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Öğe Antioxidant potentials and anticholinesterase activities of methanolic and aqueous extracts of three endemic Centaurea L. species(Pergamon-Elsevier Science Ltd, 2013) Aktumsek, Abdurrahman; Zengin, Gokhan; Guler, Gokalp Ozmen; Cakmak, Yavuz Selim; Duran, AhmetThe methanol and aqueous extracts of three endemic Centaurea species (C. polypodiifolia var. pseudobehen, C pyrrhoblephara and C antalyense) were investigated for their antioxidant and cholinesterase inhibitory activities. The antioxidant activities of these extracts were evaluated by in vitro models including, phosphomolybdenum assay, free radical scavenging assays (DPPH and ABTS), beta-carotene/linoleic acid test system, metal chelating assay, FRAP assay, ferric and cupric reducing power. Cholinesterase inhibitory activities were examined using Ellman's calorimetric method. Total phenol, flavonoid, and saponin contents were also measured. Among the six Centaurea extracts evaluated, the highest antioxidant abilities were obtained from C polypodiifolia var. pseudobehen. Methanolic extracts from C polypodiifolia var. pseudobehen and C antalyense had a noticeable inhibition towards AChE and BChE. These findings suggest that Centaurea species could be an anticholinesterase agent and antioxidant resource in some industries, such as food, pharmacology, and cosmetics. (C) 2013 Elsevier Ltd. All rights reserved.Öğe Assessment of the antioxidant potential and fatty acid composition of four Centaurea L. taxa from Turkey(Elsevier Sci Ltd, 2013) Aktumsek, Abdurrahman; Zengin, Gokhan; Guler, Gokalp Ozmen; Cakmak, Yavuz Selim; Duran, AhmetThis paper focused on the assessment of antioxidant property and fatty acid composition of four Centaurea species. The antioxidant activity of its methanol extract was evaluated by several in vitro experiments including phosphomolybedum assay, DPPH assay, beta-carotene/linoleic acid, ferric and cupric reducing power. Total phenolic and flavonoid contents were also evaluated. The methanol extract of Centaurea pulcherrima var. pulcherrima showed the superior free radical scavenging activity, linoleic acid inhibition capacity, reducing power and also had the highest total phenolic content. A significant relationship between antioxidant capacity and total phenolic components was found. The oils of Centaurea taxa were also analysed for fatty acid concentration by gas chromatography. The principal fatty acids in the species were palmitic acid (23.38-30.49%) and linoleic acid (20.19-29.93%). These findings suggest that the Centaurea species could be used as a potential source of new natural antioxidants and unsaturated fatty acids in food industry, cosmetics and pharmaceutical preparations. (c) 2013 Elsevier Ltd. All rights reserved.Öğe Bioactive constituents of Lathyrus czeczottianus and ethyl acetate and water extracts and their biological activities: An endemic plant to Turkey(Elsevier, 2021) Ceylan, Ramazan; Zengin, Gokhan; Guler, Gokalp Ozmen; Aktumsek, AbdurrahmanLathyrus species are economically important as food, fodder, and folk medicine. The antioxidant properties (radical scavenging effectiveness, reducing power potentials, metal chelating ability, phosphomolydenum capacity) phytochemical characterization (phenolic composition), and enzyme inhibition abilities of the water and ethyl acetate extracts of Lathyrus czeczottianus (LC) were tested. The phenolic ingradients of LC extracts were evaluated by HPLC-DAD (High-performance liquid chromatography with diode array detector). Chlorogenic acid, epicatechin, and benzoic acid were found as main phenolic compounds in both extracts. Generally, the water extract revealed strong antioxidant potential. The antioxidant effectiveness could be explained by high total phenolic level in the extract. Regarding enzyme inhibitory results, the ethyl acetate extract indicated good inhibitory activities on cholinesterase (for AChE: Acetylccholinesterase 1.15 mg galathamine equivalents (GALAE/g extract) and for BChE: Butyrylcholinesterase 0.19 mg GALAE/g extrac), tyrosinase (54.48 mg kojic acid equivalents (KAE/g)), and alpha-amylase (0.34 mmol acarbose equivalents (ACEs/g)), while the water extract had just good inhibition on alpha-glucosidase (6.49 mmol ACEs/g). In conclusion, L. czeczottianus could be good valuable of bioactive molecules for pharmaceuticals, food and agriculture, and nutraceutical applications. (C) 2020 SAAB. Published by Elsevier B.V. All rights reserved.