Browsing by Author "Colak, Suat"

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The Ameliorative Effect of Cetraria Islandica Against Diabetes-Induced Genetic and Oxidative Damage in Human Blood
(Taylor & Francis Ltd, 2013) Colak, Suat; Geyikoglu, Fatime; Turkez, Hasan; Bakir, Tulay Ozhan; Aslan, Ali
Context: The aqueous extracts of Cetraria islandica (L.) Ach. (Parmeliaceae) is traditionally used in many countries against a number of conditions, including inflammatory conditions. Objective: The present study aimed to assess, for the first time, the effectiveness of C. islandica in cultured primary blood cells of Type 1 diabetes subjects. Materials and methods: Diabetic and control blood samples were treated with or without aqueous lichen extract (5 and 10 mu g mL(-1)) for 48 h. The activity of antioxidant enzymes in erythrocytes and also malondialdehyde levels in plasma were determined to evaluate the oxidative status. DNA damages were analyzed by SCE, MN and comet assays in cultured human lymphocytes. Additionally, proliferation index (PI) was evaluated in peripheral blood lymphocytes. Results: There were significant increases in observed total DNA damage (comet assay) (240.2%) and SCE (168.8%), but not in MN frequencies of cultures with diabetes as compared (p>0.05) to controls. Whereas, the significant reductions of total DNA damage (69.2 and 65.3%) and SCE frequencies (17.7 and 12.3%) were determined when the 5 and 10 mg mL(-1) lichen extract was added to the cell culture medium, respectively. However, lichen extract did not completely inhibit the induction of SCEs in lymphocytes of patients with diabetes. C. islandica extract was also useful on PI rates. Discussion: In conclusion, the antioxidant role of C. islandica in alleviating diabetes-induced genomic instability and for increasing cell viability was firstly indicated in the present study.
The Biochemical and Histological Effects of Lichens in Normal and Diabetic Rats
(Sage Publications Inc, 2016) Deniz, Gulsah Yildiz; Geyikoglu, Fatime; Turkez, Hasan; Bakir, Tulay Ozhan; Colak, Suat; Aslan, Ali
Oxidative stress plays an important role in causing diabetes; however, no studies have thoroughly reported on the toxic and beneficial effects of lichen extracts in patients with diabetes mellitus (DM). This study covers a previously unrecognized effect of two well-known lichen species Cetraria islandica and Pseudevernia furfuracae in streptozotocin (STZ)-induced diabetes. In experimental design, control or diabetic rats were either untreated or treated with aqueous lichen extracts (250-500 mg/kg /day) for 2 weeks starting at 72 h after STZ injection. On day 14, animals were anaesthetized, and metabolic and biochemical parameters were appreciated between control and treatment groups. The histopathology of liver was examined using three different staining methods: hematoxylin-eosin (H&E), periodic acid Schiff (PAS), and reticulin and Sudan Black B. Our experimental data showed that increasing doses of C. islandica and P. furfuracae alone did not have any detrimental effects on studied parameters and the malondialdehyde level of liver. C. islandica extract showed positive results for antioxidant capacity compared to doses of P. furfuracae extract. However, the protective effect of C. islandica extract on diabetes-induced disorders and hepatic damages is still unclear. Moreover, unfortunately, animals subjected to DM therapy did not benefit from the usage of increasing lichen doses due to their unchanged antioxidant activity in tissues. The results obtained in present study suggested that C. islandica and P. furfuracae is safe but the power of these is limited because of intensive oxidative stress in liver of type 1 diabetic rats. It is also implied that C. islandica extract is especially suitable for different administration routes in DM animals.
