Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2027Design, Synthesis, and X-ray Characterization of Benzohydrazide Derivatives as Cholinesterase Inhibitors for the Treatment of Alzheimer’s Disease: An Experimental and Computational Approach to Biological Activity
Topal, Fevzi; Ünver, Hakan; Topal, Meryem; Çevik, Ulviye Acar; Kırboğa, Kevser Kübra; Işık, Mesut; Beydemir, Şükrü
In this study, a series of new benzohydrazide derivatives (1a-i) were synthesized, and characterized as potential cholinesterase inhibitors for use in the treatment of Alzheimer’s disease (AD). The inhibitory activities of the synthesized compounds against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were evaluated using in vitro and in silico methods. IC50 values for AChE inhibition ranged from 29.50 to 46.21 nM, with compound 1c exhibiting the highest inhibitory potential at an IC50 of 29.50 nM. For the BChE enzyme, the strongest effect was observed with compound 1d at an IC50 of 55 nM. The synthesized derivatives exhibited higher inhibitory potential compared to the reference tacrine (IC50: 58.73 nM for AChE and 187.30 nM for BChE) against cholinesterase enzymes through both competitive and non-competitive inhibition mechanisms. Molecular docking (ΔG: -10.67 to -9.95 kcal/mol for AChE; -9.80 to -8.69 kcal/mol for BChE) and 100 ns molecular dynamics simulations supported the binding affinities and indicated the dynamic stability of the enzyme-inhibitor complexes, in agreement with the experimental inhibition data. In silico ADMET profiling indicated favourable drug-likeness and high predicted gastrointestinal absorption and blood-brain barrier permeability (TPSA 41.46-61.69 A2), and structural alert screening returned no PAINS matches. The findings suggest that these derivatives may serve as promising lead compounds for further investigation as potential cholinesterase inhibitors relevant to AD, pending experimental cytotoxicity evaluation.
- MakaleAçık Erişim2026Synthesis, Characterization, Biological Properties, and Sensor Applications of Novel Thiosemicarbazone Derivatives
Gezegen, Hayreddin; Özbek, Oguz; Topal, Meryem; Şahin, Hatice; Koçyiğit, Ümit M.
In this study, novel thiosemicarbazone derivative molecules (5a–j) were synthesized. The characterization of the synthesized molecules was carried out using 1H–, 13C–NMR, FT–IR, and Q–TOF spectroscopic techniques. Then, the inhibitory effect of these compounds was examined for human carbonic anhydrase I and II (hCA I, and II) and acetylcholinesterase (AChE). The hCA I II, and AChE were efficiently inhibited by synthesized thiosemicarbazone derivatives, with Ki values in the range of 0.293–1.666 µM for hCA I, 0.298–1.332 µM for hCA II, and 52.51–138.63 µM for AChE, respectively. Finally, the sensor properties of the synthesized thiosemicarbazone derivatives were investigated. The newly synthesized thiosemicarbazone derivative molecules exhibited high selectivity towards Pb2+ ions. The sensor prepared with 5a from these molecules had a Nernstian behavior of 28.8 ± 1.5 mV/decade and a low detection limit of 2.86 × 10−6 M in a wide concentration range of 1.0 × 10−1–1.0 × 10−5 M. The newly proposed sensor also had a wide pH working range (5.0–10.0), a very fast response time (5 s), and good reproducibility. The newly fabricated sensors were used as indicator electrodes for the potentiometric titration of Pb2+ ions with ethylenediaminetetraacetic acid (EDTA) and were successfully applied for the determination of Pb2+ ion content in different water samples.
