Bulunan: 32 Adet 0.001 sn
Koleksiyon [4]
Tam Metin [1]
Yazar [20]
Yayın Türü [2]
Konu Başlıkları [20]
Yayın Tarihi [15]
Dergi Adı [20]
Yayıncı [7]
Dil [1]
Yazar Departmanı [1]
Phenolic compounds from Hypericum calycinum and their antioxidant activity

Kirmizibekmez, H. | Bassarello, C. | Piacente, S. | Celep, E. | Atay, I. | Mercanoglu, G. | Yeşilada, E.

Article | 2009 | Natural Product Communications4 ( 4 ) , pp.531 - 534

From the MeOH extract of Hypericum calycinum, two caffeoylquinic acid derivatives, butyl chlorogenate (1), and chlorogenic acid (2), seven flavonoids, quercetin (3), quercitrin (4), hyperoside (5), isoquercitrin (6), miquelianin (7), rutin (8) and I3,II8-biapigenin (9) and two flavanols, (+)-catechin (10) and (-)-epicatechin (11) were isolated. Identification of the isolates was carried out by spectroscopic analysis including 1D and 2D NMR experiments as well as mass spectrometry. Free radical scavenging activities of the isolated compounds were determined in in-vitro 1,1-diphenyl-2-picrylhydrazyl (DPPH) and nitric oxide (NO) scaven . . .ging models. The compounds showed strong DPPH and moderate NO scavenging activities in a concentration dependent manner. (+)-Catechin and (-)-epicatechin were found to be the most active compounds with IC50 values of 4.16 and 4.67 µM for DPPH and 190 and 170 µM for NO scavenging activities, respectively Daha fazlası Daha az

Quantitative structure–activity relationship between antioxidant capacity of phenolic compounds and the plasmonic properties of silver nanoparticles

Bhutto, A.A. | Kalay, S. | Sherazi, S.T.H. | Çulha, Mustafa

Article | 2018 | Talanta189 , pp.174 - 181

Plasmonic response of silver nanoparticles (AgNPs) reduced with phenolic compounds were evaluated and correlated with the antioxidant capacities of corresponding phenolic compounds and their relative chemical structures. The reference methods including DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)) radical scavenging assays were used for the measurement of antioxidant capacity of phenolic compounds which was positively correlated with redox characteristics of these compounds against the formation of AgNPs. It is found that the higher plasmonic response of AgNPs corresponds to th . . .e highest antioxidant capacity of phenolic acids, which in turn depends on chemical structures and degree of hydroxylation. The higher degree of hydroxylation in chemical structures of phenolic compounds demonstrated the higher radical scavenging capacity and higher tendency to reduce Ag+ to AgNPs. The influence of reaction time and temperature on reducing efficiency of the tested phenolic compounds is found to be different. Some phenolic compounds such as quercetin, rutin and gallic acid reacted fast (< 1.0 min) while others were found slow reacting. This study establishes the relationship between the antioxidant capacity of phenolic acids and corresponding optical response by means of plamonics, which can be used as an innovative antioxidant detection assay for samples rich in phenolic compounds. © 201 Daha fazlası Daha az

Antimicrobial and antioxidant activity of the essential oil and methanol extract of Nepeta cataria

Adiguzel, A. | Ozer, H. | Sokmen, M. | Gulluce, M. | Sokmen, A. | Kilic, H. | Baris, O.