The Carvacrol Ameliorates Acute Pancreatitis-Induced Liver Injury Via Antioxidant Response
(Springer, 2016) Bakir, Murat; Geyikoglu, Fatime; Colak, Suat; Turkez, Hasan; Bakir, Tulay Ozhan; Hosseinigouzdagani, Mirkhalil
Acute pancreatitis (AP) may cause significant persistent multi-organ dysfunction. Carvacrol (CAR) possesses a variety of biological and pharmacological properties. The aim of the present study was to analyze the hepatic protection of CAR on AP induced by cerulein and to explore the underlying mechanism using in vivo studies. The rats were randomized into groups to receive (1) no therapy; (2) 50 A mu g/kg cerulein at 1-h intervals by four intraperitoneal injection (i.p.); (3) 50, 100 and 200 mg/kg CAR by one i.p.; and (4) cerulein + CAR after 2 h of cerulein injection. 12 h later, serum was provided to assess the blood AST, ALT and LDH values. Also, liver tissues were obtained for histological and biochemical measurements. Liver oxidative stress markers were evaluated by changes in the amount of lipid peroxides measured as MDA and changes in tissue antioxidant enzyme levels, SOD, CAT and GSH-Px. Histopathological examination was performed using scoring systems. Oxidative damage to DNA was quantitated in studied tissues of experimental animals by measuring the increase in 8-hydroxydeoxyguanosine (8-OHdG) formations. We found that the increasing doses of CAR decreased pancreatitis-induced MDA and 8-OH-dG levels. Moreover, the liver SOD, CAT and GSH-Px activities in the AP + CAR group were higher than that of the rats in the AP group. In the treatment groups, AST, ALT and LDH were reduced. Besides, necrosis, coagulation and inflammation in the liver were alleviated (p < 0.05). We suggest that CAR could be a safe and potent new drug candidate for treating AP through its antioxidative mechanism of action for the treatment of a wide range of disorders related to hepatic dysfunction.
Carvacrol Modulates Oxidative Stress and Decreases Cell Injury in Pancreas of Rats with Acute Pancreatitis
(Springer, 2016) Kilic, Yeliz; Geyikoglu, Fatime; Colak, Suat; Turkez, Hasan; Bakir, Murat; Hsseinigouzdagani, Mirkhalil
Acute pancreatitis (AP) is considered as major problem around the world and the incidence of AP is increasing. Carvacrol (CAR), a monoterpenic phenol, has good antioxidant activity. This in vivo study was designed to evaluate whether CAR provide protection against AP that developed by pancreas injury. The rats were randomised into groups to receive (I) no therapy; (II) 50 A mu g/kg cerulein at 1 h intervals by four intraperitonally (i.p.) injections; (III) 50, 100 and 200 mg/kg CAR by one i.p. injection; and (IV) cerulein plus CAR after 2 h of cerulein administration. 12 h later, serum samples were obtained to assess pancreatic function, the lipase and amylase values. The oxidative stress markers were evaluated by changes in the amount of lipid peroxides measured as malondialdehyde (MDA) and changes in main tissue antioxidant enzyme levels including SOD, CAT and GSH-PX. Histopathological examination was performed using scoring systems. Additionally, oxidative DNA damage was determined by measuring the increases of 8-hydroxy-deoxyguanosine (8-OH-dG) formations. We found that the increasing doses of CAR decreased AP-induced MDA and 8-OH-dG levels. Moreover, the pancreas antioxidant enzyme activities were higher than that of the rats in the AP group when compared to the AP plus CAR group. In the treatment groups, the lipase and amylase were reduced. Besides, histopathological findings in the pancreatic tissue were alleviated (p < 0.05). We suggest that CAR could be a safe and potent new drug candidate for treating AP through its antioxidative mechanism of action for the treatment of a wide range of disorders related to pancreas.