Öğe Comparison of Fatty Acid Compositions and ?3/?6 Ratios of Wild Brown Trout and Cultured Rainbow Trout(Central Fisheries Research Inst, 2017) Guler, Gokalp Ozmen; Zengin, Gokhan; Cakmak, Yavuz Selim; Aktumsek, AbdurrahmanFish are a unique dietary source beneficial to human health. These valuable effects originate from omega 3 polyunsaturated fatty acids, particularly the eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in the fish oil. In this study, fatty acid composition of the muscle lipids of Salmo trutta macrostigma (wild brown trout) and Oncorhynchus mykiss (cultured rainbow trout) in Gezende Dam Lake were determined by gas chromatographic technique. In both species, palmitic acid (16.26-18.94%), oleic acid (17.88-20.49%) and DHA (14.08-18.49%) were identified as major saturated fatty acid (SFA), monounsaturated fatty acid (MUFA) and polyunsaturated fatty acid (PUFA), respectively. Wild fish contained significantly more linolenic acid, arachidonic acid, eicosapentaenoic acid, docosapentaenoic acid, total omega 3 fatty acids and has higher omega 3/omega 6 ratio than cultured fish. In conclusion, wild brown trout may have a higher nutritional value considering total omega 3 fatty acids (35.52-27.43%) and omega 3/omega 6 ratio (3.84-1.56) compared to cultured rainbow trout.Öğe Determination of fatty acid profiles of total, neutral, and polar lipids in different tissues of Vimba vimba (L., 1758) from Egirdir Lake (Isparta, Turkey)(Tubitak Scientific & Technological Research Council Turkey, 2013) Gorgun, Salih; Akpinar, Nukhet; Zengin, Gokhan; Akpinar, Mehmet Ali; Gunlu, Ali; Guler, Gokalp Ozmen; Aktumsek, ApdurahmanFatty acid profiles of total, neutral, and polar lipids in the liver, muscle, and intestine of female individuals of Vimba vimba (L., 1758) were determined by gas chromatography. C16:0, C16: 1 n-7, C18:1 n-7, and C18:1 n-9 were the most abundant fatty acids in total and neutral lipids in all tissues investigated. In addition to these acids, C20:4 n-6 (arachidonic acid) and C22:6 n-3 (docosahexaenoic acid) were the other fatty acids having high percentages in the polar lipid fraction of the tissues. The highest and lowest n-3 to n-6 ratios, which are a good indicator of the quality of fish oils, were determined in the muscle (1.68) and liver (0.68) in the polar lipid fraction, respectively. It was determined that the species had low levels of the n-3 forms of polyunsaturated fatty acids in the investigated tissues. For a better understanding of fatty acid metabolism of V. vimba, more detailed studies are required in terms of feeding experiments.Öğe Enzyme Inhibitory Properties, Antioxidant Activities, and Phytochemical Profile of Three Medicinal Plants from Turkey(Hindawi Ltd, 2015) Zengin, Gokhan; Guler, Gokalp Ozmen; Aktumsek, Abdurrahman; Ceylan, Ramazan; Picot, Carene Marie Nancy; Mahomoodally, M. FawziWe aimed to investigate the inhibitory potential of three medicinal plants (Hedysarum varium, Onobrychis hypargyrea, and Vicia truncatula) from Turkey against key enzymes involved in human pathologies, namely, diabetes (alpha-amylase and alpha-glucosidase), neurodegenerative disorders (tyrosinase, acetylcholinesterase, and butyrylcholinesterase), and hyperpigmentation (tyrosinase). The antioxidant potential, phenolic and flavonoid content of ethyl acetate, and methanolic and aqueous extracts were investigated using in vitro assays. The total antioxidant capacity (TAC), beta-carotene/linoleic acid bleaching activity, 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH center dot), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(center dot+)), cupric ion reducing antioxidant capacity (CUPRAC), ferric reducing antioxidant power (FRAP), and metal chelating activity on ferrous ions were used to evaluate the antioxidant capabilities of the extracts. The half-maximal inhibitory concentrations (IC50) of the extracts on cholinesterase, tyrosinase, and alpha-amylase were significantly higher than the references, galantamine, kojic acid, and acarbose, respectively. The half-maximal effective concentrations (EC50) of the extracts on TAC, CUPRAC, and FRAP were significantly higher than trolox. The phenol and flavonoid contents of the plant extracts were in the range 20.90 +/- 0.190-83.25 +/- 0.914mg gallic acid equivalent/g extract and 1.45 +/- 0.200-39.71 +/- 0.092mg rutin equivalent/g extract, respectively. The plants were found to possess moderate antioxidant capacities and interesting inhibitory action against key enzymes.