory effect on lipid peroxides results show that, in the initial stage, the Cu and Mn complexes exhibit obvious inhibitory effects on lipid peroxi des, but after one hour, they begin to accelerate the lipid peroxides. Lowe r catalytic activity and instability when the complexes react with active o xygen may be responsible for this dual nature. The ligand and four transiti on metal(II) complexes selectively, obviously, inhibit the growth of HCT-8 and HL-60 tumour cell lines. They also exhibit a minor influence on the pro liferation of B cells in higher concentration (10(-5) m), but only a weak e ffect on the proliferation of T cells of the BALB/C (nude rate) spleen cell s.