- MakaleAçık Erişim2026Investigation of the enzyme-inhibitory, antibacterial, and anticancer properties of metal phthalocyanines
Topal, Meryem; Topal, Fevzi; Yilmaz, Fırat; Bulut Atalay, Esra; Koçyiğit, Ümit Muhammet; Güzel, Emre
In this study, the enzyme inhibitory, antibacterial, and anticancer activities of a phthalonitrile derivative and its metal phthalocyanines (Pcs; indium, zinc, copper, cobalt, and manganese; 1–6) were investigated. The cobalt and manganese Pcs were synthesized for the first time in this study. The inhibitory activities of the symmetric Pcs, which were expected to interact with acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) via their 4-(isopropylbenzyl)oxy substituents through host–guest interactions, were investigated. More selective inhibition of AChE than BChE was observed for these compounds. For AChE, CoPc was identified as the most potent inhibitor (IC50 = 14.81 nM), whereas for BChE, InPc was identified as the most potent inhibitor (IC50 = 56.35 nM). The Ki values indicated that most compounds exhibited competitive inhibition; copper phthalocyanine (CuPc) showed particularly strong inhibition against AChE (Ki = 3.08 nM ± 1.12), whereas the lowest Ki value against BChE was observed for MnPc (Ki = 25.98 ± 1.97 nM). Most compounds exhibited competitive inhibition; however, CuPc showed competitive inhibition toward AChE but a noncompetitive inhibition pattern toward BChE. Dual inhibition of AChE and BChE by these compounds may be promising for addressing cholinergic deficits associated with Alzheimer’s disease. In addition, the acceptability of compounds 1–6 with respect to pharmacological drug-likeness criteria was assessed based on predicted absorption, distribution, metabolism, excretion (ADME) outcomes. In antibacterial tests, varying levels of inhibition were observed against selected bacterial strains. In anticancer assays, all compounds exhibited high cytotoxicity against the MCF-7 breast cancer cell line. Higher antiproliferative activity was observed for CuPc than for the other compounds. Morphological changes were induced in cancer cells by CuPc and MnPc. Overall, these compounds may have potential as enzyme inhibitors and as antibacterial and anticancer agents.
- MakaleAçık Erişim2026Mono- and Bis-Ureido Sulfapyridines as Nanomolar Dual Cholinesterase Inhibitors: Enzyme Kinetics, Molecular Docking, and ADME/Tox Insights
Yapar, Gonul; Akocak, Suleyman; Lolak, Nebih; Topal, Meryem; Türkes, Cuneyt; Topal, Fevzi; Durgun, Mustafa; Koçyigit, Umit Muhammet; Isik, Mesut; Beydemir, Sukru
A series of mono- and bis-ureido sulfapyridine derivatives (SP-1-SP-10) were synthesized and evaluated as dual cholinesterase inhibitors targeting acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). All compounds exhibited nanomolar inhibition. The most potent AChE inhibitors were SP-8 (K-i = 5.25 +/- 0.73 nM), SP-9 (5.09 +/- 0.44 nM), and SP-10 (5.74 +/- 0.55 nM), significantly outperforming tacrine (K-i = 105.03 +/- 8.85 nM) under identical conditions. For BChE, SP-9 showed the strongest inhibition (K-i = 26.38 +/- 2.07 nM) compared with tacrine (172.03 +/- 32.42 nM). Kinetic analyses revealed competitive inhibition toward AChE for all derivatives, whereas BChE inhibition displayed both competitive and noncompetitive patterns depending on structural features. Glide XP docking using AChE (PDB: 7XN1) and BChE (PDB: 4BDS), complemented by MM-GBSA binding free energy calculations, supported favorable ligand accommodation within the catalytic pockets and highlighted the importance of aromatic and hydrophobic interactions. In silico ADME/Tox analysis revealed a potency-drug-likeness trade-off: mono-ureido derivatives complied with Lipinski's rule of five and showed high predicted oral absorption, whereas bis-ureido derivatives, despite superior enzymatic potency, exhibited multiple drug-likeness violations. These findings identify the ureido-sulfapyridine scaffold as a potent enzymatic dual cholinesterase inhibitory framework, warranting further structural optimization to improve pharmacokinetic properties.