Öğe Evaluation of Fatty Acid Compositions of Yogurts in Turkey(Asian Journal Of Chemistry, 2014) Caglayan, Okan; Cakmak, Yavuz Selim; Guler, Gokalp Ozmen; Zengin, Gokhan; Aktumsek, AbdurrahmanIn this study, fatty acid composition and conjugated linoleic acid content of some yogurts in Turkey were determined. Total 50 yogurt samples belonging to 16 different national yogurt brands were analyzed by using GC. These samples categorized as whole yogurts, light yogurts, probiotic yogurts and fruity yogurts. Generally, palmitic acid (28.840-30.160 %), oleic acid (26.003-27.533 %) and stearic acid (11.413-12.077 %) were major fatty acids. Total conjugated linoleic acid percentages varied between 0.790 and 0.862 %. The results have shown that fatty acids compositions of yogurts have a desirable characteristic for healthy diet when their levels of conjugated linoleic acid contents are considered.Öğe Evaluation of Fatty Acid Compositions of Yogurts in Turkey(Asian Journal Of Chemistry, 2014) Caglayan, Okan; Cakmak, Yavuz Selim; Guler, Gokalp Ozmen; Zengin, Gokhan; Aktumsek, AbdurrahmanIn this study, fatty acid composition and conjugated linoleic acid content of some yogurts in Turkey were determined. Total 50 yogurt samples belonging to 16 different national yogurt brands were analyzed by using GC. These samples categorized as whole yogurts, light yogurts, probiotic yogurts and fruity yogurts. Generally, palmitic acid (28.840-30.160 %), oleic acid (26.003-27.533 %) and stearic acid (11.413-12.077 %) were major fatty acids. Total conjugated linoleic acid percentages varied between 0.790 and 0.862 %. The results have shown that fatty acids compositions of yogurts have a desirable characteristic for healthy diet when their levels of conjugated linoleic acid contents are considered.Öğe HPLC-DAD profiles and pharmacological insights of Onobrychis argyrea subsp isaurica extracts(Elsevier Sci Ltd, 2018) Guler, Gokalp Ozmen; Zengin, Gokhan; Karadag, Firat; Monica, Adriano; Picot, Carene Marie Nancy; Mahomoodally, Mohamad FawziOnobrychis argyrea Boiss. subsp. Isaurica (Fabaceae), endemic to the eastern Mediterranean region, is a poorly studied medicinal plant. This study sets out to investigate into antioxidant and inhibitory activities of O. argyrea extracts (ethyl acetate, methanol, and water) against key enzymes linked to diabetes (alpha-amylase, alpha-glucosidase), Alzheimer's disease (acetylcholinesterase, butyrylcholinesterase), and skin hyperpigmentation (tyrosinase). Phytochemical composition was determined by HPLC-DAD and in silico approach used to provide additional insight of the possible interaction of the identified phenolic compounds with the studied enzymes. The methanol extract showed potent inhibitory action against acetylcholinesterase (1.55 mg GALAE/g extract), tyrosinase (61.61 mg KAE/g extract), and glucosidase (20.17 mmol ACAE/g extract). The methanol extract of O. argyrea exhibited potent radical scavenging potential (126.51 mg TE/g extract for DPPH scavenging assay) and reducing capacities (311.36 and 200.70 mg TE/g extract, for CUPRAC and FRAP assays, respectively). Quercetin, apigenin, and benzoic acid were identified in significant amounts in the methanol extract of O. argyrea. Quercetin interacted with the catalytic pocket of glucosidase by establishing hydrogen bonds with Ser157, Ser241, Asp307, and pi-pi interactions with His280 and Tyr158. The observed inhibitory effects of O. argyrea extracts on the studied enzyme suggest that this plant could be a promising source of naturally occurring chemical compounds for the management of diabetes, Alzheimer's disease, skin hyperpigmentation disorders, as well as, oxidative stress-related complications.