Yazar "Emen, Sevil" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • [ X ]
    Öğe
    Antioxidant activities of ethanol extracts of Hypericum triquetrifolium and Hypericum scabroides
    (Taylor & Francis Ltd, 2008) Kizil, Goeksel; Kizil, Murat; Yavuz, Murat; Emen, Sevil; Hakimoglu, Fidan
    The antioxidative potential of ethanol extracts of Hypericum triquetrifolium Turra (Hypericaceae) and Hypericum scabroides Robson Poulter (Hypericaceae) were investigated for the first time using 1,1-diphenyl-2-picrylhydrazyl (DPPH), metal chelating, reducing power, hydroxyl radical, total antioxidant activity, and lipid peroxidation inhibition assays. Both extracts tested were found to be highly active in the DPPH radical scavenging assay. The IC50 values of H. triquetrifolium (HT) and H. scabroides (HS) in the DPPH radical scavenging assay were 39.0 and 33.8 mu g/mL, respectively. The amounts of total phenolic compounds were also determined, and total phenolic content of 1 mg H. triquetrifolium and H. scabroides ethanol extracts were equivalent to 267 and 333 mu g gallic acid. Metal chelating ability was found to be low compared with EDTA. Both ethanol extracts of Hypericum species exhibited a high reducing power, suggesting that extracts had strong electron-donating capacity. The degradation of deoxyribose by hydroxyl radicals was shown to be inhibited by Hypericum extracts, acting mainly by scavenging hydroxyl radicals rather than as chelators of iron ions. Total antioxidant activity of ethanol extracts of HT and HS were tested by using ferric thiocyanate (FTC) and thiobarbituric acid (TBA) methods. Antioxidative activities of both extracts were found to be comparable with vitamin E. Moreover, both extracts showed notable capacity to suppress Fe2+-induced lipid peroxidation in rat brain homogenate. The results obtained in the current study indicate that ethanol extracts of HS and HT are a potential source of natural antioxidants.
  • Küçük Resim
    Öğe
    Cyclotrichium niveum bitkisinin farklı polariteye sahip çözücüler ile hazırlanan ekstraktlarının antioksidant ve DNA'yı serbest radikallerden koruma etkilerinin araştırılması
    (2017) Emen, Sevil; Kızıl, Murat
    Cyclotrichium niveum, labiate ailesinin bir üyesidir. Türkiye'de baharat olarakyaygın bir sekilde kullanılmaktadır. Bu bitkinin birçok faydasının oldugu öne sürülse debu konuyla ilgili az sayıda bilimsel çalısma bulunmaktadır. Bu tezde C.niveumbitkisinin tüm kısımlarının (dal+yaprak+çiçek) metanol, etilasetat ve n-butanolekstraktlarının antioksidant aktiviteleri arastırıldı. Toplam fenolik bilesen miktarı Folin-Ciocalteu reaktifi yöntemiyle belirlendi. Metanol, etilasetat ve n-butanol ekstraktlarının1 mg'nın içerdigi toplam fenolik bilesen miktarı sırasıyla 200.9±35.0, 192.4±42.0,252.0±42.0 ?g gallik asite esdeger olarak bulundu.C.niveum bitkisinin metanol, etilasetat ve n-butanol ekstraktlarının antioksidantaktiviteleri in vitro sistemde farklı antioksidant testler kullanılarak arastırıldı. Sıçanbeyni homojenatında lipit peroksidasyonunu önleme aktivitesine bakıldı ve 1,1-difenil-2-pikril-hidrazil (DPPH) radikalini, hidroksi radikalini söndürme, indirgeme gücü vemetal selatlama aktiviteleri incelendi. C.niveum metanol, etilasetat ve n-butanolekstraktları FeCl2-H2O2 sisteminde güçlü lipit peroksidasyonunu önleme aktivitesi veayrıca deoksiriboz oksidasyonunda konsantrasyona baglı olmayan etki gösterdigi tespitedildi. C.niveum ekstraktları aynı zamanda DPPH radikal sisteminde dikkat çekiciantioksidant aktivite sergilediler. C.niveum metanol, etilasetat ve n-butanolekstraktlarının DPPH radikalini söndürme aktiviteleri 500 ?g/mL konsantrasyondasırasıyla % 90.3±1.2, 91.4±0.7, 91.7±0.7 bulundu. Diger bir antioksidant test olarakmetal selatlama aktivitesi incelendi ve bitki ekstraktlarının Fe2+ iyonunu tutmakapasitesinin EDTA' dan daha düsük oldugu bulundu. C. niveum ekstraktlarının aynızamanda plazmid DNA'yı hidroksi radikallerinin neden oldugu kesimine karsıkorudugu gözlendi. Bu sonuçlar, bize C. niveum bitkisinin yüksek antioksidantaktiviteye sahip oldugunu göstermektedir.Sonraki çalısmalar, metanol, etilasetat ve n-butanol ekstraktlarının biyoaktifbilesenlerinin aydınlatılması ve karakterizasyonuna yönelik olmalıdır. C. niveum'unantioksidant aktivitesinde rol alan fenolik bilesenlerin tek olarak mı yoksa sinerjikolarak mı etki gösterdikleri arastırılmalıdır.Anahtar Kelimeler: Cyclotrichium niveum, Antioksidant aktivite, DNA hasarı, Serbestradikaller