- MakaleYalnız künye2026Novel Approach to Synthesis of Diaryl Tacrine Derivatives and Evaluation of Their Inhibitory Effects on Cholinesterase Enzymes
Topal, Fevzi; Ökten, Salih; Misir, Busra Albayrak; Koçyigit, Umit Muhammet; Derin, Yavuz; Atalay, Vildan Enisoglu; Tutar, Ahmet; Topal, Meryem
The development of effective acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitors remains a crucial objective in the treatment of neurodegenerative diseases, including Alzheimer's disease (AD). In this study, a novel synthetic approach was established to prepare a series of diaryl-substituted tacrine derivatives. Initially, brominated aminobenzonitrile was subjected to Suzuki-Miyaura cross-coupling reactions with various aryl boronic acids to yielding diaryl-substituted aminobenzonitriles at yields of 60%-72%. These intermediates were then cyclized with cyclohexanone and cycloheptanone under Friedl & auml;nder conditions using BF3 & centerdot;OEt2 as a catalyst, affording six- and seven-membered diaryl tacrine analogues in yields of 52%-68%. All synthesized compounds were characterized by NMR, IR, and elemental analysis. The inhibitory activities of these compounds (7-16) against AChE and BChE were evaluated, and several analogs demonstrated potent dual-enzyme inhibition at nanomolar concentrations. Notably, compounds 8 and 13 exhibited half maximal inhibitory concentration (IC50) values of 6.848 and 8.545 nmol/L for BChE, respectively, indicating strong potential as selective cholinesterase inhibitors. The structure-activity relationship (SAR) analysis revealed the influence of aryl substituents on the potency and selectivity of enzyme inhibition. Compared to previously reported tacrine derivatives, the newly synthesized analogs exhibited superior inhibitory profiles, indicating their potential as lead compounds for further development in AD therapeutics. [GRAPHICS] .
- MakaleAçık Erişim2025Exploring the Antioxidant and Neuroprotective Potential of Muscari armeniacum: Phenolic Profiling and Enzyme Inhibition
Topal, Fevzi; Menevseoglu, Ahmed; Topal, Meryem; Yilmaz, Firat
This study aimed to investigate the antioxidant and enzyme inhibitory properties of Muscari armeniacum, a plant native to Türkiye, which is known for its bioactive compound content. Ethanol extracts of Muscari armeniacum were prepared and analyzed using a variety of bioanalytical methods to assess its potential health-promoting properties. The antioxidant capacity was evaluated through Fe³⁺-Fe²⁺ reduction capacity, CUPRAC, DPPH, and ABTS radical scavenging activities. Additionally, the total phenolic and flavonoid contents of the extracts were determined, as these compounds are critical indicators of antioxidant potential. The antioxidant activity of Muscari armeniacum was compared with five standard antioxidants commonly used for benchmarking: BHA, α-tocopherol, BHT, trolox, and ascorbic acid. The extract demonstrated a high flavonoid content (23.24 µg QE/mg extract) and a significant amount of phenolics (14.38 µg GAE/mg extract), with the flavonoid content being particularly noteworthy. In addition to its antioxidant properties, the enzymatic activity assays revealed that the extract significantly inhibited acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes, which are associated with neurodegenerative diseases such as Alzheimer’s. The IC₅₀ values were determined to be 54.14 mg/mL (R² = 0.9695) for AChE and 58.73 mg/mL (R² = 0.9609) for BChE, indicating moderate enzyme inhibition. These results suggest that Muscari armeniacum could serve as a valuable source of bioactive compounds with significant antioxidant and enzyme inhibitory activities. Its potential applications in the treatment of oxidative stress-related diseases and neurodegenerative disorders make it a promising candidate for further pharmacological studies. This research underscores the importance of exploring native plants for their medicinal and therapeutic potential, contributing to the development of alternative treatments for challenging health conditions.
- MakaleAçık Erişim2025Comprehensive Analysis of the Antioxidant and Enzyme Inhibitory Properties and Phenolic Compounds of Phlomis armeniaca: Potential Applicant in Neurodegenerative Diseases
Menevseoglu, Ahmed; Yılmaz, Fırat; Topal, Meryem; Topal, Fevzi
This study investigates the antioxidant and enzyme inhibitory properties of Phlomis armeniaca, a perennial plant native to the eastern and southeastern regions of Turkey. Ethanol extracts of the plant were analyzed using various bioanalytical methods, including Fe3⁺-Fe2⁺ reducing power, Cupric Reducing Antioxidant Capacity, 1,1-diphenyl-2-picryl-hydrazyl (DPPH), and 2,2-azinobis 3-ethylbenzthiazoline-6-sulfonic acid (ABTS) radical scavenging activities, as well as total phenolic and flavonoid content assessments. The results showed that P. armeniaca is rich in phenolic (38.75 ± 0.59 µg gallic acid equivalents/mg extract) and flavonoid compounds (39.34 ± 4.08 µg quercetin equivalents/mg extract). The plant demonstrated significant inhibitory effects on acetylcholinesterase (half-maximal inhibitory concentration [IC50]: 45.00 ± 0.48 mg/mL) and butyrylcholinesterase (IC50: 84.51 ± 0.84 mg/mL) enzymes, indicating its potential use in treating neurodegenerative diseases such as Alzheimer's. The study also highlighted P. armeniaca’s high chlorogenic acid, salicylic acid, 4-dihydroxybenzoic acid, and quinic acid contents, supporting its antioxidant capacity. These findings suggest that P. armeniaca could be a valuable natural resource for developing therapeutic agents to manage oxidative stress and related conditions, warranting further pharmacological exploration.
