Yazar "Ozturk, Mehmet" seçeneğine göre listele

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    Anticholinesterase and Antioxidant Activities of Natural Abietane Diterpenoids with Molecular Docking Studies
    (Bentham Science Publ Ltd, 2020) Topcu, Gulacti; Akdemir, Atilla; Kolak, Ufuk; Ozturk, Mehmet; Boga, Mehmet; Bahadori, Fatemeh; Cakmar, Seda Damla Hatipoglu
    Background: Alzheimer's Disease (AD) is one of the most prevalent causes of dementia in the world, and no drugs available that can provide a complete cure. Cholinergic neurons of the cerebral cortex of AD patients are lost due to increased activity of cholinesterase enzymes. Objective: Acetylcholinesterase (AChE) and Butyrylcholinesterase (BuChE) are the two major classes of cholinesterases in the mammalian brain. The involvement of oxidative stress in the progression of AD is known. Thus, the objective of this study is to determine strong ChE inhibitors with anti-oxidant activity. Methods: In this study, 41 abietane diterpenoids have been assayed for antioxidant and anticholinesterase (both for AChE and BuChE) properties in vitro, which were previously isolated from Salvia species, and structurally determined by spectroscopic methods, particularly intensive 1D- and 2D-NMR and mass experiments. Molecular modeling studies were performed to rationalize the in vitro ChE inhibitory activity of several abietane diterpenoids compared with galantamine. Results: Thirteen out of the tested 41 abietane diterpenoids exhibited at least 50% inhibition on either AChE or BuChE. The strongest inhibitory activity was obtained for Bractealine against BuChE (3.43 mu M) and AChE (33.21 mu M) while the most selective ligand was found to be Hypargenin E against BuChE enzyme (6.93 mu M). A full correlation was not found between anticholinesterase and antioxidant activities. The results obtained from molecular modelling studies of Hypargenin E and Bractealine on AChE and BuChE were found to be in accordance with the in vitro anti-cholinesterase activity tests. Conclusion: Abietane diterpenoids are promising molecules for the treatment of mild-moderate AD.
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    Antioxidant and Anticholinesterase Activities of Some Dialkylamino Substituted 3-Hydroxyflavone Derivatives
    (Bentham Science Publ Ltd, 2017) Culhaoglu, Burcu; Capan, Asli; Boga, Mehmet; Ozturk, Mehmet; Ozturk, Turan; Topcu, Gulacti
    Background: Flavones, are a class of naturally occuring polyphenolic compounds which have 2-phenylchromen-4-one structure. Various studies showed that flavones have several pharmacological activities such as antioxidant, anti-inflammatory, antimicrobial, cytotoxic, antitumour and antiallergic. In the present study, 3-hydroxyflavones also called flavonols, posessing 4'-dialkylamino moiety were synthesized, and their antioxidant and anticholinesterase activities were investigated by comparison with unmodified 3-hydroxflavone. Method: For investigation of antioxidant potential, radical scavenging assays (DPPH., ABTS(+)-, O-2(-)) were used along with CUPRAC and lipid peroxidation inhibitory assays, as well as anticholinesterase activity by Ellman method. Results: The best results were obtained for 4'-N, N-dimethyl flavonol (1) in both antioxidant and anticholinesterase activity tests, possibly due to its least steric hinderance effect. It exhibited remarkable DPPH free radical scavenging activity (2.43 perpendicular to 0,09 mu g/mL) competing with a standard compound quercetin (2.10 +/- 0,10 mu g/mL). Moreover, the other tested flavonols also showed high antioxidant activities. Compounds 5 and 6 exhibited close IC50 values to those of compound 1. Conclusion: Antioxidant activity test results were found to be well correlated with anticholinesterase activity test results indicating possible role of antioxidant compounds in the treatment of Alzheimer's disease.
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    A detailed study on chemical and biological profile of nine Euphorbia species from Turkey with chemometric approach: Remarkable cytotoxicity of E-fistulasa and promising tannic acid content of E-eriophora
    (Elsevier Science Bv, 2018) Yener, Ismail; Olmez, Ozge Tokul; Ertas, Abdulselam; Yilmaz, Mustafa Abdullah; Firat, Mehmet; Kandemir, Sevgi Irtegun; Ozturk, Mehmet
    The propose of this study is to investigate the chemical constituents of nine Euphorbia species; namely, E. aleppica, E. eriophora, E. macroclada, E. grisophylla, E. seguieriana subsp. seguieriana, E. craspedia, E. denticulata, E. falcata and E. fistulosa by LC-MS/MS as well as their antioxidant, anticholinesterase, tyrosinase inhibitory, urease inhibitory and cytotoxic activities. Among 59 extracts prepared from the different parts of the mentioned Euphorbia species, E. seguieriana subsp. seguieriana leaf (IC50: 10.41 +/- 0.93 mu g/mL) in lipid peroxidation inhibitory by beta-carotene-linoleic acid assay exhibited the highest activity, while E. grisophylla root in DPPH free radical scavenging (IC50: 0.79 +/- 0.01 mu g/mL), E. grisophylla seed in ABTS cation radical scavenging (IC50: 8.93 +/- 0.02 mu g/mL), E. fistulosa root both in acetyl- and butyryl-cholinesterase inhibitory (53.71 +/- 1.89% and 77.63 +/- 0.60% inhibition, respectively), E. denticulata leaf in urease inhibitory (96.89 +/- 2.00% inhibition), and E. macroclada mixed in tyrosinase inhibitory (86.99 +/- 3.77% inhibition) activities. However in cytotoxic activity studies, E. denticulata against PDF fibroblast cell lines (IC50: 23.04 +/- 0.03 mu g/mL), E. craspedia against HT-29 cancer cell line (IC50: 13.74 +/- 0.02 mu g/mL), E. fistulosa against MCF-7 and DLD-1 cancer cell lines (IC50: 14.04 +/- 0.04 mu g/mL and IC50: 20.23 +/- 0.08 mu g/mL, respectively) indicated quite good activity. According to the LC-MS/MS results, these species were rich in quinic acid, malic acid and tannic acid, rutin, hesperidin and hyperoside. Incidentally, it was found that the E. eriophora possessed very strong irritating potential. A chemometric approach using principal component analysis (PCA) and hierarchical clustering analysis (HCA) techniques were also studied on collected data to reveal the relationship between chemical contents of different parts of these Euphorbia species, and their biological activities, together with regional differences. Overall, these species could be suggested as valuable sources of natural-bioactive agents for developing new functional, pharmacological and health promoting ingredients.
