Person: YALÇIN, AHMET SUHA
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YALÇIN
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AHMET SUHA
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Publication Open Access Anti-cancer effects of curcumin, quercetin and tea catechins(MARMARA UNIV, FAC PHARMACY, 2016-09-20) YALÇIN, AHMET SUHA; Yalcin, A. Suha; Yilmaz, Ayse Mine; Altundag, Ergul Mutlu; Kocturk, SemraPolyphenols are present in high amounts in all parts of plants including roots, seeds, flowers, leaves, branches and trunk as well as plant derived products such as tea, coffee and wine. Extensive amount of information is available on biological effects of polyphenols including antioxidant, anti-cancer, anti-inflammatory, anti-coagulant and anti-microbial activities. In recent years, researchers have turned their interest towards identifying molecular mechanisms underlying the anti-cancer effects of these compounds. However, the limited bioavailability of polyphenols and the existence of differences in cancer cells in terms of intracellular mechanisms affected has necessitated the use of specific approaches to individual cancer cell types as well as methods of increasing bioavailability. In this review, the structures, bioavailability, biological activities and molecular mechanisms of anti-cancer effects of curcumin, quercetin and tea catechins are discussed.Publication Metadata only Comparison of antioxidant capacity, protein profile and carbohydrate content of whey protein fractions(ELSEVIER SCI LTD, 2014) YALÇIN, AHMET SUHA; Onay-Ucar, Evren; Arda, Nazli; Pekmez, Murat; Yilmaz, Ayse Mine; Boke-Sarikahya, Nazli; Kirmizigul, Suheyla; Yalcin, A. SuhaWhey is used as an additive in food industry and a dietary supplement in nutrition. Here we report a comparative analysis of antioxidant potential of whey and its fractions. Fractions were obtained by size exclusion chromatography, before and after enzymatic digestion with pepsin or trypsin. Superoxide radical scavenging, lipid peroxidation inhibition and cupric ion reducing activities of different fractions were checked. Peptides were detected by SDS-PAGE and GC-MS was used to determine carbohydrate content of the fractions. All samples showed antioxidant activity and the second fraction of the trypsin hydrolysate showed the highest superoxide radical scavenging activity. CUPRAC value of this fraction was two-times higher than that of whey filtrate. The first fraction of the pepsin hydrolysate was the most effective inhibitor of lipid peroxidation. Each sample exhibited a different polypeptide profile. Different percentages of carbohydrates were identified in whey filtrate and in all second fractions, where galactose was the major component. (C) 2013 Elsevier Ltd. All rights reserved.Publication Open Access Imaging Reactive Oxygen Species-Induced Modifications in Living Systems(MARY ANN LIEBERT, INC, 2016-06) YALÇIN, AHMET SUHA; Maulucci, Giuseppe; Bacic, Goran; Bridal, Lori; Schmidt, Harald H. H. W.; Tavitian, Bertrand; Viel, Thomas; Utsumi, Hideo; Yalcin, A. Suha; De Spirito, MarcoSignificance: Reactive Oxygen Species (ROS) may regulate signaling, ion channels, transcription factors, and biosynthetic processes. ROS-related diseases can be due to either a shortage or an excess of ROS. Recent Advances: Since the biological activity of ROS depends on not only concentration but also spatiotemporal distribution, real-time imaging of ROS, possibly in vivo, has become a need for scientists, with potential for clinical translation. New imaging techniques as well as new contrast agents in clinically established modalities were developed in the previous decade. Critical Issues: An ideal imaging technique should determine ROS changes with high spatio-temporal resolution, detect physiologically relevant variations in ROS concentration, and provide specificity toward different redox couples. Furthermore, for in vivo applications, bioavailability of sensors, tissue penetration, and a high signal-to-noise ratio are additional requirements to be satisfied. Future Directions: None of the presented techniques fulfill all requirements for clinical translation. The obvious way forward is to incorporate anatomical and functional imaging into a common hybrid-imaging platform.Publication Metadata only Effect of different culture media on isolation and differentiation of dendritic cells(WALTER DE GRUYTER GMBH, 2015) YALÇIN, AHMET SUHA; Yilmaz, Ayse Mine; Altundag, Ergul Mutlu; Gedik, Gulsah; Kocturk, Semra; Yalcin, A. Suha; Taga, YavuzObjective: Dendritic cells (DCs) are members of the mammalian immune system and are considered to be the most powerful antigen presenting cells. They are responsible for the induction of T-cells or T-cell dependent immunity and tolerance. In this study we have investigated the effect of different serum supplements on generation and yield of mature dendritic cells isolated from peripheral blood mononuclear cells. Methods: Three different serum supplements (10% Fetal Bovine Serum, 1% Human Serum Albumin and 1% autologous serum) were compared with serum-free media to identify the role and importance of serum supplements on DC cultivation. Effect of different media on maturation signs (CD40, CD80, CD86, CD209a) and cytokine release (TNF-alpha, IL-10, IL-12, IL-6) was examined. Results: DCs generated in serum-free media was similar to those of cells in medium with autologous serum. Few dendritic-like cells were observed in fetal bovine serum and human serum albumin. The effect of different media on maturation of DCs was compared phenotypically and increased expression of CD80, CD86 and CD209a identified maturation and yield of DCs. Conclusion: Our results suggest that serum free media can be used to overcome potential drawbacks associated with different serum containing supplements.Publication Metadata only Redox Regulation and Cancer Therapy(BENTHAM SCIENCE PUBL LTD, 2018) YALÇIN, AHMET SUHA; Yalcin, A. Suha; Karademir, BetulPublication Metadata only Dietary whey supplementation in experimental models of wound healing(VERLAG HANS HUBER, 2008) YALÇIN, AHMET SUHA; Ogunc, Ayliz Velioglu; Manukyan, Manuk; Cingi, Asim; Eksioglu-Demiralp, Emel; Aktan, A. Odemir; Yalcin, A. SuhaWhey is a dairy product containing milk serum proteins with diverse biological effects. In this study, the effect of dietary whey supplementation on wound healing was investigated. Rats were fed a standard or whey-supplemented diet for three weeks. Wound healing parameters, glutathione, and lipid peroxide levels were determined three days after the application of two different models of wound healing, i.e. laparotomy and colonic anastomosis. Dietary whey supplementation significantly increased glutathione levels and suppressed lipid peroxidation after experimental laparotomy and colonic anastomosis. Bursting pressures, hydroxyproline, and cytokine levels were not changed. Our results show that dietary whey supplementation increases glutathione synthesis and cellular antioxidant defense. Long-term effects of whey feeding on wound healing remains to be investigated.Publication Metadata only Emerging therapeutic potential of whey proteins and peptides(BENTHAM SCIENCE PUBL LTD, 2006) YALÇIN, AHMET SUHA; Yalcin, A. SuhaWhey is a natural by-product of cheese making process. Bovine milk has about 3.5% protein, 80% of which are caseins and the remaining 20% are whey proteins. Whey proteins contain all the essential amino acids and have the highest protein quality rating among other proteins. Advances in processing technologies have led to the industrial production of different products with varying protein contents from liquid whey. These products have different biological activities and functional properties. Also recent advances in processing technologies have expanded the commercial use of whey proteins and their products. As a result, whey proteins are used as common ingredients in various products including infant formulas, specialized enteral and clinical protein supplements, sports nutrition products, products specific to weight management and mood control. This brief review intends to focus on scientific evidence and recent findings related to the therapeutic potential of whey proteins and peptides.Publication Open Access Effects of aminoguanidine on lipid and protein oxidation in diabetic rat kidneys(2002) YALÇIN, AHMET SUHA; Yavuz D.G., Küçükkaya B., Ersöz H.Ö., Yalçin A.S., Emerk K., Akalin S.Nonenzymatic glycation of tissue and plasma proteins may stimulate the production of oxidant and carbonyl stress in diabetes. The aim of this study was to evaluate the effects of aminoguanidine (AG) on lipid peroxidation, protein oxidation and nitric oxide (NO) release in diabetic rat kidneys. After induction of diabetes with streptozotocin, female Wistar rats were divided into 2 groups. Group DAG (n=9) rats were given AG hydrogen carbonate (1 g/L) in drinking water and group D (n=8) was diabetic control rats given only tap water. Group H (n=8) was followed as healthy controls. At the end of an 8 week period, NO release, lipid and protein