Article | 2009 | Polish Journal of Microbiology58 ( 1 ) , pp.69 - 76

Catnip (Nepeta cataria) is an important medicinal herb belonging to the mint family, Lamiaceae. In this study, the in vitro antimicrobial and antioxidant activities of the essential oil and methanol extract from Nepeta cataria, and its essential oil composition were investigated. The essential oil, which has 4a?,7?,7aß-nepetalactone (70.4%), 4a?,7?,7aß-nepetalactone (6.0%), thymol (2.3%), and 4a?,7?, 7aß-nepetalactone (2.5%), as main components, exhibited activity against eleven bacteria, and twelve fungi and a yeast, C. albicans; with Minimum Inhibitory Concentrations (MIC) values ranging from 12.50 to 250 µl/ml; the methanol extra . . .ct showed weaker activity. The samples were also subjected to a screening for their possible antioxidant activities by using 2.2-diphenyl-1-picrylhydrazyl (DPPH) and ß-carotene/linoleic acid assays. In DPPH assay, the extract showed slight antioxidant activity whereas the essential oil remained inactive. In the latter case, both the extract and the essential oil exerted weak activity having inhibiton ratios of linoleic acid oxidation at 16.4% and 27.0%), respectively. The weak antioxidative nature of the extract could be attributed to the low phenolic content, estimated as gallic acid equivalent at 22.6 ± 2.07 µg/ml or 2.26%. In both systems, antioxidant capacity of BHT was determined in parallel experiments Daha fazlası Daha az

Beneficial effects of Aesculus hippocastanum L. seed extract on the body's own antioxidant defense system on subacute administration

Küçükkurt, I. | Ince, S. | Keleş, H. | Küpeli Akkol, E. | Avci, G. | Yeşilada, E. | Bacak, E.

Article | 2010 | Journal of Ethnopharmacology129 ( 1 ) , pp.18 - 22

Aim of the study: Seeds of Aesculus hippocastanum L. have long been used in European phytotherapy to treat inflammatory and vascular problems. In Turkish folk medicine, tea prepared from the crushed seeds was used to pass kidney stone and against stomach ache, while a fraction of seed was swallowed to alleviate hemorroids symptoms.In order to evaluate the in vivo effects of escin mixture from Aesculus hippocastanum seed on the blood and tissue antioxidant defense systems in standard pellet diet (SPD) and in high-fat diet (HFD) consumed male mice. Materials and methods: Escin mixture was obtained from the ethanol extract of seeds. Es . . .cin mixture was administered orally to male mice fed either standard pellet diet (SPD) or high-fat diet (HFD) at 100. mg/kg doses daily for 5 weeks and the tissue (liver, kidney and heart) and blood samples were collected at the end of experimental period. The effect of escin mixture on the plasma antioxidant activity; blood and tissue malondialdehyde (MDA) and reduced glutathione (GSH) levels; erythrocyte and tissue superoxide dismutase (SOD) and catalase activity (CAT) in SPD and HFD consumed animals were experimentally studied. Results: Escin mixture prohibited the adverse effects of oxidative stress and showed a protective effect on the liver architecture both in SPD and HFD consumed male mice. Escin mixture prohibited the adverse effects of oxidative stress and showed a protective effect on the liver architecture both in SPD and HFD consumed male mice. Combined administration of high-fat diet with escin mixture decreased blood ( Daha fazlası Daha az

Phytochemical characterization and antioxidant activities of the fruit extracts of several Crataegus taxa

Bardakci, H. | Celep, E. | Gözet, T. | Kan, Y. | Kırmızıbekmez, H.

Article | 2019 | South African Journal of Botany124 , pp.5 - 13

This study was designed to comparatively evaluate the phytochemical composition and antioxidant potentials of fruit extracts from five Crataegus taxa (C. monogyna, C. orientalis, C. pontica, C. rhipidophylla and C. turcicus)growing wild in the flora of Turkey. Antioxidant activities of the samples were investigated using DPPH radical scavenging, FRAP, CUPRAC and total antioxidant capacity tests. Total phenol, phenolic acid, flavonoid, and proanthocyanidin contents were measured spectrophotometrically. Additionally, the presence of some phenolic compounds in the extracts was investigated by LC–MS/MS. Furthermore, the extracts used fo . . .r the antioxidant activity studies were standardized for chlorogenic acid and hyperoside by HPTLC densitometry. Among the tested extracts, C. turcicus contained the highest phenolic (398.48 ± 0.98 GAE/g extract)and total flavonoid contents (23.87 ± 2.74 QE/g extract)content while C. monogyna contained by far the highest total proanthocyanidin (175.65 ± 10.59 EGCG-E/g extract), hyperoside (0.42%)and chlorogenic acid (0.90%)contents. Crataegus monogyna exhibited the highest antioxidant activity in FRAP, CUPRAC, and TOAC tests. Good correlation was found between the phenolic content and antioxidant parameters. This is the first report related with comparison of these five species in respect to phenolic profile and antioxidant activity. © 2019 South African Association of Botanist Daha fazlası Daha az

Antioxidant and nutritional characteristics of garden cress (Lepidium sativum)

Sat, I.G. | Yildirim, E. | Turan, M. | Demirbas, M.