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    Heavy Metals, Trace and Major Elements in 16 Wild Mushroom Species Determined by ICP-MS
    (Atomic Spectroscopy Press Ltd, 2018) Tel-Cayan, Gulsen; Ullah, Zain; Ozturk, Mehmet; Yabanli, Murat; Aydin, Firat; Duru, Mehmet Emin
    Eight minerals (Na, Mg, Ca, V, Mn, Fe, Zn, Se) and eight heavy metals (Al, Cr, Ni, As, Sr, Co, Cu, Pb) were studied in 16 wild mushroom species: Agarlats blsporus, Agaricus bitorquis, Agaricus essettei, Armtllaria tabescens, Craterellus cornucoptoides, Ilebeloma eburneum, Hebeloma fragilipes, Hypboloma fasciculare, Lepista nuda, Leacoagaricus leucotbites, Melanoleuca gramtnicola, Ompbalotus oleartus, Pbelltnus torulosus, Ramaria flava, Russula foetens, and Trametes ventcolor collected from Usak, Turkey, using ICP-MS. The mineral content of the mushroom samples was determined by ICP-MS and ranged from 46-1717 mg/kg for Na, 122-1121 mg/kg for Mg, 15-316 mg/kg for Ca, 0.09-1.04 mg/kg for V, 3.60-76.40 mg/kg for Mn, 17.3-395 mg/kg for Fe, 3.4-70.7 mg/kg for Zn, 0.03-0.56 mg/kg for Se. The heavy metals contents in the mushroom species were between 108-575 mg/kg for Al, 0.08-0.61 mg/kg for Cr, 0.18-3.95 mg/kg for Ni, 0.19-4.43 mg/kg for As, 2.41-14.9 mg/kg for Sr, 0.02-3.44 mg/kg for Co, 0.17-9.89 mg/kg for Cu, 0.05-3.33 mg/kg for Pb. All values of the inedible mushrooms, except the Cr and Pb concentrations of Lencoagarlcus leucothttes, were within the permitted WHO limits. Thus, the mushrooms analyzed are safe for human consumption.
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    In vitro antioxidant, anticholinesterase, tyrosinase activity studies, and LC-MS/MS simultaneous determination of 37 bioactive compounds in Indigofera heterantha
    (Elsevier, 2022) Ullah, Zain; Ali, Saqib; Hussain, Atarad; Ozturk, Mehmet; ERTAS, Abdulselam; Alamzeb, Muhammad; Rashid, Mamoon Ur
    The flowering plant Indigofera heterantha generally known as Indigo of Himalayan, was extracted with nhexane, ethyl acetate, and methanol by using Soxhlet apparatus. The extracts were studied for their antioxidants and enzyme inhibition activities. Against DPPH free radical-scavenging activity methanol extract was found moderately active (IC50: 158.41 +/- 1.1.66 mu g/mL). The ethyl acetate and n-hexane extracts exhibited the best ABTS radical scavenging activity (IC50: 31.32 +/- 2.50 and 52.0 +/- 0.89 mu g/mL respectively). Against the metal chelating activity, n-hexane extract was active IC50: 52.36 +/- 0.95 mu g/mL. The n-hexane and ethyl acetate extracts demonstrated the best b-carotene antioxidant activity (IC50: 22.32 +/- 0.84 and 60.66 +/- 0.35 mu g/mL respectively). Against acetylcholinesterase (AChE), ethyl acetate and methanol extracts were moderate active (IC50: 133.58 +/- 0.870, and 137.97 +/- 0.97 mu g/mL respectively). The ethyl acetate extract showed Butyrylcholinesterase (BChE) inhibitory activity with IC50 value of 121.9 +/- 1.13 mu g/mL. Against tyrosinase activity, ethyl acetate and n-hexane extracts activity with an IC50 value of 79.25 +/- 0.15 and 131.48 +/- 0.88 mu g/mL respectively. The phenolic contents of the methanolic extract of I. heterantha were also determined by using LC-MS/MS. The major constituents were Quinic acid (57,333.04 mu g/g), malic acid (1135.16 mu g/g), gallic acid (201.13 mu g/g), isoquercitrin (113.63 mu g/g), Rutin (92.97 mu g/g), and Salicylic acid (40.45 mu g/g). Keeping in view the overall biological activities of I. heterantha, it might be used in food industries and pharmaceuticals as a potential functional food ingredient.(c) 2022 SAAB. Published by Elsevier B.V. All rights reserved.