Özlem Yildirim

Effects of supplementation with a combination of cobalt and ascorbic acid on antioxidant enzymes and lipid peroxidation levels in streptozocin-diabetic rat liver.

The effect of cobalt(II) chloride (CoCl2) and CoCl2 with ascorbic acid (AA) on components of the antioxidant defense system and lipid oxidative damage were studied in controls and streptozotocin-induced diabetic rat livers. Three days after injection, rats received either 0.5 mM CoCl2 or 0.5 mM CoCl2 with a combination of 1 g/L AA in drinking water up to 6 wk. The elevated blood glucose levels in diabetic rats were about 12% restored by oral administration of CoCl2 (0.05 mM) and were significant reduced (46%) following AA addition (1 g/L) to CoCl2. Cobalt therapy effectively decreased the increased activities of catalase (CAT), superoxide dismutase (SOD), and thiobarbituric acid reactant substances (TBARS) but could not restore the increased glutathione peroxidase (GSH-Px) in the liver of diabetic rats. Our findings suggest that cobalt therapy may prove effective in improving the impaired antioxidant status during the early state of diabetes, and ascorbic acid supplementation at this dose potentiates the effectiveness of cobalt action.

Batch and Continuous Hydrolysis of Lactose Using P-Galactosidase Immobilized on Gelatin-Cmc

Abstract β-Galactosidase enzyme (E.C. 3.2.1.23) was immobilized onto a gelatin-carboxymethylcellulose carrier system by using cross-linker chromium acetate. A relative activity increase of 33% was achieved by adding carboxymethylcellulose to gelatin. The effect of operation temperature and pH on relative activity and reusability of the immobilized enzyme was investigated. A fluidized-bed reactor with a down flow mechanism was used for continuous process hydrolysis, and a constant glucose production rate was obtained.

Glutathione S-Transferase M1 and T1 Gene Polymorphism in Patients with Lung Cancer Among Turkish Population

ABSTRACT Several polymorphic genes including those encoding for glutathione S-transferases (GSTs) have been reported to be associated with development of specific cancers. Individual variations in the expression of these enzymes have been extensively studied. In this study, the implication of two GST genes (GSTM1 and GSTT1) in the development of different types of lung cancer was investigated in Turkish patients (N=44). Our results show a 72.3% allele frequency for null GSTM1 gene among lung cancer patients and for healthy individuals (N=100) it was found to be 34%. The GSTM1 null genotype is slightly over represented in lung cancer patients (OR=0.73; CI=0.33–1.59) but did not reach a statistical importance. The frequency of deleted GSTT1 allele was 19% in normal controls that is consistent with the previous results for Caucasians. GSTT1 null genotype frequency among lung cancer patients (20.5%) was very Close to the control group (OR=0.91, CI=0.38–2.21). In all lung cancer cases 13.6 % of the patients showed homozygous deletion of both GSTM1 and GSTT1 gene and in control group 10% of the individuals had both deletion (p=0.08) suggesting that null GSTM1 and GSTT1 genotypes do not interact to potentiate the risk of lung cancers in Turkish patients.

Stability and storage conditions of NADH-cytochrome b5 reductase cross-linked into gelatin by chromium (III) acetate

NADH-cytochrome b5 reductase was isolated and partially purified from rabbit liver microsomes. It was immobilized into gelatin by chemical cross-linking. Chromium (III) acetate was used as cross-linker. The effects of pH and temperature on the immobilized cytochrome b5 reductase were investigated. The reusability and storage stability of immobilized enzyme were also tested. Immobilized NADH-cytochrome b5 reductase activities were found to be stable for at least 72 d and 24 uses. The storage stability of NADH-cytochrome b5 reductase was improved with immobilization at 25 degrees C.

The potential medicinal value of plants from Asteraceae family with antioxidant defense enzymes as biological targets.

Abstract Context: Plants and most of the plant-derived compounds have long been known for their potential pharmaceutical effects. They are well known to play an important role in the treatment of several diseases from diabetes to various types of cancers. Today most of the clinically effective pharmaceuticals are developed from plant-derived ancestors in the history of medicine. Objective: The aim of this study was to evaluate the free radical scavenging activity and total phenolic and flavonoid contents of methanol, ethanol, and acetone extracts from flowers and leaves of Onopordum acanthium L., Carduus acanthoides L., Cirsium arvense (L.) Scop., and Centaurea solstitialis L., all from the Asteraceae family, for investigating their potential medicinal values of biological targets that are participating in the antioxidant defense system such as catalase (CAT), glutathione S-transferase (GST), and glutathione peroxidase (GPx). Materials and methods: In this study, free radical scavenging activity and total phenolic and flavonoid contents of the plant samples were assayed by DPPH, Folin–Ciocalteu, and aluminum chloride colorimetric methods. Also, the effects of extracts on CAT, GST, and GPx enzyme activities were investigated. Results and discussion: The highest phenolic and flavonoid contents were detected in the acetone extract of C. acanthoides flowers, with 90.305 mg GAE/L and 185.43 mg Q/L values, respectively. The highest DPPH radical scavenging was observed with the methanol leaf extracts of C. arvense with an IC50 value of 366 ng/mL. The maximum GPx and GST enzyme inhibition activities were observed with acetone extracts from the flower of C. solstitialis with IC50 values of 79 and 232 ng/mL, respectively.