Article | 2013 | Acta Scientiarum Polonorum, Hortorum Cultus12 ( 4 ) , pp.173 - 179

Garden cress (Lepidium sativum), a member of the Brassicaceae family, is an underutilised crop in Europe and Turkey. The dry matter content, crude protein, ascorbic acid, minerals (N, P, K, Ca, Mg, Na, Fe, B, Cu, Na, Zn, Mn), the total phenolic content and the total antioxidant capacity of two garden cress cultivars, Izmir and Dadas, were studied. The results of mineral element analysis of both cultivars revealed that they had a high P, K, Ca, Mg and Na content. Both cultivars studied appeared to have exceptionally high levels of protein when compared with common vegetables. The mean ascorbic acid content of Dadas and Izmir cultivar . . .s were 54 and 74 mg 100 g-1 f.w., respectively. The total phenolic content of the garden cress leaves varied from 0.573 (Dadas) to 0.774 (Izmir) mg GAE · g-1 fw and from 6.332 (Dadas) to 7.401 (Izmir) mg GAE · g-1 dw. Antioxidant activities by 2-diphenyl-1-picryhydrazyl (DPPH) free-radical-scavenging assays for EC50 were determined as 330.99 (Dadas) and 346.65 (Izmir) for fw, and 128.08 and 85.97 (Izmir) for dw, respectively. Based on the results of the experiment reported herein, they may serve as a potential dietary source of some mineral and natural phenolic antioxidants. Our results imply garden cress as potential source for alternative dietary supplements of minerals and natural phenolic antioxidants Daha fazlası Daha az

Profiling of Turkish propolis subtypes: Comparative evaluation of their phytochemical compositions, antioxidant and antimicrobial activities

Ristivojevic, P. | Dimkic, I. | Guzelmeric, E. | Trifkovic, J. | Knezevic, M. | Beric, T. | Stankovic, S.

Article | 2018 | LWT95 , pp.367 - 379

Comprehensive analysis of phenolic profiles of botanically different subtypes of Turkish propolis samples were performed using UHPLC–LTQ/Orbitrap/MS/MS method, and additionally total phenolic (TPC) and total flavonoid contents (TFC) as well as their antioxidative activities were evaluated by spectrophotometry. Antimicrobial activity of Turkish propolis against oral cavity bacteria from the genus Streptococcus (S. pyogenes, S. sanguinis, S. mutans) and Candida albicans ATCC 10231 was determined by diffusion and microdilution methods. Extensive fingerprint analysis of Turkish propolis revealed the presence of fifty one phenolic compou . . .nds, with fifteen quantified which confirm their affiliation to the two subtypes of the European propolis. All analysed samples have shown antimicrobial potential against all tested bacteria, with S. pyogenes being the most sensitive one. Turkish propolis, especially its orange subtype, can be considered as the high-quality product due to its rich phenolic and flavonoid content, strong antioxidative and antimicrobial activities. Turkish propolis could be, therefore, a good raw material for food and pharmaceutical industry. © 2018 Elsevier Lt Daha fazlası Daha az

Characterization and Biological Activity of Achillea teretifolia Willd. and A. nobilis L. subsp. neilreichii (Kerner) Formanek Essential Oils

Demirci, F. | Demirci, B. | Gürbüz, I. | Yeşilada, E. | Başer, K.H.C.

