Bünyamin Özgeriş

Bio: Bünyamin Özgeriş is an academic researcher from Erzurum Technical University. The author has contributed to research in topics: Carbonic anhydrase & Carbonic Anhydrase I. The author has an hindex of 6, co-authored 13 publications receiving 345 citations. Previous affiliations of Bünyamin Özgeriş include Atatürk University.

Antioxidant Activity, Acetylcholinesterase, and Carbonic Anhydrase Inhibitory Properties of Novel Ureas Derived from Phenethylamines.

Abstract: A series of ureas derived from phenethylamines were synthesized and evaluated for human carbonic anhydrase (hCA) I and II, acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) enzyme inhibitory activities and antioxidant properties. The ureas were synthesized from the reactions of substituted phenethylamines with N,N-dimethylcarbamoyl chloride; then, the synthesized compounds were converted to their corresponding phenolic derivatives via O-demethylation. hCA I and II were effectively inhibited by the newly synthesized compounds, with Ki values in the range of 0.307-0.432 nM for hCA I and 0.149-0.278 nM for hCA II. On the other hand, the Ki parameters of these compounds for AChE and BChE were determined in the range of 0.129-0.434 and 0.095-0.207 nM, respectively. Phenolic ureas also showed good antioxidant activities.

The human carbonic anhydrase isoenzymes I and II (hCA I and II) inhibition effects of trimethoxyindane derivatives.

Abstract: Carbonic anhydrases (CAs, EC 4.2.1.1) had six genetically distinct families described to date in various organisms. There are 16 known CA isoforms in humans. Human CA isoenzymes I and II (hCA I and hCA II) are ubiquitous cytosolic isoforms. Acetylcholine esterase (AChE. EC 3.1.1.7) is a hydrolase that hydrolyzes the neurotransmitter acetylcholine relaying the signal from the nerve. In this study, some trimethoxyindane derivatives were investigated as inhibitors against the cytosolic hCA I and II isoenzymes, and AChE enzyme. Both hCA isozymes were inhibited by trimethoxyindane derivatives in the low nanomolar range. These compounds were good hCA I inhibitors (Kis in the range of 1.66-4.14 nM) and hCA II inhibitors (Kis of 1.37-3.12 nM) and perfect AChE inhibitors (Kis in the range of 1.87-7.53 nM) compared to acetazolamide as CA inhibitor (Ki: 6.76 nM for hCA I and Ki: 5.85 nM for hCA II) and Tacrine as AChE inhibitor (Ki: 7.64 nM).

Synthesis and inhibitory properties of some carbamates on carbonic anhydrase and acetylcholine esterase

Abstract: A series of carbamate derivatives were synthesized and their carbonic anhydrase I and II isoenzymes and acetylcholinesterase enzyme (AChE) inhibitory effects were investigated. All carbamates were synthesized from the corresponding carboxylic acids via the Curtius reactions of the acids with diphenyl phosphoryl azide followed by addition of benzyl alcohol. The carbamates were determined to be very good inhibitors against for AChE and hCA I, and II isoenzymes. AChE inhibition was determined in the range 0.209-0.291 nM. On the other hand, tacrine, which is used in the treatment of Alzheimer's disease possessed lower inhibition effect (Ki: 0.398 nM). Also, hCA I and II isoenzymes were effectively inhibited by the carbamates, with inhibition constants (Ki) in the range of 4.49-5.61 nM for hCA I, and 4.94-7.66 nM for hCA II, respectively. Acetazolamide, which was clinically used carbonic anhydrase (CA) inhibitor demonstrated Ki values of 281.33 nM for hCA I and 9.07 nM for hCA II. The results clearly showed that AChE and both CA isoenzymes were effectively inhibited by carbamates at the low nanomolar levels.

Design, synthesis, characterization, and biological evaluation of nicotinoyl thioureas as antimicrobial and antioxidant agents.

Abstract: Addressed herein a series of thioureas starting from various amines and nicotinic acid have been synthesized. Notably, thiourea based scaffolds are increasingly employed in medicinal chemistry owing to their tunable physicochemical and structural properties. As well-known from the literature, the pyridine ring contains various biological properties, especially antimicrobial activity. Therefore, we performed the synthesis of biologically important thiourea derivatives containing pyridine ring. The structures of the synthesized compounds were characterized by 1H NMR, 13C NMR and FT-IR. In the second part of the study, newly synthesized compounds were also tested in order to demonstrate their antimicrobial and antioxidant properties. All compounds exhibited moderate activity against all tested bacteria known to cause nosocomial infections, which have acquired resistance to many antibiotics, as compared to the standard antibiotics and also strong antioxidant properties. Therefore, they can be evaluated as possible seeds of agents in the treatment of bacterial infections and many health problems related to aging such as cancer, and neurodegenerative diseases.

