Ruhi Uyar

Syntheses, characterization, antimicrobial and cytotoxic activities of pyridine-2,5-dicarboxylate complexes with 1,10-phenanthroline.

In this study, four mononuclear M(II)-pyridine-2,5-dicarboxylate (M = Co(II), Ni(II), Cu(II) and Zn(II) complexes with pyridine-2,5-dicarboxylic acid or isocinchomeronic acid, 1,10-phenanthroline (phen), [Co(Hpydc)(2)(phen)]·H(2)O (1), [Ni(pydc)(phen)(2)]·6.5H(2)O (2) [Cu(pydc)(phen)(H(2)O)(2)] (3) and [Zn(pydc)(phen)(H(2)O)(2)]·H(2)O (4) have been synthesized. Elemental, thermal and mass analyses, molar conductance, magnetic susceptibilities, IR and UV/vis spectroscopic studies have been performed to characterize the complexes. Subsequently, these ligands and complexes were tested for antimicrobial activity by disc diffusion method on Gram positive, negative bacteria and yeast. In addition, cytotoxic activity tests were performed on rat glioma (C6) cells by MTT viability assay for 24 and 48 h. Antimicrobial activity results demonstrated that when compared to the standard antibiotics, phen displayed the most effective antimicrobial effect. The effect of synthesized complexes was close to phen or less. Cytotoxic activity results showed that IC(50) value of phen was determined as 31 μM for 48 h. (1) and (2) compared to the alone ligand had less toxic activity. IC(50) values of (3) for 24 and 48 h treatments were 2.5 and 0.6 μM, respectively. IC(50) value of (4) for 48 h was 15 μM. In conclusion, phen, (3) and (4) may be useful as antibacterial and antiproliferative agents in the future.

Quercetin both partially attenuates hydrogen peroxide-induced toxicity and decreases viability of rat glial cells.

Quercetin is one of the most ubiquitous flavonoids in foods of plant origin. Although quercetin is generally considered to provide protection against oxidative injury, recent studies have shown to be cytotoxic to many cell types. We intended here to determine whether quercetin protects against H2O2-induced toxicity and/or affects viability of rat mixed glial cells. The cells were obtained from 1-3 day olds rat brains and incubated in a humidified atmosphere of 5% CO2, at 37 °C in flasks. In the quercetin groups, different quercetin concentrations (1, 10, 50, 75 or 100 μM) were applied alone for 24 h. For H2O2 cytotoxicity group, the glial cells were treated for 3 h with 100 μM H2O2 which induced 75% cell death. In another group, the cells were treated with 100 μM H2O2 plus respective quercetin concentrations simultaneously for 3 h, the medium was removed and refed for 24 h. MTT test was then applied and statistical significance was ascertained by one way analysis of variance, followed by Tukeys multiple comparison test. Quercetin starting from 50 μM decreased the glia survival significantly. In H2O2 plus quercetin co-treated groups, both 75 and 100 μM quercetin attenuated toxic effect of H2O2 by 15%. In conclusion, quercetin both partially protects H2O2-induced gliotoxicity and decreases rat glial cell viability in primary culture.

Carvacrol attenuates cyclophosphamide-induced oxidative stress in rat kidney

Cyclophosphamide (CP) is an antineoplastic drug that induces kidney damage via producing oxidative stress. Carvacrol (CAR) has antioxidative effect and we postulated that it can be protective against CP-induced nephrotoxicity. Six groups (n = 7) of rats (control, 100 mg/kg CP, CP+5 mg/kg CAR, CP+10 mg/kg CAR, 5 mg/kg CAR, and 10 mg/kg CAR) were injected intraperitoneally. Serum malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT), creatinine (CRE), total antioxidant capacity (TAC), and total oxidant state (TOS) were measured, and oxidative stress indexes (OSI) were calculated. Kidneys were also analyzed histologically. In CP-alone group MDA, CRE, TOS, and OSI levels increased whereas GSH, SOD, CAT, and TAC levels decreased compared with control group. In CP plus CAR groups, MDA, TOS, and OSI levels decreased whereas GSH, SOD, CAT, and TAC levels increased compared with CP-alone group. However, CRE levels were similar in CP-alone and CP+5 CAR group whereas decreased in CP+10 CAR group. CP+10 CAR group was significantly different in all parameters (except TAC) from CP+5 CAR group. Kidney microscopy was showed lower tissue damage in CP plus CAR groups. In conclusion, 10 mg/kg CAR is more effective than 5 mg/kg CAR in prevention of CP-induced oxidative damage on kidney.

Licofelone abolishes survival of carcinogenic fibroblasts by inducing apoptosis.

Abstract Dual inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX) pathways of arachidonic acid metabolism prevent cancer development and induce apoptosis. One of the most promising compounds that blocks both of these pathways is licofelone. We questioned whether licofelone affects the survival and/or promotes apoptosis of H-ras transformed rat embryonic fibroblast (5RP7) cells in vitro. Using 5-fluorouracil (5-FU) and colchicine as positive controls, we determined cell viability with 3-3-(4,5-D-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, thyazolyl blue (MTT), apoptosis with flow cytometry and activity of caspase enzyme with real-time reverse transcription polymerase chain reaction (PCR). Compared to the control, all used six doses (10, 50, 100, 150, 250 and 250 µM) of 5-FU, colchicine and licofelone, which were cytotoxic and reduced the number of H-Ras transformed 5RP7 cells by as much as 78, 72 and 92%, respectively. In addition, we found that 150, 200 and 250 µM of licofelone induced apoptosis and necrosis of H-Ras transformed 5RP7 cells in a dose- and time-dependent manner. Each three tested drugs at 250 µM also increased the level of caspase-3 enzyme up to 5-fold. Although colchicine was effective in inducing early apoptosis, licofelone had much more capacity to induce the total of early plus late apoptosis by approximately 96% in cells after 48 hours. The present study reveals the possibility that licofelone posseses strong dose- and time-dependent anticancer and apoptotic properties on carcinogenic fibroblasts.