- MakaleAçık Erişim2025Sulfonamide-Bearing Pyrazolone Derivatives as Multitarget Therapeutic Agents: Design, Synthesis, Characterization, Biological Evaluation, In Silico ADME/T Profiling and Molecular Docking Study
Lolak, Nebih; Akocak, Suleyman; Topal, Meryem; Koçyigit, Umit Muhammet; Isik, Mesut; Türkes, Cuneyt; Topal, Fevzi; Durgun, Mustafa; Beydemir, Sukru
The research and design of new inhibitors for the treatment of diseases such as Alzheimer's disease and glaucoma through inhibition of cholinesterases (ChEs; acetylcholinesterase, AChE and butyrylcholinesterase, BChE) and carbonic anhydrase enzymes are among the important targets. Here, a series of novel sulfonamide-bearing pyrazolone derivatives (1a-f and 2a-f) were successfully synthesized and characterized by using spectroscopic and analytical methods. The inhibitory activities of these newly synthesized compounds were evaluated both in vitro and in silico for their effect on carbonic anhydrases (hCA I and hCA II isoenzymes) and ChEs. The in vitro studies showed that these novel compounds demonstrated potential inhibitory activity, with K-I values covering the following ranges: 18.03 +/- 2.86-75.54 +/- 4.91 nM for hCA I, 24.84 +/- 1.57-85.42 +/- 6.60 nM for hCA II, 7.45 +/- 0.98-16.04 +/- 1.60 nM for AChE, and 34.78 +/- 5.88-135.70 +/- 17.39 nM for BChE. Additionally, many of these compounds showed promising inhibitory activity, and some showed higher potency than reference compounds. While the in silico studies have also identified the potential binding positions of these compounds, using the crystal structures of hCA I, II, AChE and BChE receptors. The varying affinities demonstrated by these designed compounds for ChEs and hCA isoenzymes show that these compounds could hold promise as potential alternative agents for selectively inhibiting ChEs and hCAs in the treatment of diseases such as Alzheimer's disease and glaucoma.
- MakaleAçık Erişim2024Exploring the Impacts of Angelica purpurascens Extracts on Anticholinergic, Antidiabetic, Antibacterial Potential, and Antioxidant Capacity
Topal, Meryem; Topal, Fevzi; Yilmaz, Fırat
In Kars-Sarıkamış-Soğanlı, Angelica purpurascens (A. purpurascens) emerges as a promising natural antioxidant source. Extracts from its leaves, branches, and flowers underwent thorough bioanalytical assessments. The leaf extract exhibited the highest concentrations of herbal flavonoids (45.22 µg QE/mg extract) and total phenolics (28.96 µg GAE/mg extract). Branch extracts demonstrated significant enzymatic activity against AChE and BChE with IC50 values of 37.26 mg/mL and 9.08 mg/mL respectively. The flower extract displayed notable antibacterial properties. This study sheds light on the therapeutic potential of A. purpurascens ethanol extracts, suggesting benefits for Alzheimer’s, cell damage-induced diseases, and diabetes mellitus. It pioneers new enzymatic and antioxidant insights and contributes to understanding this abundant Türkiye species. A. purpurascens holds promise for pharmaceutical exploration, offering potential solutions for challenging health conditions.
