Person: DİNCEL, DEMET
8 results
Search Results
Now showing 1 - 8 of 8
Publication Metadata only Simultaneous Determination of Phenol and p-Cresol in Human Urine by an HPLC Method(2016-06-01) Tekkeli, S. E. Kepekci; Kiziltas, M. V.; Dincel, DEMET; ERKOC, R.; Topcu, GÜLAÇTI; TEKKELİ, ŞERİFE EVRİM; DİNCEL, DEMET; TOPÇU, GÜLAÇTIIntroduction: In patients with chronic kidney disease (CKD), uremic toxins accumulate in blood and cannot be excreted with urine. Accumulation of these toxins has negative effects on many body functions. Because of the importance of these toxins, we developed and validated a simple, sensitive, accurate, and precise method for the determination of two main uremic toxins:phenol and p-cresol in human urine. Materials and methods:Separation of these analytes in urine samples was achieved by reverse-phase high-performance liquid chromatography (RP-HPLC) with a C18 column at 35 degrees C using the mobile phase of methanol-water (65:35) at a flow rate of 1.4 mL min(-1). Fluorimetric detection was used at 284 nm for excitation and 310 nm for emission. Results:The method is linear over the range of 1.5-35 ng mL(-1) and 1-45 ng mL(-1) for phenol and p-cresol, respectively. The method was applied to urine samples from 10 healthy subjects and 10 chronic kidney disease patients. Conclusions:This assay appears to be useful in routine analysis of clinical samples for simultaneous determination of phenol and p-cresol levels in urine.Publication Metadata only LIQUID CHROMATOGRAPHIC ANALYSIS OF CAROTENOIDS IN FOODS(2019-06-01) Tekkeli, Serife Evrim Kepekci; DİNCEL, DEMET; Onal, Cem; Onal, Armagan; Sagirli, Olcay; DİNCEL, DEMET; TEKKELİ, ŞERİFE EVRİMCurrent scientific studies indicate that carotenoids (CRTDs) are beneficial for maintaining health and lowering the risk of different pathologies. Considering the increasing role of carotenoids in healthcare, determination of carotenoid content of foods become important. Mostly, the analytical procedures that are used for this aim, are based on extraction techniques followed by different analytical procedures, especially high performance liquid chromatography. In this publication, a review of various analytical techniques developed for the determination of carotenoids in different food commodities starting from 2006 up to now, has been presented.Publication Metadata only Docking Studies of Natural Product Derived Carvacrol Type Aromatic Monoterpenes Against COVID-19 and Comparison with Used Synthetic Drugs: Potential of Carvacryl Acetate Against SARS-CoV-2 (COVID-19)(2023-06-01) Özhan Kocakaya Ş.; Ertaş A.; Yener İ.; Arıca E.; Dincel D.; DİNCEL, DEMETPublication Metadata only Preparation of Helichrysum plicatum DC. subsp. plicatum Extracts by Different Extraction Methods and Quantitative Analysis of Phenolic Compounds(2022-11-25) Dincel D.; Kızılarslan Hançer Ç.; DİNCEL, DEMET; KIZILARSLAN HANÇER, ÇAĞLAPublication Metadata only Standard Water Generating Vials for Lipophilic Compounds(2023-01-17) Dincel D.; Rosales-Solano H.; Zeinali S.; Pawliszyn J.; DİNCEL, DEMETAmerican Chemical Society.The study of non-polar compounds in aqueous environments has always been challenging due to their poor solubility in aqueous media. The low affinity of non-polar compounds toward polar solutions facilitates their attachment to glassware, which results in unstable sample concentrations. To address this challenge, and to enable the preparation of a stable mixture of hydrophobic compounds in an aquatic environment, we introduce an in-vial standard water generating system consisting of a vial containing appropriate aqueous solution and a polydimethylsiloxane thin film spiked with target compounds. In this system, a solution with a stable analyte concentration is attained once equilibrium between the thin-film and aqueous solution has been achieved. The developed standard water system was studied using endocannabinoids and phospholipids as model hydrophobic compounds of biological importance, with results indicating that the concentration of hydrophobic compounds in water can remain stable over multiple days. The results also showed that analytes released from the thin film can compensate for analyte loss due to extractions with solid-phase microextraction fibers, thereby re-establishing equilibrium. Thus, the vial is suitable for the repeatable generation of non-polar standards for routine analysis and quality control. The results of this work show that the developed system is stable and reproducible and therefore appropriate for studies requiring the measurement of free concentrations and accurate quantification.Publication Metadata only A Review of Medicinal Properties of Ginkgo biloba L.(2023-05-01) Dincel D.; Aydemir G. G.; Altınbaşak O.; Büyükkılıç Altınbaşak B.; Yüksel Mayda P.; DİNCEL, DEMETThe history of the Ginkgo biloba L. species’ history dates back to very ancient times. It can live for approximately a thousand years and it is quite resistant to adverse conditions. Its leaves contain important components that make them useful for medicinal purposes. In addition, its seeds have also been used as a therapeutic agent in traditional Chinese medicine. G. biloba extracts are usually used in standardized dosage forms in medicinal preparations. Today, the preffered form is a standardized extract of G. biloba called Tebonin Egb761. Studies have shown that G. biloba leaf extract is effective in treating symptomatic relief of mild to moderate cerebral insufficiency in humans. It provides effective treatment in both Alzheimer's and vascular dementia patients. The herbal extract can also have positive effects on the quality of life in healthy individuals. G. biloba is effective against inner ear disorders and provides protection against endothelial damage. Besides, scientific studies have demonstrated that it has antioxidant, anti-inflammatory, antiviral, antibacterial, antidiabetic, anticancer, neuroprotective, cardioprotective, and many other effects. G. biloba is considered an important nutraceutical due to its scientifically proven effects. There is a growing interest in the scientific community regarding this plant. In this study, a review was made by compiling the data obtained from the literature on the "botanical characteristics", "history", "bioactive components", and "biological activities" of the G. biloba species.Publication Metadata only A New Method for Therapeutic Drug Monitoring of Anxiolytic Drugs in Plasma by LC-MS/MS(2023-07-02) Kul A.; Al S.; Özdemir M.; Dincel D.; Sağırlı A. O.; DİNCEL, DEMETPublication Metadata only Therapeutic Drug Monitoring of the Free and Total Valproic Acid in Human Plasma by LC-MS/MS(2023-07-02) Dincel D.; Kul A.; Sağırlı A. O.; DİNCEL, DEMET