Guzelmeric, E. | Ristivojevic, P. | Trifkovic, J. | Dastan, T. | Yilmaz, O. | Cengiz, O. | Yeşilada, Erdem

Article | 2018 | LWT - Food Science and Technology87 , pp.23 - 32

Propolis is a honeycomb product having very diverse chemical composition and possessing a broad spectrum of biological activities. This study comprehensively evaluated the phenolic profile of Turkish propolis by using a high performance thin-layer chromatographic (HPTLC) method in combination with image analysis and pattern recognition technique. Also, botanical origin of each propolis sample was determined by comparison of HPTLC fingerprints of propolis samples with that of plant bud extracts and also by palynological analysis. Moreover, HPTLC coupled with 2,2-diphenyl-1-picrylhydrazyl (DPPH') detection technique was used for scree . . .ning of antioxidant activity of each separated compounds directly on the plate. Results of the present study have demonstrated that Turkish propolis could be classified under three main types; i.e. orange (O) (originated from Populus nigra L.), blue (B) (originated from Populus tremula L.) and nonphenolic types. Palynological analysis have shown that dominant pollen grains (>%45) in propolis samples were: Fabaceae, Lamiaceae, Rosaceae, Castanea sativa Mill., Lotus corniculatus L., Salix spp. In addition, HPTLC-DPPH' results showed that O-type of propolis exerted higher antioxidant activity than the other propolis types. Moreover, quercetin, caffeic acid, caffeic acid phenyl ester, pinobanksin and galangin had significant contribution to the antioxidant activity of propolis. © 2017 Elsevier Lt Daha fazlası Daha az

Celep, E. | Aydin, A. | Yeşilada, Erdem

Article | 2012 | Food and Chemical Toxicology50 ( 9 ) , pp.3329 - 3335

This study was designed in order to investigate in vitro antioxidant potentials of 80% methanolic extracts prepared from three edible fruits, Cornus mas L., Diospyros kaki L., Laurocerasus officinalis Roem. For this purpose, 8 different tests were performed including 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging tests, ferric reducing antioxidant power (FRAP), cupric reducing antioxidant capacity (CUPRAC), metal-chelating capacity, determination of total antioxidant capacity, ß-carotene bleaching test in a linoleic acid emulsion system and trolox equivalent antioxidant capacity. In addition, for evaluating t . . .he phenolic profile, total phenolic, flavonoid and proanthocyanidin contents were measured spectrophotometrically. Among the three fruits analyzed, Diospyros kaki L. showed the highest activity in all tests, except ß-carotene bleaching test. Whereas, neither of three fruits showed metal-chelating activity. Also, a good correlation was found between the phenolic content and antioxidant parameters. © 2012 Elsevier Ltd Daha fazlası Daha az

Küpeli Akkol, E. | Orhan, D.D. | Gürubüz, I. | Yeşilada, Erdem

Article | 2010 | Pharmaceutical Biology48 ( 3 ) , pp.253 - 259

Honey-bee pollen mix (HBM) formulation is claimed to be effective for the treatment of asthma, bronchitis, cancers, peptic ulcers, colitis, various types of infections including hepatitis B, and rheumatism by the herb dealers in northeast Turkey. In the present study, in vivo antinociceptive, anti-inflammatory, gastroprotective and antioxidant effects of pure honey and HBM formulation were evaluated comparatively. HBM did not show any significant gastroprotective activity in a single administration at 250mg/kg dose, whereas a weak activity was observed after three days of successive administration at 500mg/kg dose. On the other hand . . ., HBM displayed significant antinociceptive (p Daha fazlası Daha az

Celep, E. | Akyuz, S. | İnan, Y. | Yeşilada, Erdem

Article | 2017 | Turkish Journal of Biochemistry42 ( 4 ) , pp.375 - 380

Herbal infusions are among the most widely consumed beverages throughout the world. Their popularity arises due to not only their pleasant aroma and taste, but also their high phenolic content and antioxidant activity. A vast number of in vitro studies revealed their high phenolic content, together with strong antioxidant activity. However, the majority of them seem to ignore some important physiological parameters, such as bioavailability or bioaccessibility. The present study was planned to evaluate the stability of phenolic content and antioxidant activities of seven most widely preferred herbal infusions. A stimulated version of . . . gastrointestinal infusion was added to the study for comparative purposes. The results indicated the loss of both phenolic content and antioxidant activity of herbal infusions after being submitted to digestion. © 2017, Turkish Biochemistry Society. All rights reserved Daha fazlası Daha az

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

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

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

Sokmen, M. | Güllüce, M. | Agar, G. | Sengul, M. | Şahin, Fikrettin | Bariş, O.