Antioxidants and antioxidant methods: an updated overview

Abstract: Antioxidants had a growing interest owing to their protective roles in food and pharmaceutical products against oxidative deterioration and in the body and against oxidative stress-mediated pathological processes. Screening of antioxidant properties of plants and plant-derived compounds requires appropriate methods, which address the mechanism of antioxidant activity and focus on the kinetics of the reactions including the antioxidants. Many studies evaluating the antioxidant activity of various samples of research interest using different methods in food and human health have been conducted. These methods are classified, described, and discussed in this review. Methods based on inhibited autoxidation are the most suited for termination-enhancing antioxidants and for chain-breaking antioxidants, while different specific studies are needed for preventive antioxidants. For this purpose, the most common methods used in vitro determination of antioxidant capacity of food constituents were examined. Also, a selection of chemical testing methods was critically reviewed and highlighted. In addition, their advantages, disadvantages, limitations and usefulness were discussed and investigated for pure molecules and raw extracts. The effect and influence of the reaction medium on the performance of antioxidants are also addressed. Hence, this overview provides a basis and rationale for developing standardized antioxidant methods for the food, nutraceuticals, and dietary supplement industries. In addition, the most important advantages and shortcomings of each method were detected and highlighted. The chemical principles of these methods are outlined and critically discussed. The chemical principles of methods of 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulphonate) radical (ABTS·+) scavenging, 1,1-diphenyl-2-picrylhydrazyl (DPPH·) radical scavenging, Fe3+-Fe2+ transformation assay, ferric reducing antioxidant power (FRAP) assay, cupric ions (Cu2+) reducing power assay (Cuprac), Folin-Ciocalteu reducing capacity (FCR assay), peroxyl radical (ROO·), superoxide radical anion (O2·-), hydrogen peroxide (H2O2) scavenging assay, hydroxyl radical (OH·) scavenging assay, singlet oxygen (1O2) quenching assay, nitric oxide radical (NO·) scavenging assay and chemiluminescence assay are outlined and critically discussed. Also, the general antioxidant aspects of main food components were discussed by a number of methods, which are currently used for the detection of antioxidant properties of food components. This review consists of two main sections. The first section is devoted to the main components in the food and pharmaceutical applications. The second general section comprises some definitions of the main antioxidant methods commonly used for the determination of the antioxidant activity of components. In addition, some chemical, mechanistic and kinetic basis, and technical details of the used methods are given.

