Person: AYAZ SEYHAN, SERAP
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AYAZ SEYHAN
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SERAP
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Publication Open Access Preparation and characterization of pure natural hydroxyapatite derived from seashells for controlled drug delivery(2022-09-01) OKTAR, FAİK NÜZHET; GÜNDÜZ, OĞUZHAN; BİLĞİÇ ALKAYA, DİLEK; AYAZ SEYHAN, SERAP; CESUR, SÜMEYYE; AYAZ SEYHAN S., Alkaya D., Cesur S., OKTAR F. N., GÜNDÜZ O.The marine species are specially used for the fabrication of bioceramic nano-powders with natural methods for their use in controlled drug delivery. However, there are only very limited studies regarding the production and synthesis of hydroxyapatite (HA)-based drug delivery systems from marine structures. In this study, poly (vinyl alcohol) (PVA) containing Rifampicin (RIF)-loaded Orange Spiny Oyster Seashell (Spondylus barbatus) hydroxyapatite (HA) composite is synthesized by an in situ ultrasound-assisted method. All samples were analyzed by X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, and Scanning electron microscope (SEM), respectively. The in vitro drug release tests of the obtained samples were performed in a phosphate-buffered medium (PBS) at 37 degrees C. Drug release was evaluated according to five varying kinetic models. In vitro RIF release from HA/PVA composite in phosphate buffer (pH 7.4) showed prolonged sustained drug release. From the drug release kinetic models, Higuchi and Korsmeyer-Peppas were found to be the best model for the three ratios based on the correlation coefficient. The diffusion component is less than 0.5, which indicates quasi-fickian diffusion. From the kinetic study results, the RIF-loaded marine phase composite has potential use in drug delivery applications as it shows positive sustained drug release behavior.Publication Open Access The extraction and determination of ellagic acid and resveratrol in blueberry species by HPLC-DAD and LCMS/MS(2023-01-01) AYAZ SEYHAN, SERAP; Seyhan S., Yalcin G., AYAZ SEYHAN S.© 2023 Marmara University Press.Ellagic acid (EA) and resveratrol (RES) are phenolic compounds naturally found in fruits. However, a significant amount of RES and EA is present in berries and their effective isolation enables the production of functional foods. In this study, EA and RES found in four highbush (Vaccinium corymbosum) blueberry varieties (Bluecrop, Brigitta, Darrow and Bluejay) were analyzed simultaneously for the first time. A chromatographic method was developed for EA and RES by HPLC-DAD and LC-MS/MS. Furthermore, pressurized liquid extraction (PLE) method was performed for the extraction of EA and RES from blueberry samples. LOD (limit of detection) and LOQ (limit of quantification) were determined as 0.1898x10-6 mol.L-1 and 0.5694x10-6 mol.L-1 for RES, 0.1271x10-6 mol.L-1 and 0.3814x10-6 mol.L-1 for EA, respectively. All the results were reevaluated according to 91.85% and 84.97% recovery value, for EA and RES, respectively. The amount of EA and RES were found out in the range of 1.65-9.16 mg/kg and 2.95-9.31 mg/kg in the lyophilized blueberry varieties.Publication Open Access Temperature dependence studies and microscopic protonation constants of L-alanine and β-alanine in acetonitrile – water mixtures(2022-07-01) BİLĞİÇ ALKAYA, DİLEK; AYAZ SEYHAN, SERAP; ERENSOY H., BİLĞİÇ ALKAYA D., AYAZ SEYHAN S.L-alanine and β-alanine are important biological molecules and have zwitterion structure. In this study, Lalanine and β-alanine’s microscopic protonation constants and thermodynamic parameters (enthalpy, entropy, and free energy changes) for the proton–ligand systems of L-alanine methyl ester, β-alanine and β-alanine methyl ester have been determined at 5; 20; 35 °C, in ACN-water (25% ACN and 50% ACN (v/v)) mixtures at constant ionic strength of 0.1000 mol L–1 NaClO4 by potentiometric method. The results shown that, L-alanine and β-alanine’s microscopic protonation constants generally tend to decrease with temperature rise and their protonation reactions in ACN-water mixtures generally favor enthalpy-driven.Publication Open Access Production, characterization, and antioxidant activity evaluation of Rheum Ribes L. extract-loaded PLA/PEG nanofibers(2023-01-01) AYAZ SEYHAN, SERAP; BİLĞİÇ ALKAYA, DİLEK; AYAZ SEYHAN S., Demirel A. B., Cesur S., BİLĞİÇ ALKAYA D.© 2023 Marmara University Press.The use of natural compounds such as biocompatible and non-toxic plant extracts, without undesired side effects, in tissue engineering applications, is highly preferred compared to chemical drugs. In recent years, many studies have been carried out to produce nanofibrous materials produced by electrospinning of bioactive plant extracts. Electrospun nanofibers have very large surface area, controllable pore size, and tunable drug release profiles. Several biocompatible polymers with excellent biocompatibility and biodegradability including poly ethylene glycol (PEG) and poly-lactic acid (PLA) have been widely used for the synthesis of nanofibers using the electrospun technique. The ethanol-water extract of the root parts of the Rheum ribes L. plant has antioxidant, antimicrobial, and antiurease effects. In this study, the characterization and performance of electrospun Rheum ribes L.-loaded (20 mg, 40 mg, and 60 mg in 20mL) poly (lactic acid) (PLA) (8%, w/v) /Polyethylene glycol (PEG) (1%, w/v) /Tween 80 (3%, w/v) nanofibrous mats for skin tissue engineering were investigated. Morphological (SEM), molecular interaction (FT-IR), thermal analysis (DSC), antioxidant activity and physical analysis were carried out after the production process. According to the results obtained, Rheum ribes L.-loaded PLA/PEG nanofibers have smooth fiber morphology in fine structure without beads, proper tensile strength and antioxidant activity. Consequently, Rheum ribes L.-loaded nanofibrous mats are suitable for skin tissue engineering applications.Publication Open Access The influence of extraction method on antioxidant potential of Tilia argentea flowers and bracts(OVIDIUS UNIV PRESS, 2020-01-01) ÇIKLA YILMAZ, DENİZ; Seyhan, Serap Ayaz; Yilmaz, Zumrut; Yilmaz, Deniz CiklaThe objective of this work was to compare the extraction of phenolic compounds from Tilia argentea flowers and bracts by using conventional (solvent extraction) and novel (ultrasound assisted) extraction methods. Ethanol (70 %) extracts were analyzed for their antioxidant activities. Total phenolic content was determined using Folin-Ciocalteu method and the antioxidant potential was determined by DPPH radical scavenging and Ferric Reducing Antioxidant Power (FRAP) assays. To determine the effect of ultrasound treatment on the extraction, same extraction parameters were applied in both methods. The results showed that extracts obtained by ultrasound assisted extraction have higher total phenolic content and antioxidant activity.