Conference Object | 2009 | Acta Horticulturae826 , pp.59 - 64

In this study, antioxidant activities of four wild type Astragalus species namely, A. microcephalus, A. lagurus, A. macrocephalus and A. galegiformis have been investigated. Plant samples were collected from Erzurum (1700-2400 m, May 2006). Dried samples were extracted with methanol in a soxholet extractor (3 h) and antioxidant activities were tested. Two methods were employed for the activity tests. The first one is DPPH method which measures the free radical scavenging ability of the extract using 2,2-Diphenyl-1-picrylhydrazyl as stable free radical. Second test method Linoleic Acid Assay determines the relative antioxidant activi . . .ty (RAA %) and inhibition action of the extracts against oxidation is measured. The results showed that the extract obtained form the roots of A. macrocephalus exhibited the strongest antioxidant properties among the studied Astragalus species. Results will be discussed in details Daha fazlası Daha az

Kücükboyaci, N. | Güvenc, A. | Turan, N.N. | Aydin, A.

Article | 2012 | Turkish Journal of Pharmaceutical Sciences9 ( 1 ) , pp.93 - 100

The present study was carried out to investigate the antioxidant effects of aqueous extract of Raphanus raphanistrum L. (Brassicaceae) aerial parts by using various in vitro systems. The antioxidant activity of the plant was determined by the 2,2-diphenyl-l-picrylhydrazyl (DPPH) free radical scavenging test, flow injection analysis-luminol chemiluminescence (FIA-CL) and thiobarbituric acid (TBA) assays. To estimate the total phenolic content, the assay using Folin-Ciocalteu reagent was used. In addition, mineral composition of the raw plant was examined by atomic absorption spectroscopy. Raphanus raphanistrum aqueous extract was fou . . .nd to possess DPPH free radical scavenging activity (IC 50=8.78 mg/mL), inhibitory effect on H 2O 2-and HOCl-luminol chemiluminescence (-logIC 50=3.73 and 3.l×10 -2 mg/mL), and inhibitory activity toward lipid peroxidation (IC 50=63.33 µg/mL) compared to the references. The total phenolic content was 43.32 mg gallic acid/g extract. According to our results of mineral composition, the raw plant has lower amount of toxic elements (Pb, Cd and Al) than permissible level recommended by WHO. In addition, Ca level was found to be higher (16 mg/g) than daily intake of man. These observations suggest that Raphanus raphanistrum have a potential source of antioxidant and minerals of natural origin Daha fazlası Daha az

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

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

Celep, E. | Charehsaz, M. | Akyüz, S. | Acar, E.T. | Yeşilada, Erdem

Article | 2015 | Food Research International78 , pp.209 - 215

This study was designed to evaluate the effects of in vitro gastrointestinal simulation method on the antioxidant potentials and phenolic profile of some Turkish fruit wines and to compare the results with a Turkish red wine prepared from native grape varieties (Papazkarasi). For this purpose, blueberry, black mulberry and cherry wines were studied since they are widely consumed in Turkey. Papazkarasi wine was chosen due to the lack of studies regarding this type of wine. Antioxidant potentials of samples were measured with four different methods: DPPH radical-scavenging activity, H2O2-scavenging activity, cupric reducing capacity a . . .nd total antioxidant capacity assays. The phenolic profiles of samples were evaluated by the determination of total phenolic content and HPLC-DAD analysis of seven different molecules. The results of this study provided information not only the effect of gastrointestinal digestion on parameters mentioned above, but also the bioaccessibility about the phenolic compounds found in these four different wine samples. © 2015 Elsevier Ltd Daha fazlası Daha az