- MakaleYayıncıda açık erişim2024Novel asymmetric biscarbothioamides as Alzheimer's disease associated cholinesterase inhibitors: synthesis, biological activity, and molecular docking studies
Muglu, Halit; Yakan, Hasan; Erdogan, Musa; Topal, Fevzi; Topal, Meryem; Turkes, Cuneyt; Beydemir, Sukru
Exploring novel frameworks for treating Alzheimer's disease is an ambitious objective. In this particular context, a range of asymmetric biscarbothioamide derivatives (3a-l) with varying substitutions have been meticulously designed and effectively synthesized. The newly synthesized compounds have all been definitively characterized using established spectroscopic techniques such as 1H-NMR, 13C-NMR, FT-IR, and elemental analysis. In vitro, all the derivatives (3a-l) were evaluated to assess their inhibitory potential against cholinesterase enzymes (acetylcholinesterase, AChE, and butyrylcholinesterase, BChE). The outcomes demonstrated that these derivatives were potent and exhibited selectivity in inhibiting AChE, except for compounds 3b and 3e, which specifically inhibited BChE, showcasing varying degrees of KI values. Significantly, compounds 3j (KIs of 11.91 +/- 2.25 nM for AChE and 77.76 +/- 8.02 nM for BChE) and 3h (KIs of 14.73 +/- 2.30 nM for AChE and 59.54 +/- 6.20 nM for BChE) emerged as the most potent dual inhibitors of AChE and BChE within the series, respectively, with KI constants even lower than those of the standard drug tacrine (KIs of 68.70 +/- 5.39 nM for AChE and 111.60 +/- 10.52 nM for BChE). Furthermore, their potential scavenging activity against DPPH and ABTS radicals was evaluated. To further validate the experimental findings, molecular docking studies were performed in silico to ascertain the binding modes of these compounds with the active pockets of AChE and BChE enzymes. Investigating innovative frameworks for addressing Alzheimer's disease is a challenging goal. In this specific scenario, a selection of asymmetric biscarbothioamide derivatives (3a-l) with different substitutions has been carefully formulated and successfully synthesized.
- MakaleYalnız künye2023Determination of the Antioxidant Capacity of Puerarin and Its Effect on Cholinesterases by in vitro and in silico Methods
İnan Ergün, Aslı; Topal, Meryem
Puerarin, which was used as a natural isoflavone in this study, was obtained from the Kudzu plant. The inhibitory effect of puerarin on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes was investigated. The IC50 values of AChE (177.73 nM) and BChE (315.07 nM) were determined. The binding mechanism of puerarin, which has a high inhibitory effect on the active site of the enzyme, was demonstrated by the molecular docking method. The antioxidant activity was evaluated for the same molecule. For this purpose, Fe3+-Fe2+ reducing capacity, ABTS radical scavenging activity, CUPRAC method, DPPH⋅ scavenging activity and DMPD radical scavenging method were used. The percentage (%) inhibition amount of puerarin molecule was calculated as 99.33 % for ABTS radical scavenging activity, which is the more preferred method for natural products. The absorbtion value of iron reduction of Puerarin was 0.122±0.010, and the value of copper reduction was 0.633±0.026. Our research efforts include uncovering the potent antioxidant potential of puerarin and, simultaneously, a comparative study of tacrine, primarily emphasizing its inhibitory effects against AChE and BChE enzymes. The puerarin is expected to be a guide for drug discovery against many problems, especially oxidative cell damage in Alzheimer's disease, mitochondrial dysfunction (MD), cancer, and cardiovascular diseases.
- MakaleYalnız künye2023LC-HRMS Profiling and Phenolic Content, Cholinesterase, and Antioxidant Activities of Terminalia citrina
Özler, Ebubekir; Topal, Fevzi; Topal, Meryem; Öztürk Sarıkaya, Sevim Beyza
Terminalia citrina (T. citrina) belongs to the Combretaceae family and is included in the class of medicinal plants in tropical countries such as Bangladesh, Myanmar, and India. The antioxidant activities of lyophilized water (WTE) and alcohol extracts (ETE) of T. citrina fruits, their phenolic content by LC-HRMS, and their effects on cholinesterases (ChEs; AChE, acetylcholinesterase, and BChE, butyrylcholinesterase) were investigated. Especially ten different analytical methods were applied to determine the antioxidant capacity. Compared with similar studies for natural products in the literature, it was determined that both WTE and ETE exhibited strong antioxidant capacity. Syringe and ellagic acids were higher than other acids in ETE and WTE. IC50 values for ETE and WTE in DPPH radical and ABTS⋅+ scavenging activities were calculated as 1.69–1.68 μg mL−1 and 6.79–5.78 μg mL−1, respectively. The results of the biological investigations showed that ETE and WTE had an inhibition effect against ChEs, with IC50 values of 94.87 and 130.90 mg mL−1 for AChE and 262.55 and 279.70 mg mL−1 for BChE, respectively. These findings indicate that with the prominence of herbal treatments, T. citrina plant may guide the literature in treating Alzheimer's Disease, preventing oxidative damage, and mitochondrial dysfunction.