Effect of Oleuropein Against Chemotherapy Drug-Induced Histological Changes, Oxidative Stress, and DNA Damages in Rat Kidney Injury
(Food & Drug Administration, 2017) Geyikoglu, Fatime; Emir, Murat; Colak, Suat; Koc, Kubra; Turkez, Hasan; Bakir, Murat; Ozek, Nihal Simsek
Cisplatin-based chemotherapy is responsible for a large number of renal failures, and it is still associated with high rates of mortality today. Oleuropein (OLE) presents a plethora of pharmacological beneficial properties. In this study we investigated whether OLE could provide sufficient protection against cisplatin-induced nephrotoxicity. With this aim, Sprague-Dawley rats were divided into eight groups: control; 7 mg/kg/d cisplatin, 50 mg/kg, 100 mg/kg, and 200 mg/kg OLE; and treatment with OLE for 3 days starting at 24 hours following cisplatin injection. After exposure to the chemotherapy agent and OLE, oxidative DNA damage was quantitated in the renal tissue of experimental animals by measuring the amount of 8-hydroxy-20-deoxyguanosine (8-OHdG) adducts. Malondialdehyde (MDA) level, total oxidative stress (TOS), and total antioxidant status (TAS) were assessed to determine the oxidative injury in kidney cells. The histology of the kidney was examined using four different staining methods: hematoxylin-eosin (H& E), periodic acid Schiff (PAS), Masson trichrome, and amyloid. In addition, the blood urea nitrogen (BUN), uric acid (UA), and creatinine (CRE) levels were established. Our experimental data showed that tissue 8OHdG levels were significantly higher in the cisplatin group when compared to the control group. The glomerular cells were sensitive to cisplatin as tubular cells. In addition, treatment with cisplatin elevated the levels of BUN, UA, CRE, and TOS, but lowered the level of TAS compared to the control group. The OLE therapy modulated oxidative stress in order to restore normal kidney function and reduced the formation of 8-OHdG induced by cisplatin. Furthermore, the OLE treatment significantly reduced pathological findings in renal tissue. We demonstrate for the first time that OLE presents significant cytoprotective properties against cisplatin-induced genotoxicity by restoring the antioxidant system of the renal tissue. According to our findings, OLE is a promising novel natural source for the prevention of serious kidney damage in current chemotherapies. Copyright (C) 2016, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. This is an open access article under the CC BY-NC-ND license.
The Effects of Cetraria Islandica and Pseudevernia Furfuracea Extracts in Normal and Diabetic Rats
(Sage Publications Inc, 2015) Bakir, Tulay Ozhan; Geyikoglu, Fatime; Colak, Suat; Turkez, Hasan; Aslan, Ali; Bakir, Murat
Lichens are symbiotic organisms composed of a fungus joined to a photosynthesizing partner that can be either an alga or a cyanobacterium. They can be used as a novel bioresource for natural antioxidants. However, there is also a need for further studies to validate the lichens used in medicinal remedies. This study covers a previously unrecognized effects of Cetraria islandica (CIAE) and Pseudeverniafurfuracea (PFAE) in streptozotocin (STZ)-induced diabetes. In experimental design, control or diabetic rats were either untreated or treated with aqueous lichen extracts (250-500 mg/kg/day) for 2 weeks starting at 72 h after STZ injection. On day 14, animals were anesthetized, metabolic and biochemical parameters were appreciated between control and treatment groups. The histopathology of kidney was examined using four different staining methods: hematoxylin-eosin (H&E), periodic acid-Schiff (PAS), Masson trichrome and Congo red. Our experimental data showed that increasing doses of CIAE and PFAE did not have any detrimental effects on the studied parameters and the malondialdehyde level of kidney. CIAE extract showed prominent results compared to doses of PFAE extract for antioxidant capacity. However, the protective effect of CIAE extract was inadequate on diabetes-induced disorders and kidney damages. Moreover, animals subjected to diabetes mellitus (DM) therapy did not benefit unfortunately from the usage of increasing lichen doses due to their unchanged antioxidant activity to tissue. The results obtained in present study suggested that CIAE and PFAE are safe but the power of these is limited because of the intensive oxidative stress in kidney of type 1 diabetic rats. It is also implied that CIAE extract is especially suitable for different administration routes in DM.
