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Featured researches published by Faik Ahmet Ayaz.


Clinical Toxicology | 2008

Clinical review of grayanotoxin/mad honey poisoning past and present

Abdulkadir Gunduz; Suleyman Turedi; Robert Michael Russell; Faik Ahmet Ayaz

Grayanotoxin is a naturally occurring sodium channel toxin which enters the human food supply by honey made from the pollen and nectar of the plant family Ericaceae in which rhododendron is a genus. Grayanotoxin/mad honey poisoning is a little known, but well studied, cholinergic toxidrome resulting in incapacitating and, sometimes, life-threatening bradycardia, hypotension, and altered mental status. Complete heart blocks occur in a significant fraction of patients. Asystole has been reported. Treatment with saline infusion and atropine alone is almost always successful. A pooled analysis of the dysrhythmias occurring in 69 patients from 11 different studies and reports is presented. The pathophysiology, signs, symptoms, clinical course, and treatment of grayanotoxin/mad honey poisoning are discussed. In the nineteenth century grayanotoxin/mad honey poisoning was reported in Europe and North America. Currently, documented poisoning from locally produced honey in Europe or North America would be reportable. Possible reasons for this epidemiologic change are discussed.


European Journal of Medicinal Chemistry | 2010

DNA binding, antioxidant and antimicrobial activities of homo- and heteronuclear copper(II) and nickel(II) complexes with new oxime-type ligands.

Ahmet Colak; Ülkü Terzi; Melek Col; Şengül Alpay Karaoğlu; Serdar Karaböcek; Aslıgül Küçükdumlu; Faik Ahmet Ayaz

Some homo- and heteronuclear Cu(II) and Ni(II) complexes of new oxime-type ligands were tested against several pathogenic microorganisms to assess their antimicrobial potentials. The antimicrobial activities of complexes were evaluated in terms of minimum inhibitory concentration (MIC; μg/μL) and it was observed that the complexes possess moderate antimicrobial properties. The binding of the complexes with DNA were also investigated by using UV-Vis spectroscopy. It was seen that three of the complexes could bind to DNA through an intercalative mode while the other complexes could have other mechanisms. Furthermore, the antioxidant efficiencies of the metal complexes were determined by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavening activities. Due to the observed IC(50) values, they are potential drugs to eliminate the radicals.


Food Chemistry | 2003

Changes in sugars, organic acids and amino acids in medlar (Mespilus germanica L.) during fruit development and maturation

Robert H. Glew; Faik Ahmet Ayaz; Carlos Sanz; Dorothy J. VanderJagt; Hsiao-Ling Huang; L.-T. Chuang; Miroslav Strnad

Abstract The contents of sugars, organic acids, and amino acids (after acid hydrolysis) were determined during development and maturation of medlar (Mespilus germanica L.) fruit from 39 days after full bloom (DAF) until 2 weeks after the beginning of fruit drop (161 DAF). Fructose, glucose and sucrose were identified as the principal sugars and their levels varied remarkably during development. The fructose level increased continually through development reaching its maximum by 161 DAF (1200 mg/100 g fresh weight) while the increase of sucrose reached maximum at 131 DAF and had decreased at 161 DAF. After some fluctations at 69 DAF, glucose level remained high (686 mg/100 g fresh weight) at 161 DAF, when compared with Stage IV (131 DAF). While the level of malic acid increased continually, the ascorbic acid level decreased dramatically through fruit development; both acids reached their maximum and minimum levels at 161 DAF, i.e. 428 and 8.4 mg/100 g fresh weight, respectively. The total amino acid composition also changed in decreasing trend throughout development and remained low at 161 DAF. In the ripe fruit, glutamate and aspartate were the major amino compounds identified. These changes in the identified compounds can be related to the metabolic activity during fruit development and maturation.


Journal of Agricultural and Food Chemistry | 2009

CHARACTERIZATION OF ANTHOCYANINS IN CAUCASIAN BLUEBERRIES (VACCINIUM ARCTOSTAPHYLOS L.) NATIVE TO TURKEY

Anja K. Lätti; Pirjo Kainulainen; Sema Hayirlioglu-Ayaz; Faik Ahmet Ayaz; Kaisu R. Riihinen

High-performance liquid chromatography (HPLC) combined with diode array (DAD) and electrospray ionization mass spectrometric (ESI-MS) detections were used to characterize anthocyanins in the berries of Vaccinium arctostaphylos L. The dark purple-black berries were collected from five Caucasian blueberry populations in northeastern Turkey. The HPLC-DAD profile consisted of 19 anthocyanin peaks, but HPLC-ESI-MS revealed fragment ion patterns of 26 anthocyanins. Delphinidin, cyanidin, petunidin, peonidin, and malvidin were all glycosylated with four different monosaccharide moieties (galactose, glucose, arabinose, and xylose) with the first two also conjugated with rhamnose. Furthermore, anthocyanidin disaccharides, tentatively identified as anthocyanidin sambubiosides, were characteristic for these berries. The mean content of the total anthocyanins was 1420 mg/100 g dry weight. The most predominant anthocyanidins were delphinidin (41%), petunidin (19%), and malvidin (19%). Glucose was the most typical (61%) sugar moiety. This study revealed that wild Caucasian blueberries contain an abundance of bioactive anthocyanins and thus are ideal for various functional food purposes.