Article | 2009 | Turkish Journal of Biology33 ( 2 ) , pp.129 - 136

The aerial parts of the endemic Achillea teretifolia Willd. and A. nobilis L. subsp. neilreichii (Kerner) Formanek collected from Beysehir were investigated for their essential oil compositions and several biological activities. The essential oils were analyzed both by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS). The main components were identified as 1,8-cineole (34%), camphor (11%), terpinen-4-ol (8%), and ?-thujone (5%) for A. teretifolia essential oil, while fragranyl acetate (32%), fragranol (24%), and p-eudesmol (8%) for A. nobilis subsp. neilreichii essential oil, respectively. The essential oils . . .were also evaluated for their in vitro antimicrobial activity and their ability to scavenge 1,1-diphenyl-2- picrylhydrazyl (DPPH) radicals using microdilution techniques as an index for the evaluation of antioxidant activity. Both essential oils were found to be effective against the tested human pathogenic microorganisms (MIC 0.5 to >2 mg/ml) and DPPH (IC50 > 0.5 mg/ml) assay as compared to the references Daha fazlası Daha az

Inhibitory effect of calamintha nepeta subsp.glandulosa essential oil on lipoxygenase

Demirci, B. | Temel, H.E. | Portakal, T. | Kirmizibekmez, H. | Demirci, F. | Başer, K.H.C.

Article | 2011 | Turkish Journal of Biochemistry36 ( 4 ) , pp.290 - 295

Objective: Scavenging of free radicals and inhibition of lipoxygenase are important target in the treatment of a variety of inflammatory diseases. Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) P.W. Ball of Lamiaceae was previously reported in the treatment of several diseases in folk medicine. In this study, the essential oil of C. nepeta subsp. glandulosa was investigated for its radical scavenging activity and inhibitory effect on lipoxygenase. Material and Method: The essential oil of Calamintha nepeta (L.) Savi subsp. glandulosa (Req.) P.W. Ball was obtained by hydrodistillation and analyzed by gas chromatography - mass s . . .pectrometry. Essential oil and its major component of biological activity was determined using an UV-spectrophotometric assay.Results: Oxygenated monoterpenes pulegone (54%) and menthone (16%) were found to be the major constituents of the oil. C. nepeta essential oil demonstrated inhibition on lipoxy-genase at IC50=69.6± 9.1 µg/mL, whereas its main component pulegone showed no effect at the same tested concentration. Neither the essential oil nor pulegone displayed radical scavenging activity (>0.5 mg/mL). Major component pulegone of C. nepeta essential oil showed no inhibitory effect on lipoxygenase activity, but other components besides of their low concentration demonstrated an inhibitory effect on lipoxygenase activity in 1/29 ratio when compared to the standard substance.Conclusion: Data of our study indicated that essential oil of C. nepeta may contain potent lipoxygenase inhibitor substances. Further, investigation of other components except the major constituent pulegone on lipoxygenase activity may result in the identification of effective lipoxygenase inhibitors Daha fazlası Daha az

Chemical composition, antioxidant, antimicrobial activities of the essential oil of salvia hypargeia fisch. & mey

Atas, A.D. | Goze, I. | Alim, A. | Cetinus, S.A. | Vural, N. | Murat Goze, H. | Korkoca, H.

Article | 2011 | Journal of Essential Oil-Bearing Plants14 ( 3 ) , pp.289 - 296

The aim of this study was to investigate the chemical composition, antioxidant and antimicrobial activities of the essential oil of Salvia hypargeia from Turkey. According to the results of GC-EIMS analysis, the major compounds of the oil were determined as Ot-pinene (15.9 %), ß-pinene (22.3 %), pulegone (13.5 %) and ß-ylangene (17.8 %). Essential oil could not show radical scavenging effect in DPPH system. On the other hand, inhibition capacity of the essential oil against linoleic acid oxidation was measured as 21.0 %. In the case of antimicrobial activity, the most sensitive microorganism was B. subtilis which has the lowest MIC . . .value (35.80 µg/ml). This is followed by S. aureus and C. diphteriae (8.45 and 14.20 µg/ml, respectively). © 2011 Taylor & Francis Group, LLC Daha fazlası Daha az

Antihypercholesterolaemic and antioxidant activity assessment of some plants used as remedy in Turkish folk medicine

Avci, G. | Kupeli, E. | Eryavuz, A. | Yeşilada, Erdem | Kucukkurt, I.