  • [ X ]
    Öğe
    DNA damage protecting activity and in vitro antioxidant potential of the methanol extract of Cyclotrichium niveum
    (Taylor & Francis Ltd, 2009) Emen, Sevil; Ceken, Bircan; Kizil, Goksel; Kizil, Murat
    Cyclotrichium niveum (Boiss.) Manden. & Scheng., a herb of the Labiate family, has been widely used as a flavoring agent in Turkey; it was examined for its antioxidant potential and DNA damage protecting activity. The antioxidant activity of C niveum aerial parts (stems, leaves, and flowers) was determined from the methanol extract. The antioxidant potency of methanol extract of C niveum was investigated employing various established in vitro systems, such as lipid peroxidation in rat brain homogenate, 1,1-diphenyl-2-picrylhydrazyl (DPPH), hyrdoxyl radical scavenging, reducing power, iron chelation, and inhibitory effect on protein oxidation. The methanol extract of C niveum was able to reduce the stable free radical DPPH with an IC50 of 78.15 mu g/mL. The metal chelating ability was found to be low compare with EDTA. Methanol extract of C. niveum aerial parts showed strong inhibitory activity toward lipid peroxidation of rat brain homogenate induced by the FeCl2-H2O2 system. Furthermore, C. niveum extract exhibited a strong concentration-dependent inhibition of deoxyribose oxidation. The effect on DNA cleavage induced by H2O2 UV-photolysis was also investigated. It showed a concentration-dependent free radical scavenging capacity and protective effect on DNA cleavage. In addition, the oxidative damage of bovine serum albumin (BSA), induced by hydroxyl radical in an acellular system, was inhibited by 10-1000 mu g/mL of methanol extract of C. niveum. The total phenolic content of C niveum was detected in methanol as 200.9 mu g gallic acid/mg extract. These results clearly demonstrated that C niveum extract possesses a marked antioxidant activity and it is a potential source of natural antioxidants.
  • [ X ]
    Öğe
    In vitro inhibition of advanced glycation end product formation by ethanol extract of milk thistle (Silybum marianum L.) seed
    (Elsevier, 2022) Inceoren, Nesrin; Emen, Sevil; Toptanci, Bircan Ceken; Kizil, Goksel; Kizil, Murat
    Glycation of proteins by reducing sugars produces toxic and immunogenic compounds called advanced gly-cation end products (AGEs). AGEs plays important role in the progression of typical diabetes complications. Silybum marianum L. contains powerful antioxidants that quench free radicals, which are unstable and reac-tive compounds that damage DNA and cellular structures. This study aimed to evaluate the antioxidant activ-ities and the inhibitory effects of ethanol:water (1:1) extract of the Silybum marianum seed (SlyE) and silymarin (Sly) on fructose mediated protein glycation and AGE formation. The total amount of silymarin in SlyE was found to be 2.59 mg/gDW by HPLC. The composition of phenolic in the extract was found to be 262.70 mg gallic acid (GAE)/mg extract. The composition of flavonoids in the extract was found to be 10.50 mg quercetin (QUE)/mg extract. The seed exhibited ABTS radical cation decolourization inhibition with 70.4% at 300 mg concentration. Ferric reducing power of the extract was also evaluated. The SlyE and Sly also demonstrated strong inhibitory effects on the production AGEs in bovine serum albumin (BSA)/fructose model. SlyE and Sly has a significant effect in preventing oxidative protein damage, including the effect on the formation of fructosamines, a-dicarbonyls and protein carbonyl content (PCC). SlyE and Sly were able to prevent the glycoxidative damage of BSA. It can be concluded that the SlyE has antiglycating potential as well as antioxidant properties. (C) 2022 SAAB. Published by Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Solvent-free synthesis of nitrilotriacetamide and diketopiperazines from nitrilotriacetic acid under microwave irradiation and their antimicrobial activity
    (Taylor & Francis Inc, 2007) Oeztuerk, Guelsen; Guemguem, Bahattin; Kizil, Murat; Emen, Sevil
    Efficient synthesis of dioxopiperazines-diketopiperzines (DKPs)- and amide from nitrilotriacetic acid (NTA) using microwave irradiation and classical heating were described. All compounds were characterized using H-1 NMR, C-13 NMR and elemental analysis. Antimicrobial effects of these compounds are also investigated. All tested compounds showed moderate antimicrobial activity.