Öğe Shedding light on the biological and chemical fingerprints of three Achillea species (A-biebersteinii, A-millefolium and A-teretifolia)(Royal Soc Chemistry, 2017) Zengin, Gokhan; Aktumsek, Abdurrahman; Ceylan, Ramazan; Uysal, Sengul; Mocan, Andrei; Guler, Gokalp Ozmen; Mahomoodally, M. FawziRepresentatives of the Achillea genus are widely used as foods or nutraceuticals. Considering the increasing demand for herbal dietary supplements with health promoting effects, the objective of this research was to evaluate the biological and chemical profiles of different extracts (ethyl acetate, methanol and water) obtained from three Achillea species (A. biebersteinii, A. millefolium and A. teretifolia). The antioxidant (free radical scavenging (DPPH and ABTS), reducing power (CUPRAC and FRAP), metal chelating and phosphomolybdenum), enzyme inhibitory (anti-cholinesterase, anti-tyrosinase, anti-amylase and anti-glucosidase) and antimicrobial (antibacterial and antifungal) effects were assessed to investigate their biological profiles. Moreover, the total phenolic and flavonoid contents were determined and LC-MS analysis was performed for the chemical profile of the investigated extracts. The LC-MS analysis revealed the presence of several caffeoylquinic acids in these extracts. Generally, the methanol and water extracts exhibited stronger antioxidant abilities, which correlated with the higher levels of phenolic compounds when compared to the ethyl acetate extracts. In addition, the best antimicrobial activities were obtained for the ethyl acetate and methanolic extracts. However, the ethyl acetate extract had remarkable enzyme inhibitory potential. On the basis of our results, Achillea species may be promoted as promising sources of natural agents and used for the development of nutraceuticals or functional food ingredients.Öğe STUDIES ON ANTIOXIDANT PROPERTIES OF THE DIFFERENT SOLVENT EXTRACTS AND FATTY ACID COMPOSITION OF HYOSCYAMUS RETICULATUS L.(Wiley, 2012) Guler, Gokalp OzmenHyoscyamus reticulatus (Solanaceae) is distributed in the Mediterranean, East and Central Anatolia regions of Turkey. In the present study, antioxidant properties of the various extracts of H. reticulatus were evaluated by seven different chemical assays, namely total phenolics and flavonoids content, total antioxidant capacity, free radical (2,2-diphenyl-1-picrylhydrazyl)-scavenging assay, beta-carotene/linoleic acid test system, and ferric- and cupric ion-reducing power. The strongest antioxidant properties were obtained by ethanolic extract. The order of the antioxidant properties of extracts were ethanolic > methanolic > acetone. Fatty acid composition of the aerial parts of H. reticulatus was analyzed by gas chromatography. The main fatty acids of the oil gave the proportions C 12:0 (lauric acid), C 10:0 (capric acid) and C 11:0 (undecanoic acid). Results of the present study demonstrated that the extracts and oil of H. reticulatus may be used as a source of natural antioxidant and lauric acid in the food and pharmaceutical industries. PRACTICAL APPLICATIONS Hyoscyamus species contain important tropane alkaloids, which have antispasmodic, anticholinergic, analgesic and sedative effects. In this study, antioxidant properties of the various extracts of Hyoscyamus reticulatus were investigated by seven different chemical assays. The results of the present study may be important as an indication of pharmacological and food processing utility of the plant. H. reticulatus can be considered as a source of both natural antioxidants and lauric acid in food industry and pharmacological applications.Öğe A STUDY ON ANTIOXIDANT CAPACITIES AND FATTY ACID COMPOSITIONS OF TWO DAPHNE SPECIES FROM TURKEY: NEW SOURCES OF ANTIOXIDANTS AND ESSENTIAL FATTY ACIDS(Wiley, 2013) Zengin, Gokhan; Arkan, Tuba; Aktumsek, Abdurrahman; Guler, Gokalp Ozmen; Cakmak, Yavuz SelimDaphne (Thymealaceae) species have been widely used in traditional Anatolian medicine. The antioxidant capacity and fatty acid composition of two Daphne taxa (D.oleoides subsp. oleoides and D.serica) were studied. The antioxidant properties of four solvent extracts of Daphne species were assessed using different chemical assays including phosphomolybdate assay, free radical-scavenging assay, -carotene/linoleic acid test system, ferric and cupric reducing power. The total phenolic and flavonoid content of the extracts also were determined. Ethyl acetate, methanol and ethanol extracts obtained from the Daphne species possess strong antioxidant potential. Polyunsaturated fatty acids in the studied oils were the highest level in the fatty acid components. Essential fatty acids accounted for 27.46-45.31% of total fatty acids. These results indicated that the extracts of studied Daphne taxa can be exploited as a source of natural antioxidants and essential fatty acids in pharmacological and food industry.