- MakaleAçık Erişim2022Evaluation of the in vitro antioxidant, antidiabetic and anticholinergic properties of rosmarinic acid from rosemary (Rosmarinus officinalis L.)
Topal, Meryem; Gulcin, İlhami
In this study, antidiabetic, anticholinergic, and antioxidant abilities of rosmarinic acid were evaluated and compared to standards. To determine its antioxidant activity different in vitro bioanalytical methods, including total antioxidant activity (TAA), ABTS•+ scavenging activity, O2•- scavenging activity, DPPH· scavenging activity, DMPD•+ scavenging activity, potassium ferric cyanide reduction ability, cupric ion (Cu2+) reduction capacity, H2O2 scavenging activity, and ferrous ions (Fe2+) binding activities were separately performed. Also, butylated hydroxyanisole (BHA), Trolox, α-tocopherol, and butylated hydroxytoluene (BHT) were used as the reference antioxidants. Rosmarinic acid inhibited the linoleic acid emulsion peroxidation by 89.2% while BHA, BHT, Trolox and α-tocopherol inhibited as 87.3, 97.6, 90.3 and 75.3%, respectively, at the same concentration (30 μg/mL). When these results are evaluated, rosmarinic acid had effective TAA than BHA and α-tocopherol and close to BHT and Trolox. In addition, rosmarinic acid exhibited Kİ values of 9.67 ± 0.81 nM towards acetylcholinesterase (AChE) and 33.56 ± 2.96 nM against α-glycosidase enzymes.
- MakaleYalnız künye2021Determination of Angelica archangelica’s Antioxidant Capacity and Mineral Content
Topal, Meryem; Ozturk Sarıkaya, S. Beyza; Topal, Fevzi
The aim of this study was to determine the mineral contents by ICP-MS and the antioxidant capacity of Angelica archangelica plant, which is not well known in the literature. For this purpose, ethyl alcohol extracts of the branches and leaves of the plant; different bioanalytical methods such as reducing capacity by Fe3+−Fe2+ transformation method, Fe3+-TPTZ reducing capacity by FRAP method, Cu2+-Cu+ reducing capacity by CUPRAC method, the ferric ions (Fe2+) chelating activity by using bipyridyl reagent, DPPH (1,1-diphenyl-2-picryl-hydrazyl) free radical, DMPD (N,N-dimethyl-p-phenylenediamine), ABTS (2,2’-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) radical scavenging activities, total antioxidant activity determination according to thiocyanate method, total phenolic and total flavonoid activity were used. As standard, BHT, BHA, α-Tocopherol, Trolox were used. A. archangelica branches and leaves demonstrated 88.13 % and 93.90 % inhibition of linoleic acid emulsion peroxidation at 20 mg mL−1 concentration. Also, it was determined that both leaves and branches of A. archangelica plant were dense with P, Mg, Ca and K minerals with ICP-MS device. It is considered that the results of the manuscript will guide the antioxidant studies, medicine, cosmetics, pharmacology and food sector.
