Sedef Ziyanok-demirtas

Prof. Sedef Ziyanok-demirtas

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Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 September 2021 in Food Science and Technology
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Journal Article
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MGMetin Guldas
Metin Guldas
SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
YSYasemin Sahan
Yasemin Sahan
EYElif YILDIZ
Elif YILDIZ
OGOzan Gurbuz
Ozan Gurbuz
Graphical Abstract : TOC-Table of content. Abstract Spirulina produced in Turkey has a high antioxidant capacity determined by the three common methods (ABTS, CUPRAC, and DPPH). The major phenolics found in Spirulina were acacetin (53.62%) and pinocembrin (41.28%). The bio-accessibility values of the phenolic compounds in Spirulina were approximately 60%. PUFA’s are the significant antioxidant compounds to prevent lipid peroxidation. Spirulina has been found to reduce blood sugar and oxidative stress due probably to the high amount of ω-6 PUFA. By the treatment of Spirulina, the levels of antioxidant enzymes (GSH-Px and SOD) were increased 240 and 60% in the healthy rats, while 19 and 59% in the diabetics. In diabetic rats fed with Spirulina, glucose, triglyceride, total cholesterol levels in blood and malondialdehyde content in body tissues were decreased by 20, 31, 22 and up to 56%, respectively. In-vitro and in-vivo tests have shown that Spirulina has anti-hyperglycaemic, anti-hyperlipidaemia and antioxidative effects on diabetic rats.

2 March 2011 in Cell Biochemistry and Function
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Journal Article
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STSibel Taş
Sibel Taş
SCSerap Celikler
Serap Celikler
SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
ESEmre Sarandöl
Emre Sarandöl
MDMelahat Dirican
Melahat Dirican

26 April 2024 in Biomedicine & Pharmacotherapy
Verified
Journal Article
Open access
SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
Recent advances in diabetes treatment have primarily focused on insulin and hypoglycemic agents; however, there is growing interest in exploring herbal and synthetic alternatives. Numerous studies have highlighted the preventive effectiveness of regular plant consumption in managing chronic conditions, particularly diabetes. Hibiscus, a medicinal plant recognized in various cultures, is known for its diverse health benefits. This study investigated the impact of Hibiscus trionum on glycemic control and assessed its influence on glucose and insulin levels in diabetes-induced rats. The concentrations of antioxidant enzymes, particularly superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), were scrutinized across multiple body tissues (plasma, heart, muscle, liver, and kidney). The malondialdehyde (MDA) concentration, an indicator of lipid peroxidation, was examined in both plasma and tissue samples. Serum total cholesterol (TC), triglyceride (TG), aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels were evaluated. Diabetic Group (D) exhibited a significant decrease in body weight, increased fluid and food consumption, elevated blood glucose levels, and increased antioxidant enzyme activity. Moreover, the diabetic group also showed increased levels of MDA, TC, TG, AST, and ALT, along with reduced insulin levels, compared to the control group. A substantial improvement in all parameters impaired by diabetes was observed following the application of Hibiscus trionum (HTT) in the Diabetes+HTT group. The antioxidative stress-reducing, lipid peroxidation-improving, and hepatoprotective potential of Hibiscus trionum in mitigating diabetes-induced oxidative stress is noteworthy. These findings indicate that HTT supplementation has valuable beneficial effects in protecting against the harmful impacts of diabetes.