Plant Foods for Human Nutrition | 2009

Nutrient Content of Carob Pod ( Ceratonia siliqua L.) Flour Prepared Commercially and Domestically

Faik Ahmet Ayaz; Hülya Torun; Robert H. Glew; Zehra Duygu Bak; L.-T. Chuang; Jack M. Presley; Ronnie Andrews

Although the fruit of the carob tree (Ceratonia siliqua L. Fabaceae) is nutritious and widely available in Turkey, especially in West and South Anatolia, much remains to be learned about its nutrient composition. The main goal of our study was to determine if there are differences in the content of certain nutrients in commercially-prepared carob flour (CPCP) and domestic or home-prepared carob powder (HPCP). Sucrose was the main sugar in CPCP and HPCP. Total protein was 40% lower in CPCP than HPCP due mainly to decreases in the content of several essential amino acids. However, except for lysine in CPCP, HPCP and CPCP compared favourably to a WHO protein standard. There were large differences in terms of their content of the two essential fatty acids, linoleic and α-linolenic acid, and the linoleic acid/α-linolenic acid ratio was 3.6 for CPCP, and 6.1 for HPCP. Manganese and iron were 2.5-fold higher in HPCP than CPCP. This study demonstrates that carob flour prepared in either the household or industrially is a good source of many, but not all essential nutrients, and that commercial processing of carob fruit into flour seems to affect its content of several important nutrients.


New Zealand Journal of Crop and Horticultural Science | 2001

Effect of fruit maturation on sugar and organic acid composition in two blueberries (Vaccinium arctostaphylos and V. myrtillus) native to Turkey

Faik Ahmet Ayaz; Asim Kadioglu; E. Bertoft; C. Acar; I. Turna

Abstract Some organic acids and sugars in two blueberry species from north‐east Anatolia, Turkey, were studied. The fruits of the blueberry species (Vaccinium arctostaphylos L. and V. myrtillus L.) were collected at three stages of maturity (immature, mid ripe, and ripe), and the organic acids and sugars were studied by gas liquid chromatography (GLC) and verified by gas liquid chromatography‐mass spectrometry (GLC‐MS). The soluble sugars fructose, glucose, and sucrose, and the sugar alcohol inositol were identified and quantified. Fructose and glucose represented the major sugars in the fruits. Quinic and citric acids were found to be the major organic acids in both blueberry species. The levels of these acids were significantly different (P = 0.05) at all three stages of fruit maturation. The level of malic acid increased gradually in both species, whereas the levels of citric and quinic acids decreased rapidly. The total acid level in the fruits of the two species was also significantly different. The results of this study can be used to compare the two species with other Vaccinium species.


Food Chemistry | 2016

Bog bilberry phenolics, antioxidant capacity and nutrient profile

Nesrin Colak; Hülya Torun; Jiri Gruz; Miroslav Strnad; Isidro Hermosín-Gutiérrez; Sema Hayirlioglu-Ayaz; Faik Ahmet Ayaz

Phenolics and nutrient profiles of bog bilberry (Vaccinium uliginosum L.) collected from high mountain pastures in northeast Anatolia (Turkey) were examined for the first time in this study. The major soluble sugar identified in the berry was fructose, following by glucose, and the main organic acid identified was citric acid, followed by malic acid. Eleven phenolic acids and 17 anthocyanin 3-glycosides were identified and quantified. Caffeic acid in the free and glycoside forms and syringic acid in the ester form were the major phenolic acids, and the major individual anthocyanin present in the berry was malvidin 3-glucoside (24%). The highest total phenolics and anthocyanin contents were obtained from the anthocyanin fraction in conjunction with the highest antioxidant capacity, followed by the polyphenolic and aqueous fractions, FRAP, ORAC and DPPH, in that order. Our findings can be used to compare bog bilberry with other Vaccinium berries and to help clarify the relative potential health benefits of different berries.