Active Oxygen Scavenging Enzyme Activities and Glutathione, Ascorbic Acid and Lipid Peroxidation Levels in Developing Vitis Vinifera L. Leaves and Berries

ABSTRACT Variations and activities of active oxygen radical scavenging enzymes and the level of glutathione (GSH), lipid peroxide and ascorbic acid levels were measured during the developmental cycle and their relationship were examined in two grape cultivars, Kalecik Karasi and Sultani Çekirdeksiz (Vitis vinifera L.). The catalase activity was very low and did not change during growth, the activity of superoxide dismutase significantly decreased through the maturity. There was no significant difference between two cultivars for glutathione peroxidase activity at maturity. The maximum glutathione level was observed in berries of two Vitis vinifera L. cultivars. Ascorbic acid levels were significantly increased in young and old leaves. Changes in the activities of antioxidant enzymes and levels of glutathione, ascorbic acid and thiobarbituric acid reactive substances were related to the development of berries and leaves.

Screening Effects of Methanol Extracts of The Diplotaxis tenuifolia and Reseda lutea on The Enzymatic Antioxidant Defense Systems and Aldose Reductase Activity

Objectives: The aim of the study was to investigate the effects of methanol extracts from the flowers and leaves of Diplotaxis tenuifolia and Reseda lutea on the activity of AR, CAT, GST, and GPx. Materials and Methods: Total phenolic and flavonoid contents of the plant samples were evaluated using Folin-Ciocalteu reagent and aluminum chloride colorimetric methods. Also, the effects of extracts on CAT, GST, GPx, and AR enzyme activities were investigated using kinetic assays. Results: The highest phenolic and flavonoid contents were detected in the methanol extract of D. tenuifolia leaves with 144.49±0.29 mg gallic acid equivalent/L and 250.485±0.002 quercetin equivalent/L, respectively. The best activity profile for GST and GPx were observed in the extract of leaves belonging to D. tenuifolia with IC50 values of 121±0.05 and 140±0.001 ng/mL, respectively. According to the results, methanol extracts from leaves of R. lutea and D. tenuifolia showed no significant activity potential on AR. Moreover, none of the studied extracts demonstrated any reasonable CAT activation potential. Conclusion: The results indicated that leaves of D. tenuifolia had good effect on the antioxidant enzymatic defense system, which it makes it a good constituent of the daily diet.

Changes in Nitric Oxide Level of Different Tissues in Diabetic Rats

ABSTRACT The relationship between tissues and nitric oxide (NO) levels were studied in streptozotocin diabetic rats. Animals were sacrified two, four and eight weeks after saline or streptozotocin (45 mg/kg, i.p.) injection. Nitric oxide level in the rat tissues (liver, lung, kidney, spleen and testis) was estimated by determination of nitrite and nitrate using Griess reaction. Significant variation of nitric oxide levels according to tissues was demonstrated statistically. NO levels in the liver and kidney were significantly increased at all times studied, conversely decreased in lung, spleen and testis (p < 0.05) at different period of diabetes. In the lung, there was no change in the nitric oxide level returned to the control levels at 4 and 8 weeks.

Antioxidant Defense System in Cobalt Treated Diabetic Rat Lung

ABSTRACT To study the effect of cobalt intake on catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and the levels of lipid peroxidation by measuring thiobarbituric acid reactive substance (TBARS), streptozotocin (STZ)-induced diabetic rats were treated with cobalt chloride (CoC12)(0.5 mM in the drinking water) for up to 44 days. Diabetes was associated with a significant increase in the activity of CAT, SOD, GSH-Px and TBARS in lung. Cobalt therapy effectively normalized the increased activities of CAT, SOD and TBARS levels but could not restore GSH-Px in the lung. The ensemble of results suggests that, the cobalt dose which was used in this study can be considered as the regulation of oxidative and antioxidative systems.