- MakaleAçık Erişim2021Antidiabetic, anticholinergic and antioxidant activities of aerial parts of shaggy bindweed (Convulvulus betonicifolia Miller subsp.) - profiling of phenolic compounds by LC-HRMS
Bingol, Zeynebe; Kiziltas, Hatice; Gören, Ahmet C.; Kose, Leyla Polat; Topal, Meryem; Durmaz, Lokman; Alwasel, Saleh H.; Gulcin, Ilhami
In order to evaluate the antioxidant activity of evaporated ethanolic extract (EESB) and lyophilized water extract (WESB) of Shaggy bindweed (Convulvulus betonicifolia Mill. Subs), some putative antioxidant methods such as DPPH. scavenging activity, ABTS(center dot)(-) scavenging effect, ferric ions (Fe3+) reduction method, cupric ions (Cu2+) reducing capacity, and ferrous ions (Fe2+) binding activities were separately performed. Also, ascorbic acid, alpha-tocopherol and BHT were used as the standard compounds. Additionally, some phenolic compounds that responsible for antioxidant abilities of EESB and WESB were screened by liquid chromatography-high resolution mass spectrometry (LC-HRMS). At the same concentration, EESB and WESB demonstrated effective antioxidant abilities when compared to standards. In addition, EESB demonstrated IC50 values of 1.946 mu g/mL against acetylcholinesterase (AChE), 0.815 mu g/mL against alpha-glycosidase and 0.675 mu g/mL against alpha-amylase enzymes.
- MakaleAçık Erişim2019Secondary metabolites of ethanol extracts of pinus sylvestris cones from eastern anatolia and their antioxidant, cholinesterase and α-glucosidase activities
Topal, Meryem
Scots pine (Pinus sylvestris) is the most widely distributed tree species among pine species. Antiradical, antioxidant properties and inhibition properties on butyrylcholinesterase (BChE), acetylcholinesterase (AChE) and α-glycosidase activities of ethanol extracts of P. sylvestris were reported from Sarikamis (Kars), Gumushane and Erzurum provinces of Turkey. The cones of P. Sylvestris from Gumushane showed the highest IC50 values in both DPPH. (14.75 µg/mL) and ABTS.+ (12.56 µg/mL) radical scavenging activities. An LC-HRMS method developed and the secondary metabolite composition of extracts were identified. The major compounds are determined as (+)-trans taxifolin, quercitrin, fumaric acid, (-) epicatechin, and nepetin-7-O-glucoside, apigenin-7-O-glucoside in P. sylvestris cones.
- MakaleAçık Erişim2019The inhibition profile of sesamol against α-glycosidase and acetylcholinesterase enzymes
Topal, Meryem
Sesamol (1,3-benzodioxol-5-ol) is found in the oilseed product, sesame. In our study, the inhibitory effects of sesamol compound on acetylcholinesterase and α-glycosidase enzymes were evaluated. Another aim of this study was to compare the inhibitory effects of sesamol to acarbose for α-glycosidase enzyme and tacrine for acetylcholinesterase (AChE). Sesamol exhibited non-competitive inhibition for both metabolic enzymes. IC50 values for AChE and α-glycosidase enzymes were calculated as 86.63 nM and 99.00 nM, respectively. On the other hand, Ki values were calculated as 46.68 nM and 75.33 nM for AChE and α-glycosidase enzymes, respectively. According to the obtained results showed effective inhibition at low concentrations.
- MakaleAçık Erişim2019Anticholinergic, antidiabetic and antioxidant activities of cinnamon (cinnamomum verum) bark extracts: polyphenol contents analysis by LC-MS/MS
Gulcin, Ilhami; Kaya, Ruya; Goren, Ahmet C.; Akincioglu, Hulya; Topal, Meryem; Bingol, Zeynebe; Cakmak, Kader Cetin; Sarikaya, Sevim B. Ozturk; Durmaz, Lokman; Alwasel, Saleh
Ethanolic (EEC) and aqueous (WEC) extracts of cinnamon (Cinnamomum verum) were evaluated for their antioxidant profiles by eight distinguished bioanalytical antioxidant methods. Their inhibitory effects were tested against some enzymes including acetylcholinesterase, butyrylcholinesterase, alpha-glycosidase and alpha-amylase, which linked to different diseases. Additionally, the antioxidant properties were determined and polyphenolic compositions of the both extracts were evaluated by LC-MS/MS analysis. According to the LC-MS/MS experiments, thirteen compounds were found in WEC and EEC. Also, p-hydroxybenzoic acid (321.1 mg/kg extract), p-coumaric acid (291.4 mg/kg extract), and pyrogallol (142.4 mg/kg extract) were found to be the most abundant ingredients in the WEC. On the other hand, pyrogallol (264.3 mg/kg extract), ferulic acid (224.7 mg/kg extract) and p-coumaric acid (170.2 mg/kg extract) were found as the most plentiful chemicals in the EEC. For the estimation of the antioxidant capacities of the both extracts (WEC and EEC), DPPH center dot and ABTS(center dot+) scavenging activities, as well as Fe3+-Fe2+, and Cu2+-Cu+ reducing assays were studied. The IC50 values of the WEC and EEC indicated that they were potent effective DPPH center dot (21. 25 and 15.71 mu g/mL) and ABTS(center dot+) (6.52 and 5.79 mu g/mL) scavengers, as well as AChE (221.33 and 110.26 mu g/mL), BChE (461.69 and 94.93 mu g/mL), alpha-glycosidase (206.86 and 220.00 mu g/mL) and alpha-amylase (189.86 and 200.86 mu g/mL) inhibitors. As a conclusion, both EEC and WEC had rich phenolic contents and demonstrated effective anticholinergic, antidiabetic and antioxidant effects.