27 May 2024 in Life
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SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
Diabetes mellitus (DM) is a significant global health burden that necessitates the exploration of effective and accessible therapeutic options. Phytotherapy has played a vital role in healthcare, with plant extracts being integral to traditional medicinal practices. The therapeutic potential of Hibiscus syriacus (Rose of Sharon), a plant with a rich ethnobotanical history, in the management of DM and its associated complications was investigated. In this study, the therapeutic potential of Hibiscus syriacus L. extract (HSE) against DM in streptozotocin (STZ)-induced diabetic rats was assessed, focusing on its effects on glucose regulation, antioxidative defense, and liver protection. The administration of the HSE extract substantially reduced hyperglycemia and increased insulin production, with concurrent improvements in body weight and hydration. The enhanced activity of antioxidant enzymes, such as superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), suggests reduced oxidative stress, which is further supported by molecular docking results with the 3GTV superoxide dismutase enzyme, showing a binding energy of −6.3 kcal/mol. A decrease in MDA levels also indicates a reduction in oxidative stress. Notably, HSE treatment led to decreased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels and improved lipid profiles, indicating its hepatoprotective and lipid-modifying benefits. These findings support the inclusion of HSE as an adjunctive therapy in DM management strategies. This study promotes the consideration of Hibiscus syriacus L. therapeutic properties in global health contexts.

30 September 2025 in Doğu Karadeniz Sağlık Bilimleri Dergisi
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Journal Article
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SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
Diyabet ve kanser gerek gelişmiş gerekse de gelişmekte olan ülkelerde önemli halk sağlığı sorunlarıdır. Dünya Sağlık Örgütü verileri, diyabet prevalansının hızla arttığını ve bu artışın yalnızca kardiyovasküler komplikasyonlarla değil, malign hastalıklarla da ilişkili olabileceğini göstermektedir. Kanser ise dünya genelinde ölüme yol açan ikinci en yaygın hastalık grubudur ve çevresel, genetik ve yaşam tarzı faktörlerinden etkilenir. Epidemiyolojik ve moleküler çalışmalar, özellikle tip 2 diyabet hastalarında bazı kanser türlerinin daha sık görüldüğünü ortaya koymuştur. Obezite, fiziksel inaktivite, ileri yaş ve beslenme alışkanlıkları gibi ortak risk faktörlerinin yanı sıra hiperinsülinemi, kronik inflamasyon ve hiperglisemi gibi diyabete özgü patofizyolojik süreçler de kanser gelişimine katkıda bulunabilir. Diyabet tedavisinde kullanılan ilaçlar da bu ilişki açısından önemlidir. Metforminin bazı kanser türlerinde koruyucu olabileceği, insülin ve bazı insülin analoglarının ise uzun süreli kullanımda potansiyel risk artışı ile ilişkilendirilebileceği tartışılmaktadır. Bu derleme, mevcut literatürü inceleyerek diyabet ve kanser arasındaki çok yönlü ilişkileri değerlendirmeyi ve gelecekteki araştırmalara yön vermeyi amaçlamaktadır.

16 September 2024 in Online Türk Sağlık Bilimleri Dergisi
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SZSedef Ziyanok-demirtas
Sedef Ziyanok-demirtas
Objective: Diabetes mellitus (DM) accelerates oxidative stress beyond its broad effects on metabolic function, which has been linked to various chronic complications. This study investigated the antioxidative and therapeutic potential of Hibiscus syriacus (HSE) and Hibiscus trionum extracts (HTE), focusing on their effects on paraoxonase (PON) and arylesterase enzymes activity in diabetic rat models. Material and Methods: This study evaluated PON and ARE activities in 36 Wistar albino rats divided into the following groups: control (C), C+HSE, C+HTE, Diabetes (D), D+HSE, and D+HTE. The total phenolic content of HSE and HTE was determined using the Folin- Ciocalteu method, and their antioxidant activities were assessed using DPPH and CUPRAC tests. Results: HSE and HTE extracts have demonstrated significant increases in paraoxonase and arylesterase activities, which are crucial for cardiovascular protection and reducing oxidative stress in diabetes. Conclusions: This study highlights the potential of natural extracts in managing oxidative stress-related complications associated with diabetes and underscores the need to integrate such phytotherapeutic agents into broader diabetes care strategies. Future research should focus on confirming these findings in clinical settings and investigating the molecular processes responsible for the observed effects, potentially paving the way for innovative interventions for diabetes management.