The Efficacy of Carvacrol on Renal Damage in Rats with Acute Pancreatitis
(Taylor & Francis Ltd, 2014) Hsseinigouzdagani, Mirkhalil; Geyikoglu, Fatime; Colak, Suat; Turkez, Hasan; Bakir, Tuelay Ozhan; Bakir, Murat
The carvacrol is thought to promote optimal health via its antioxidant and free radical scavenging effects. The aim of our present study was to investigate the efficacy of carvacrol on the development of kidney injury in acute pancreatitis model (AP) induced by cerulein and to explore the underlying mechanism. The rats were randomised into groups to receive (I) no therapy; (II.) 50 mu g/kg cerulein at 1-h intervals by four intraperitonally injection (i.p.); (III) 50, 100 and 200 mg/kg carvacrol by one i.p.; and (IV) cerulein+carvacrol after 2 h of cerulein injection. 12 h later, serum was provided to assess the blood urea nitrogen (BUN), creatinine (CRE) and uric acid (UA) values. Also, renal tissues were obtained for histological and biochemical measurements. Kidney oxidative stress markers were evaluated by changes in the amount of lipid peroxides measured as malondialdehyde (MDA) and changes in tissue antioxidant enzyme levels, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX). Histopathological examination was performed using scoring systems. We found that the increasing doses of carvacrol decreased pancreatitis-induced MDA levels. Moreover, the renal SOD, CAT and GSH-Px activities in the AP+carvacrol group were higher than that of the rats in the AP group. In the treatment groups, the BUN, CRE and UA were reduced. Besides, necrosis, coagulation and inflammation in the kidney were alleviated (p < 0.05). Finally, the magnitude of the protective effect on kidney is certain, and 200 mg/kg carvacrol is an effective theraphy for oxidative stress caused by AP.
Evaluating the Toxic and Beneficial Effects of Lichen Extracts in Normal and Diabetic Rats
(Sage Publications Inc, 2016) Colak, Suat; Geyikoglu, Fatime; Bakir, Tulay Ozhan; Turkez, Hasan; Aslan, Ali
Lichens can be used as a novel bioresource for natural antioxidants. However, there is need for further investigations to validate the lichens used in medicinal remedies. In this study, the effects of Cetraria islandica and Pseudevernia furfuracae lichen species in streptozotocin (STZ)-induced diabetes were evaluated. Diabetic rats were treated with aqueous lichen extracts (250 and 500 mg/kg/day) for 2 weeks starting at 72 h after STZ injection. On the 14th day, animals were anesthetized, and then metabolic and biochemical parameters were evaluated between control and treatment groups. Pancreatic histology and -cell mass were examined by hematoxylin and eosin and insulin immunohistochemistry stainings. Our findings revealed that these lichen species could be used safely in this dose range. In addition, C. islandica extracts showed prominent results compared to the doses of P. furfuracae extract for antioxidant capacity. However, the protectivity of C. islandica extract was inadequate against diabetes-induced pancreatic damages via forming oxidative stress. In conclusion, the usage of C. islandica might serve for early intervening in the risk reduction of type 1 diabetes.
Oleuropein Ameliorates Cisplatin-Induced Hematological Damages Via Restraining Oxidative Stress and DNA Injury
(Springer India, 2017) Geyikoglu, Fatime; Colak, Suat; Turkez, Hasan; Bakir, Murat; Koc, Kubra; Hosseinigouzdagani, Mir Khalil; Sonmez, Merve
The prevalence of cancer, in the world is increasing steadily. Despite intense research efforts, no approved therapy is yet available. Cisplatin is a chemotherapeutic drug but induces acute tissue injury. Oleuropein (OLE) is a major phenolic compound and used as a possible natural antioxidant, antimicrobial, and anticancer agent. We hypothesized that antioxidant activity of OLE may decrease cisplatin-induced oxidative stress and prevent to the development of chemotherapeutic complications including abnormality in hematological condition. Male Sprague Dawley rats were used in the experiments. Rats were randomly assigned to one of eight groups: control group; group treated with i.p. injection in a single dose of 7 mg/kg/day cisplatin; groups treated with 50, 100 and 200 mg/kg/day OLE (i.p.); and groups treated with OLE for 3 days starting at 24 h following cisplatin injection. First, hematological assessment was appreciated between control and experimental groups. Second, total oxidative stress (TOS) and total antioxidant capacity (TAC) levels of blood were measured by biochemical studies. In addition to this, oxidative DNA damage was determined by measuring as increases in 8-hydroxy-deoxyguanosine (8-OH-dG) adducts. The treatment with cisplatin elevated the TOS and 8-OH-dG levels that were then reversed by OLE. Reductions in antioxidant capacity with respect to corresponding controls were also restored by OLE treatment. These findings suggest that the OLE treatment against cisplatin-induced toxicity improves the function of blood cells and helps them to survive in the belligerent environment created by free radicals.