Cytotoxic and apoptotic functions of licofelone on rat glioma cells

Gliomas are the largest group of central nervous system tumors and despite of clinical treatments death rate is very high. Inhibition of both cyclooxygenase and lipoxygenase pathways that take role in arachidonic acid metabolism prevents cancer development and induces apoptosis. One of the most promising compounds that blocks both of these pathways is licofelone. Using colchicine and 5-fluorouracil as positive controls, we questioned whether licofelone affects the survival of rat glioma cell line (C6) and induces apoptosis in vitro. After growing the cells in culture, we determined viability with MT, apoptosis with flow cytometry and activity of caspase enzymes with real time PCR. All used doses of colchicine and 5-fluorouracil were cytotoxic and reduced the number of surviving C6 cells as much as 44% and 60%, respectively. Comparing to the control, treatments with 10, 50 and 100 μM licofelone for 24 or 48 h did not influence C6 survival, however, 150, 200 and 250 μM licofelone reduced the number of living cells by 58, 88 and 93%, respectively, and induced apoptosis of C6 cells in a dose and time dependent manner. Licofelone did not change the level of caspase-9, but increased the level of caspase-3. Comparing with 5-fluorouracil and colchicine, the present study reveals for the first time the possibility that licofelone possesses a strong dose and time dependent antiproliferative and proapoptotic properties on glioma cells.

Prostaglandin-lndependent Decrease of Sheep Ureter Contractility Induced by Bradykinin

The mechanisms that mediate the actions of bradykinin on ureteral motility are poorly defined and mediation via prostaglandins has not been examined. Therefore, the effects of bradykinin on contractility and the possible mediator role of prostaglandins have been investigated in sheep ureter. At the concentrations of 10(-8), 10(-7) and 10(-6) M, bradykinin elicited marked reductions in contractile force. When ureteral strips were treated separately with 10(-6) M indomethacin, 2 x 10(-6) M sodium salicylate and 10(-5) M aspirin, each drug produced a significant decrease in contractile force. In strips in which prostaglandin synthesis was inhibited by the above concentrations of indomethacin, sodium salicylate and aspirin, 10(-7) M bradykinin significantly decreased the contractility. From these data, we concluded that in ureter bradykinin decreases contractility via a mechanism not involving prostaglandin generation.

The actions of leptin on survival and hydrogen peroxide toxicity in primary mixed glial cells of rat

Studies indicate that leptin is involved in not only energy expenditure and food intake, but also in protection against apoptosis, in inflammation and in stimulation of proliferation in many cell types. However, leptin treatment increases the oxidative stress in many cell culture studies. This contradiction evoked a question of whether leptin acts as an oxidant or antioxidant on glial cells. We investigated the effect of leptin on glial cell survival and hydrogen peroxide (H2O2)-induced toxicity in vitro. The survival rate of the cells was determined by using 3-(4,5-D-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, thyazolyl blue (MTT) method. The cells obtained from the whole brain of 1–3 day-old rat were treated with 1, 10, 100 and 1000 ng/mL leptin for 24 or 72 h. Either the pretreatment of leptin alone for 5 h or leptin combined simultaneously with H2O2 or well known antioxidant glutathione (GSH) were applied to the cells. Malondialdehyde (MDA) levels were measured in cell lysates to which leptin was added for 24 h. The 100 and 1000 ng/mL leptin treatment for 72 h increased the glial viability by 19% and 36%, respectively. The dose of H2O2 that killed 75% of the cells was determined as 100 µM. GSH at different doses was applied as a positive control to the cells and the dose of 500 µM completely eliminated toxic effect of 100 µM H2O2. Either the pretreatment of leptin alone for 5 h or leptin combined simultaneously with H2O2 could not eliminate H2O2-caused toxicity. Furthermore, respective leptin doses did not change the glia MDA level. We suggest that leptin can increase glia survival dose dependently, but can not eliminate H2O2-induced oxidation in primary mixed glial cell culture.

Erratum: Protective effect of zinc on cyclophosphamide-induced hematoxicity and urotoxicity: (Biol Trace Elem Res (2008) 126 (186-193) DOI 10.1007/s12011-008-8189-5)

The original version of this article unfortunately contained a mistake. The Materials and Methods section should include last paragraph. Section “Materials and Methods”, inclusion of the last paragraph should read: Only the groups which had CY treatment alone were killed 3 days after the CY injection. For the groups having Cy+ZnCl2 , ZnCl2 administration was started three days earlier than the CY administration and continued till the end of the experiment (6 days). On the fourth day the animals were weighed again, relative doses of CY were estimated and CY+ZnCl2 was administered together. On the seventh day blood samples were collected, bone marrow and the urinary bladders of the animals were resected under anesthesia. Also, the first three affiliations were incorrect. The correct information is given below. Biol Trace Elem Res (2009) 127:284 DOI 10.1007/s12011-008-8292-7