Article | 2006 | Journal of Ethnopharmacology107 ( 3 ) , pp.418 - 423

Ethanolic and aqueous extracts from five plant species used in Turkish traditional medicine were evaluated for in vivo hypercholesterolaemic and antioxidant activities: Agrostemma githago L., Potentilla reptans L., Thymbra spicata var. spicata L., Urtica dioica L. and Viscum album var. album L. We assayed the effects of the administration of plant extracts on serum total cholesterol, triglyceride, HDL-C, LDL-C, glucose, AST and ALT concentrations in mice fed with cholesterol-rich diet. In addition, plasma TAA, MDA and NOx levels in the same animals were assayed. All the aqueous plant extracts did not affect the serum cholesterol con . . .centration. However, the ethanolic extracts of Agrostemma githago, Thymbra spicata and Viscum album decreased the serum cholesterol concentration in the mice fed with high-cholesterol diet without inducing any gastric damage. The ethanolic extracts of Thymbra spicata, Viscum album, Potentilla reptans and Urtica dioica and the aqueous extract of Agrostemma githago increased the serum HDL concentration, whereas the ethanolic extracts of Agrostemma githago, Thymbra spicata, Viscum album and Urtica dioica decreased the serum LDL-C concentration. Thymbra spicata and Viscum album were observed to decrease the serum triglyceride concentration. Among the plant extracts studied, the ethanolic extracts of Thymbra spicata significantly decreased the MDA level in mice. The ethanolic extract of Potentilla reptans increased in NOx. None of these plants showed statistically prominent activity on plasma TAA. Results of the present study indicated that the ethanolic extracts of Agrostemma githago, Thymbra spicata and Viscum album showed potent hypocholesterolaemic activity in the mice fed with a diet containing high-cholesterol. © 2006 Elsevier Ireland Ltd. All rights reserved Daha fazlası Daha az

Evaluation of antioxidant and antimicrobial activities of Tamus communis L. ssp. cretica (L.) Kit Tan and its mineral composition

Küçükboyaci, N. | Turan Dural, N.N. | Köroğlu, A. | İşcan, G. | Aydin, A.

Article | 2015 | Turkish Journal of Pharmaceutical Sciences12 ( 2 ) , pp.113 - 122

The aim of the present work was to examine antioxidant and antimicrobial properties of Tamus communis L. ssp. cretica (L.) Kit Tan (Dioscoreaceae). The applied methods for the antioxidant activity of aqueous extract from the aerial parts of the plant were 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, flow injection analysis-luminol chemiluminescence (FIA-CL) and thiobarbituric acid (TBA) assays. Total phenolic content of the aqueous extract was determined with spectrophotometric method. The antimicrobial activity of the n-hexane, chloroform, ethyl acetate, and ethanol extracts of the aerial parts of the plant was assessed towards . . . selected bacteria. In addition, mineral composition of the raw plant was examined by atomic absorption spectroscopy. Aqueous extract of T. communis ssp. Cretica was found to possess DPPH free radical scavenging activity (IC50= 2.85±1.30 mg/mL), inhibitory effect on H2O2- and HOCl-luminol chemiluminescence (-log IC50=3.8±0.09 and IC50=1.3x10-3±4.9x10-4 mg/mL), and inhibitory activity toward lipid peroxidation (IC50=3.82±1.67 µg/mL) compared to the references. Total phenolic content of the aqueous extract was found to be 56.66±0.21 mg gallic acid/g extract. The n-hexane, chloroform, ethyl acetate, and ethanol extracts showed moderate activity having MIC values of 250-500 µg/mL against selected microorganisms. According to our results of mineral composition, the raw plant has low amount of toxic elements (Pb, Cd and Al), macro (Ca and Mg), and microelements (Cu, Fe, Mn and Zn). © 2015, Turkish Pharmacists Association. All rights reserved Daha fazlası Daha az

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