No abstract

The antioxidant activity of Ge-132 (2-carboxyethylgermanium sesquioxide, [(O 0.5) 3 GeCH 2 CH 2 COOH] n), a widely used organic germanium dietary supplement, was assessed by cyclic voltammetry and through its interaction with a stable radical 2,2,-diphenyl-1picrylhydrazyl (DPPH) monitored by UV-Vis and EPR spectroscopy in water, CH 3 CN, DMF, MeOH, and their mixtures with water. The results obtained by these methods are coherent in that Ge-132 can manifest its antioxidant activity only in the absence of water because the latter hydrolyses its Ge-O-Ge fragment responsible for quenching free radicals. Thus, contrary to a common use of Ge-132 as a water-soluble agent, it can act as an antioxidant solely in a lipid environment, which is important for understanding the mechanism of its biological activity.

Growth kinetics of human breast tumor cell in the presence of doxorubicin was studied using the method of UV spectrophotometery. Parameters of ecotoxicological cell growth model were established. Cell number predicted by the model equation corresponded to the observed cell count within the experimental error. The therapeutic dose of doxorubicin hydrochloride was determined.

Complexes of tetra-and hexa-coordinated germanium Adr Cat 2 Ge (1, Adr Cat = adrenaline catecholate), Ald Cat 2 Ge (2, Ald Cat = 4-formylcatecholate), Ald Cat 3 Ge(Et 3 NH) 2 (3) were synthesized by the reaction of germanium dioxide with adrenaline and 3,4-dihydroxybenzaldehyde in aqueous solution. The structures of the complexes were confirmed by 1 H and 13 C NMR and IR spectroscopy, HRMS, and elemental analysis. Cyclic voltammetry in phosphate buffer solutions (pH = 6.86) has shown the oxidation potentials E p of these complexes to be shifted by ca. 330-360 mV to more positive potentials compared to the parent aromatic diols, which means that their electron-releasing properties were diminished by about 7.6-8.3 kcal mol -1 . A study of the kinetics of the reaction of these complexes with 2,2diphenyl-1-picrylhydrazyl (DPPH) free radical in the presence of [a] N.