- MakaleAçık Erişim2018Picea orientalis kozalağının antioksidan ve antiradikal özelliklerinin belirlenmesi
Topal, Meryem
Metabolizmada oluşan reaktif oksijen türleri engellenmediği sürece, DNA, protein, karbohidrat ve lipitlerde yapısal bozulmalar meydana getirir. Buna bağlı olarak hücre membranının hem stabilizesi ve hem de fonksiyonları bozulur ve birçok dejeneratif hastalıklar meydana gelir. Önceki çağlarda insanlar sağlık sorunlarını çözmek için de bitkisel tedavilere başvurmuştur. Günümüzde özellikle bilimsel olarak çalışmalar artmış özellikle alternatif tıp olarak da yaygınlık göstermiştir. Fenolik bileşik içeren bitkiler doğal antioksidan olarak genellikle kullanılmaktadır. Bu bileşikler serbest radikallerin yol açtığı reaksiyonları durdurarak veya engelleyerek kalp, kanser, ve akciğer hastalıkları gibi hastalıkların oluşumuna engellerler. Antioksidanlar, biyomoleküllerin oksidasyonunu engelleyen veya tamamen durduran maddeler olarak bilinir ve oldukça yaygın bir kullanım alanına sahiptirler. Doğu ladin, çamgiller familyasında bulunan bilimsel adı P. orientalis’dir. Yapılan bu çalışmada doğu ladin kozalağının etanol ekstreleri kullanılarak antioksidan kapasitesinin belirlenmesi hedeflenmiştir. Bu amaçla demir indirgeme kapasiteleri ve bakır indirgeme kapasiteleri, ABTS radikal giderme aktiviteleri ve DPPH radikal giderme aktiviteleri, total fenolik bileşik miktarlarını ve flavonoit bileşik miktarlarını belirleme gibi in vitro şartlarda farklı biyoanalitik metotlar ile antioksidan ve antiradikal özellikleri belirlendi. P. orientalis kozalağının DPPH radikal giderme aktivitesi için IC 50 değeri 24,75 μg mL -1 , ABTS radikal giderme aktivitesi için ise 13,42 μg mL -1 olarak tespit edildi. Buna göre yapılan metotlarda yüksek antioksidan kapasitesine sahip olduğu belirlendi.
- MakaleAçık Erişim2017Synthesis of some natural sulphonamide derivatives as carbonic anhydrase inhibitors
Gokcen, Taner; Al, Melike; Topal, Meryem; Gulcin, Ilhami; Ozturk, Turan; Goren, Ahmet C.
Carbonic anhydrase inhibitor; sulphonamides; p-hydroxybenzoic acid; 3,4,5-trihydroxybenzoic acid (gallic acid).Carbonic anhydrase inhibitors are both in clinical use as antiglaucoma, diuretics, antiepileptics and management of altitude sickness, and under investigation as anticancer, anticonvulsant and antiobesity agents. Sulphonamides have been known for decades as carbonic anhydrase inhibitors and are in clinical use. Sulphonamide derivatives of p-hydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid (gallic acid) were synthesized and their inhibition values over hCA I and hCA II isozymes, purified from human erythrocyte cells by Sepharose-4B-L-tyrosine-sulphanilamide, were determined. Compounds synthesized showed efficient carbonic anhydrase inhibition activity at low nM levels.