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    CHIRAL STATIONARY PHASES USED FOR ENANTIOMERIC RESOLUTION
    (Bilal GÜMÜŞ, 2015) Erdoğan, Ömer; Topal, Giray
    Enantiomer separation has attracted increasing attentions in pharmaceutical industry, due to great differences in pharmacological, toxicological and/or metabolic activities of enantiomeric drugs in living system. Several methods have been succesfully used to achieve chiral separation. To date the chromatographic method is one of the most effective. Numerous kinds of CSPs have been developed for chiral separation these include cyclo-dextrins, polysaccharides, macrocyclic antibiotics, ligand-exchange, Pirkle, crown ethers and protein derivatives. İn this rewiev we will inform ligands and macromolecules used as CSP.
  • Küçük Resim
    Öğe
    Heterocyclic Schiff base derivatives containing pyrazolone moiety: Synthesis, characterization, and in vitro biological studies
    (Wiley, 2021) Çınar, Ercan; Başaran, Eyüp; Erdoğan, Ömer; Çakmak, Reşit; Boğa, Mehmet; Çevik, Özge
    In this study, some pyrazolone-based Schiff base derivatives 2a-e (except 2a)were synthesized for the first time and structurally illuminated by some spec-troscopic techniques (1H,13C NMR, FT-IR) and elemental analysis. Allsynthesized molecules were screened for their anticancer and antioxidantactivities, as well as AChE, BChE, and tyrosinase inhibitory properties.The obtained results exhibited that compounds 1b (IC50= 9.497 Μ) and 2a(IC50= 30.49 Μ) significantly decreased the proliferation of HeLa cells. Onthe other hand, the apoptotic effects of these two compounds were investigatedwith acridine orange/propidium iodide double staining. The apoptotic cellratios of the molecules treated with these two compounds were determined as60 and 64%. Compound 2b (IC50= 17.95 ± 0.47 Μ ) was determined to be avery active substance in the ABTS assay. Compound 2e (A0.5= 43.75± 0.62 M) indicated the closest antioxidant activity to the standard compoundα-TOC (A0.5= 50.58 ± 0.39 M) in the cupric reducing antioxidant capacity(CUPRAC) assay. In inhibition studies of enzymes, it was determined thatcompound 2c had a very active molecule in AChE, BChE, and tyrosinaseinhibitory activities with 82.79 ± 1.03, 91.39 ± 1.06, and 92.60 ± 1.80% inhibi-tion, respectively. It was determined that the target molecules 2a-e showedbetter antioxidant and enzyme inhibitory activities than those of ester deriva-tives 1a-e.
  • [ X ]
    Öğe
    Protein temelli yeni bir HPLC kolon dolgu maddesinin hazırlanması ve bazı rasemik bileşiklerin bu kolon üzerinden enantiyomerik rezolüsyonu
    (2015) Erdoğan, Ömer
    Bu çalışmada protein temelli(CSP-I) ve Pirkle-tip(CSP-II) iki kiral sabit faz sentezlendi. Bu CSP’lerin yapısı elementel analiz ile aydınlatılarak parçacık boyutu SEM ile ölçüldü. Hazırlanan bu CSP’ler 150x4,6 mm ebatlarındaki HPLC kolona dolduruldu. CSP-I üzerinden rasemik formdaki mandelik asit, metil mandelat, epinefrin, propranolol, ibuprofen, naproxen, treonin, α-feniletilamin ve 3-hidroksibütirik asit gibi bazı bileşiklerin rezolüsyonu 100mM pH=6, pH=7, pH=8 fosfat tamponunda 1mL/dk, 1.5mL/dk, 2mL/dk, 2.5mL/dk ve 3mL/dk akış hızlarında çalışıldı. Bu akış hızlarında enantiyomerik olarak ayrılan her bir rasemik bileşik için rezolüsyon sabiti(Rs), ayrılma faktörü(α) gibi kromatografik parametreler hesaplandı. Bu CSP’lerden CSP-I ile enantiyomerik rezolüsyon çalışmalarında daha başarılı sonuçlar elde edildi. CSP-II verileri yeterli kromatografik parametrelere uygun sonuçlarla örtüşmediğinden, CSP-II ile ayırma işlemlerinden vazgeçildi. Anahtar Kelimeler: Bovine Serum Albumin, Enantiyomerik Rezolüsyon, HPLC, Kiral Sabit Fazlar
  • Küçük Resim
    Öğe
    Schiff base derivatives of 4-aminoantipyrine as promising molecules: Synthesis, structural characterization, and biological activities
    (Pleiades journals, 2022) Çakmak, Reşit; Başaran, Eyüp; Boğa, Mehmet; Erdoğan, Ömer; Çınar, Ercan; Çevik, Özge
    Abstract: In this study, some Schiff bases derived from 4-aminoantipyrine (4-AAP) (VI–X) were synthesized, characterized by elemental analysis (C, H, N) and three spectral techniques (FT-IR, 1H, and 13C NMR), and then their antioxidant activity was investigated by employing four different methods. Subsequently, the inhibitory influences of the synthesized molecules against acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase enzymes were tested. More importantly, the cytotoxic effects of all title molecules were also evaluated on HeLa human cervical cancer and L929 mouse fibroblast cell lines. According to the results obtained, compound (VI) (IC50: 16.82 ± 0.17 μM) showed higher ABTS cation radical scavenging activity than BHA (IC50: 17.59 ± 0.10 μM). In CUPRAC assay, it was determined that the activity ordering of the bioactive molecules has been determined as VII > X > VII > α-TOC > IX > I > II > V > VI. In AChE assay, compound (I) indicated a high potent inhibition activity with 91.75 ± 1.15% better than galanthamine. In BChE assay, compound (VII) had good BChE inhibition activity (78.76 ± 1.47%) better than galanthamine. Compound (V) showed strong tyrosinase inhibition activity with 52.85 ± 0.23% value at 200 μM concentration. Compound (III) showed the best cytotoxic effect on HeLa cells with an IC50 dose of 21.47 µM. Consequently, it can be said that some of these synthesized molecules were potentially new anti-Alzheimer drug candidate molecules.
  • [ X ]
    Öğe
    THE PREPARATION OF A NEW PROTEIN BASED HPLC COLUMN PACKING MATERIAL AND ENANTIOMERIC RESOLUTION OF SOME PHARMACEUTICAL RELATED COMPOUNDS VIA THIS COLUMN
    (Bilal GÜMÜŞ, 2016) Erdoğan, Ömer; Topal, Giray; Çakmak, Reşit; Sünkür, Murat; Canpolat, Mutlu
    In this study, BSA was bounded to 3-chloropropyl functionalized silica gel via ethylenediamine and glutaric dialdehyde. The prepared CSP was packed into 150X4.6mm HPLC column according to slurry method. The enantiomeric resolution of some pharmaceutical related compounds such as rac-mandelic acid, rac-methyl mandelate, rac-epinephrine, rac-propranolol, rac-?-phenylethylamine and rac-3-hydroxybutyric acid was employed in 1mL/rpm, 1,5mL/rpm, 2mL/rpm, 2,5mL/rpm, 3mL/rpm flow rate in various pHs such pH=6, pH=7, pH=8 0,1M phosphate buffer. Chromatographic parameters such as Rs and ? were calculated for each resoluted compounds.