Copper(i) complexes with phosphine derived from sparfloxacin. Part III: multifaceted cell death and preliminary study of liposomal formulation of selected copper(i) complexes.

The cytotoxic effect of iodide or thiocyanate copper(i) complexes (1-PSf, 2-PSf, 3-PSf, 4-PSf) with phosphine derived from sparfloxacin (HSf) and 2,9-dimethyl-1,10-phenanthroline (dmp) or 2,2'-biquinoline (bq) as diimine auxiliary ligands was proved in vitro on somatic (MRC-5) and neoplastic (MCF7) human cell lines. Differences in mode of action were investigated in-depth for the selected dmp and bq complexes (1-PSf, 3-PSf, respectively) by elucidation of the following: (i) the efficiency to produce reactive oxygen species (ROS) in biological systems (cyclic voltammetry); (ii) their impact on mitochondrial membrane potential; (iii) potency for the activation of caspases 3 and 9; (iv) influence on the degree of DNA degradation (comet assay). It was concluded that the apoptosis of cancer cells is directly connected to the caspase-dependent mitochondrial pathway and supported by ROS production along with irreversible DNA fragmentation. Finally, it was demonstrated that the selected copper(i) complex encapsulated inside liposomes (1-PSf-L) exhibited enhanced accumulation inside cancer cells. This resulted in its higher cytotoxicity against cancer cells with therapeutic index of ca. 60. Increased selective accumulation in active neoplasm with simultaneous enhanced bioavailability and reduced systemic toxicity of liposomal formulation of copper(i) complexes can result in the development of new copper-based therapeutics and their successful implementation in anticancer chemotherapy.

The changes of antioxidant defense system caused by quercetin administration do not lead to DNA damage and apoptosis in the spleen and bone marrow cells of rats.

Quercetin may have the opposite effect, namely anti- as well as pro-oxidant. The aim of this study was to assess the results of quercetin anti- and/or pro-oxidant activity in the bone marrow and spleen cells of rats. The experimental rats were treated daily, with quercetin in a dose of 8 or 80mg/kg b.w. by gavage for 40 days. The intracellular redox state in cells were assessed by measuring the ferric ion reducing antioxidant power (FRAP) level and malonodialdehyde concentration. HO-1 mRNA expression was examined with real-time PCR. The extent of DNA damage was determined by the alkaline-labile comet assay. A potential pro-apoptotic quercetin action was determined using the FITC-Annexin V kit. The quercetin and isorhamnetin concentrations in serum were analyzed by HPLC-ECD. MDA concentration and FRAP values, were significantly decreased in the spleen and bone marrow cells of rats treated with quercetin, in a dose of 80mg/kg b.w. in comparison with the control rats; no significant changes were observed after quercetin was administered in a dose ten times as low. Treatment with quercetin dose-dependently upregulated the expression of HO-1 mRNA in the bone marrow cells. Quercetin administration to the rats did not induce either DNA damage or apoptosis in the examined cells. The results of our study prove that changes in the antioxidant state, caused by quercetin, do not lead to DNA damage or exert any pro-apoptotic activity in vivo.

The protective ability of the Mediterranean plant extracts against the oxidative DNA damage. The role of the radical oxygen species and the polyphenol content.

The polyphenol plant extracts content seems to be responsible for the scavenging activity of the reactive oxygen species (ROS), resulting in protection against DNA damage induced by the oxidative stress. This assumption was verified analyzing the effect of six Mediterranean plant extracts (Crepis vesicaria L, Origanum heracleoticum, Scandix australis L, Amaranthus sp., Scolymus hispanicus L, Thymus piperella L) on the oxidative DNA damage induced in lymphocytes by H(2)O(2) in relation to the polyphenolic content and the lymphocyte scavenging ability of ROS. The comet assay was used to evaluate oxidative DNA damage and the polyphenol content was analyzed by the Folin-Ciocalteu method. The fluorescence resulting from oxidation of ROS-sensitive dye, dihydrorofluorescein (DHF), was utilized as indicator of the ROS level. Pretreatment with all plant extracts produced the dose-dependent increase in the DNA protection up to the 0.2 microg/ml polyphenol content and the decrease above that dose. Only the Thymus piperella, similarly to quercetin, showed a strong positive correlation between the DNA protection and the polyphenol content, but negative correlation with ROS formation. In conclusion, the DNA protective ability of plant extracts seems to be related to the low polyphenol concentration and only to certain extent depends on the polyphenol ROS scavenging activity.

Modulatory effect of quercetin on DNA damage, induced by etoposide in bone marrow cells and on changes in the activity of antioxidant enzymes in rats.

The aim of the studies was to evaluate the influence of quercetin on etoposide-induced DNA damage in rat bone marrow cells and on changes in the activities of superoxide dismutase (SOD), catalase and antioxidant power in lung tissue (AOP). Quercetin was administrated by gavage at a dose of 135 mg/kg b.w. for three consecutive days, and one hour after the last dose, etoposide was intraperitoneally injected, at dose of 80 mg/kg b.w. Bone marrow cells were harvested from the femurs 24 hours later and DNA damage was evaluated by the comet assay, under alkaline condition. The study provided evidence that quercetin, administered to rats, provides major protection against etoposide-induced DNA damage in bone marrow cells and does not influence either the SOD activity, lowered by etoposide, or AOP, enhanced by etoposide.