The Molecular Biology of Cancer

Abstract: The accumulation of knowledge associated with cancer biology continues to progress at a phenomenal rate; the electronic availability of research papers and news items makes access to new discoveries almost instantaneous. International meetings present opportunities to share scientific knowledge and develop collaborations, as well as fuelling competition between groups, to drive research forward. As a primary researcher or graduate student, the ability to adapt research projects to take advantage of new technological and scientific developments in the field of cancer biology requires a broad knowledge of subjects outside the primary areas of research. Similarly, an undergraduate or newcomer to the field must initially familiarise themselves with established principles before facing the daunting task of processing the vast amount of specialised knowledge available. The editors of The Molecular Biology of Cancer have identified the need for a book that assimilates critical aspects of cancer biology into a single resource to function as a reference tool and teaching aid applicable to both students and researchers alike. The book is divided into 18 chapters and a glossary. Each chapter is authored by experts in the field and is prefaced by a list of the key points covered in that section. The chapters are organised according to a common format; of particular note is the arrangement of the bibliographies at the end of each chapter where references are grouped according to the concepts discussed. This format facilitates navigation of the information presented in each section, allowing the book to be used as a reference tool. This is ideal for established cancer biologists requiring clarity of specific subjects as well as those using the book to learn topics from first principles. It is in catering to this dual audience that the book is particularly strong. The Introduction presents cancer as a genetic disease that requires the acquisition of the classical ‘hallmarks' by cancer cells to promote tumour development. Basic concepts are clearly presented in this chapter that would be redundant to an established cancer biologist but invaluable to a newcomer to the field and of great importance in the context of the book as a teaching resource. Chapter 2 considers the clinical features of lung, breast and prostate cancer and determines the context in which the molecular biology described in the subsequent chapters should be considered; namely, in terms of disease manifestation. The interplay between the environment and genetic lesions associated with cancer is considered in Chapter 3; the book then focuses on the molecular basis of the cellular processes relevant to the cancer cell. The mechanisms fundamental to the normal cell cycle and DNA replication are described in Chapter 4; Chapters 6, 7 and 10 discuss the role of oncogenes, tumour suppressor genes and genetic instability, respectively. Chapter 11 describes the role of epigenetic factors in gene expression and the influence of post-translational modifications on protein expression. There is, however, comparatively little discussion of the role of signal transduction in cancer development. The vast nature of this field makes consideration of every pathway impossible in this context but a more thorough overview could be achieved if a whole chapter were devoted to this topic. The RAS – MAPK pathway and PI3K – Akt pathway are highlighted as examples of critical signalling modules in cell growth as part of Chapter 5 but could be included on their own. This is especially relevant given the potential of signalling pathway components as drug targets. At times, the complex nature of the mechanisms and theories discussed necessitates detailed descriptions resulting in large blocks of text. However, large, monochrome figures clearly summarise these descriptions or are used in place of them where possible. Additional colour plates illustrate signalling pathways and clinical images that would be unclear in black and white. Information that is relevant to the chapter but would be incongruous in the main text, such as highlights of key experiments, is presented in additional text boxes. Tables are also used to present lists of information, such as protein classifications, in an organised format that would not be possible in the main text. The conclusion of each chapter summarises the topics covered and suggests questions that still remain in the field. Chapters 15, 16 and 17 address the issues of cancer diagnosis, treatment and patient care and set the book apart from a general molecular biology reference by considering the clinical implications of understanding this subject. Chapter 17 is especially poignant in its highly informative discussion of the management of the palliative care of cancer patients. The title of the book does not imply that these topics would be included; however, it is information I feel is essential to complete the comprehensive reference guide that the editors aimed to produce. The development of therapies specifically targeting the molecules responsible for the transformed phenotype demands a detailed understanding of the mechanisms behind normal cellular processes. This knowledge should not be gained at the expense of an appreciation of the impact that bench-based research has on the patient in hospital. An awareness of the human implications of gaps in our understanding of cancer development should drive research. The pace of cancer research means that the latest knowledge of highly specialised concepts is essential but, equally, the cross talk between different subject areas means a solid understanding is essential to take advantage of the plethora of new data available. Essentially, The Molecular Biology of Cancer is a book that can be used as an introduction to the subject as well as a platform on which to assimilate new information in the context of established principles. This book is applicable to both graduate and undergraduate students and, in the context of a research laboratory, this book would be an excellent resource as a reference guide for scientists at all levels.

Synthesis and Reactivity of Propargylamines in Organic Chemistry

Abstract: Propargylamines are a versatile class of compounds which find broad application in many fields of chemistry. This review aims to describe the different strategies developed so far for the synthesis of propargylamines and their derivatives as well as to highlight their reactivity and use as building blocks in the synthesis of chemically relevant organic compounds. In the first part of the review, the different synthetic approaches to synthesize propargylamines, such as A3 couplings and C–H functionalization of alkynes, have been described and organized on the basis of the catalysts employed in the syntheses. Both racemic and enantioselective approaches have been reported. In the second part, an overview of the transformations of propargylamines into heterocyclic compounds such as pyrroles, pyridines, thiazoles, and oxazoles, as well as other relevant organic derivatives, is presented.

Antioxidant and Antiradical Properties of Selected Flavonoids and Phenolic Compounds

Abstract: Phenolic compounds and flavonoids are known by their antioxidant properties and one of the most important sources for humans is the diet. Due to the harmful effects of synthetic antioxidants such as BHA and BHT, natural novel antioxidants have become the focus of attention for protecting foods and beverages and reducing oxidative stress in vivo. In the current study, we investigated the total antioxidant, metal chelating, Fe3+ and Cu2+ reduction, and free radical scavenging activities of some phenolic and flavonoid compounds including malvin, oenin, ID-8, silychristin, callistephin, pelargonin, 3,4-dihydroxy-5-methoxybenzoic acid, 2,4,6-trihydroxybenzaldehyde, and arachidonoyl dopamine. The antioxidant properties of these compounds at different concentrations (10–30 μg/mL) were compared with those of reference antioxidants such as BHA, BHT, α-tocopherol, and trolox. Each substance showed dose-dependent antioxidant activity. Furthermore, oenin, malvin, arachidonoyl dopamine, callistephin, silychristin, and 3,4-dihydroxy-5-methoxybenzoic acid exhibited more effective antioxidant activity than that observed for the reference antioxidants. These results suggest that these novel compounds may function to protect foods and medicines and to reduce oxidative stress in vivo.