oxidation were determined in kidney tissues. NO release was significantly lower in diabetic rats compared with healthy controls (p<0.05). Lipid peroxidation was significantly high in group D (3.9 ± 0.3 nmol MDA/g tissue) compared with the group DAG (2.6 ± 0.1 nmol MDA/g tissue, p<0.01) and group H (2.4 ± 0.2 nmol MDA/g tissue). Protein oxidation was significantly higher in diabetics than healthy controls (563.8 ± 23.9, 655.8 ± 7.2, 431.5 ± 8.8 mmol carbonyl/g tissue for group DAG, D and H, respectively, p< 0.05). A positive correlation between albuminuria and thiobarbituric acid reactive substance (TBARS) levels (r= 0.54, p<0.005) and carbonyl content (r=0.70, p<0.0005) in kidney homogenate were observed. Although AG treatment had no effect on NO release, it significantly decreased lipid peroxidation in diabetic rat cortices. Consequently increased lipid peroxidation -as well as- protein oxidation could be involved in the pathogenesis of diabetic albuminuria.Publication Metadata only Synergistic Induction of Apoptosis by Quercetin and Curcumin in Chronic Myeloid Leukemia (K562) Cells: II. Signal Transduction Pathways Involved(ROUTLEDGE JOURNALS, TAYLOR & FRANCIS LTD, 2021) YALÇIN, AHMET SUHA; Altundag, Ergul Mutlu; Yilmaz, Ayse Mine; Serdar, Belgin Sert; Jannuzzi, Ayse Tarbin; Kocturk, Semra; Yalcin, A. SuhaFlavonoids are phenolic substances with chemo-preventive and chemotherapeutic properties. They are widely found in fruits and vegetables. The polyphenols quercetin and curcumin have antioxidant, anti-inflammatory, anti-carcinogenic, and pro-apoptotic properties. They were successfully used against different human cancers, especially chronic myeloid leukemia cancer cells. We have previously investigated anti-proliferative and apoptotic effects of quercetin and curcumin combination in K562 cells. Our data showed that they had beneficial synergistic effects. Based on these findings, we aimed to clarify signaling pathways involved in synergistic combination treatment with quercetin and curcumin in these cells. Proteins were investigated by Western blotting and by confocal microscopy. Changes in several genes in 10 different pathways related to cell proliferation, apoptosis, cell cycle, inflammation, hypoxia and oxidative stress were observed. Combination of quercetin and curcumin was effective on genes that were particularly related to p53, NF-kappa B and TGF-alpha pathways. Down-regulatory (CDKN1B, AKT1, IFN-gamma) and up-regulatory (BTG2, CDKN1A, FAS) effects on genes and related protein expressions may provide a multi-targeted therapy potential for chronic myeloid leukemia cancer cells without affecting healthy cells.Publication Open Access Whey proteins: targets of oxidation, or mediators of redox protection(TAYLOR & FRANCIS LTD, 2019-08-12) YALÇIN, AHMET SUHA; Giblin, Linda; Yalcin, A. Suha; Bicim, Gokhan; Kramer, Anna C.; Chen, Zhifei; Callanan, Michael J.; Arranz, Elena; Davies, Michael J.Bovine whey proteins are highly valued dairy ingredients. This is primarily due to their amino acid content, digestibility, bioactivities and their processing characteristics. One of the reported bioactivities of whey proteins is antioxidant activity. Numerous dietary intervention trials with humans and animals indicate that consumption of whey products can modulate redox biomarkers to reduce oxidative stress. This bioactivity has in part been assigned to whey peptides using a range of biochemical or cellular assays in vitro. Superimposing whey peptide sequences from gastrointestinal samples, with whey peptides proven to be antioxidant in vitro, allows us to propose peptides from whey likely to exhibit antioxidant activity in the diet. However, whey proteins themselves are targets of oxidation during processing particularly when exposed to high thermal loads and/or extensive processing (e.g. infant formula manufacture). Oxidative damage of whey proteins can be selective with regard to the residues that are modified and are associated with the degree of protein unfolding, with alpha-Lactalbumin more susceptible than beta-Lactoglobulin. Such oxidative damage may have adverse effects on human health. This review summarises how whey proteins can modulate cellular redox pathways and conversely how whey proteins can be oxidised during processing. Given the extensive processing steps that whey proteins are often subjected to, we conclude that oxidation during processing is likely to compromise the positive health attributes associated with whey proteins.
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