Journal of Emergency Medicine | 2012

Pseudocholinesterase Levels Are Not Decreased in Grayanotoxin (Mad Honey) Poisoning in Most Patients

Abdulkadir Gunduz; Asım Kalkan; Suleyman Turedi; Ismet Durmus; Suha Turkmen; Faik Ahmet Ayaz; Ahmet Ayar

BACKGROUND The symptoms of mad honey poisoning resemble those of cholinergic toxidromes; however, it is not clear whether they share a common biochemical basis. OBJECTIVES The aim of this study was to investigate a possible resemblance between mad honey poisoning and cholinergic toxidromes. METHODS This is a descriptive study performed prospectively in patients presenting to a University Medical Faculty Emergency Medicine Department emergency service with mad honey poisoning over 1 year, from September 2008 to September 2009. Adult patients with clinical findings suggesting mad honey poisoning (i.e., bradycardia, hypotension, syncope, and vertigo) and with a history of honey consumption were enrolled. Pseudocholinesterase levels in blood samples taken from the mad honey-poisoned patients were analyzed to determine whether these were lower than normal pseudocholinesterase levels for adults (5400-13,200 U/L). RESULTS The most common symptoms of the 30 patients enrolled in the study were vertigo and nausea. Low blood pressure and bradycardia were the most frequently observed physical examination findings. None of the patients enrolled had a history of disease that might cause low pseudocholinesterase. Mean pseudocholinesterase levels in our patients with mad honey poisoning were 7139.30 ± 2316.41 U/L (min-max: 1785-12,835). Blood pseudocholinesterase levels were within normal limits in 90% of patients and below normal in 10%. CONCLUSION A low pseudocholinesterase level was found in 3 (10%) of our 30 patients. These biochemical data do not support the hypothesis that mad honey poisoning should be regarded as cholinergic poisoning.


Annals of Saudi Medicine | 2015

Examination using LC-MS/MS determination of grayanotoxin levels in blood, urine, and honey consumed by patients presenting to the emergency department with mad honey intoxication and relations with clinical data: a preliminary study.

Ali Aygun; Abdulkadir Gunduz; Suleyman Turedi; Suha Turkmen; Yunus Karaca; Faik Ahmet Ayaz; Su Youn Ahn; Suncheun Kim

BACKGROUND AND OBJECTIVE Intoxications related to ”mad honey” are frequently encountered in the Black Sea region of Turkey. Intoxication is established on the basis of whether honey was consumed when history was taken at presentation. The search for a simple and reliable method for showing the grayanotoxins (GTXs) in mad honey in body fluids and in honey consumed by patients is still at the research stage. The purpose of this preliminary study was to investigate GTX levels in blood, urine, and honey consumed by patients with mad honey intoxication and to determine whether there is an association with clinical status. DESIGN AND SETTINGS This descrptive study was conducted at the department of Emergency Medicine of Karadeniz Technical University Medical Faculty in Turkey. Mad honey, blood, and urine samples were obtained from patients between September 2013 and October 2014. METHODS Four cases presenting the Department of Emergency Medicine and diagnosed with mad honey intoxication were included in the study. GTX levels in blood, urine, and honey consumed by patients were determined using liquid chromatography–tandem mass spectrometry. RESULTS Patients’ mean blood GTX I level was 30.62 ng/mL, GTX III level 4.917 ng/mL, urine GTX I level 0.447 mg/mL, and GTX III level 1.998 mg/mL. The mean GTX I level in the honey samples consumed was 4.683 mg/g and GTX III level 8.423 mg/g. CONCLUSION The present study is unique in representing the first time that GTXs have been determined in human body fluids. There is now an urgent need for a large series of studies to provide statistical evidence whether there is a relationship between levels of toxins in human body fluids and clinical picture.


Polish Journal of Food and Nutrition Sciences | 2016

Comparison of phenolics and phenolic acid profiles in conjunction with oxygen radical absorbing capacity (ORAC) in berries of Vaccinium arctostaphylos L. and V. myrtillus L.

Nesrin Colak; Hülya Torun; Jiri Gruz; Miroslav Strnad; Michaela Šubrtová; Huseyin Inceer; Faik Ahmet Ayaz

Abstract Caucasian blueberry (Vaccinium arctostaphylos L.) and bilberry (V. myrtillus L.), both native to Turkey, were evaluated for their total phenolics (TP) and anthocyanin (TAC) contents. Individual compositions of free phenolic acids and phenolic acids liberated from ester and glycoside forms were analyzed using UPLC-MS/MS. Berry extracts of each species were separated into three different fractions (sugar/acid, polyphenolic and anthocyanin) by solid phase extraction (SPE). The anthocyanin fractions of each species had the highest level of TP and TAC contents and ORAC values. Each species contained 10 phenolic acids representing each fraction, but in different quantities. The phenolic acids liberated from the esters and glycoside forms were caffeic acid and p-coumaric acid. The fractions containing phenolic acids liberated from ester and glycoside forms had a higher antioxidant capacity than that from free phenolic acids. The data suggest that both berries have potential as good dietary sources of phenolic antioxidants.

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Hülya Torun

Karadeniz Technical University

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Nesrin Colak

Karadeniz Technical University

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Robert H. Glew

University of New Mexico

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Sema Hayirlioglu-Ayaz

Karadeniz Technical University

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Ahmet Colak

Karadeniz Technical University

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Ahmet Demirbas

Karadeniz Technical University

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Neslihan Demirbas

Karadeniz Technical University

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Abdulkadir Gunduz

Karadeniz Technical University

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Mark Millson

National Institute for Occupational Safety and Health

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Carlos Sanz

Spanish National Research Council

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