Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection
Permanent URI for this collectionhttps://hdl.handle.net/11147/7148
Browse
2 results
Search Results
Now showing 1 - 2 of 2
Conference Object Citation - Scopus: 4Trans-resveratrol’ün Kitosan Mikroküreler İçerisindeki Kararlılığı(Institute of Electrical and Electronics Engineers Inc., 2009) Altıok, Duygu; Altıok, Evren; Bayraktar, Oğuz; Tıhmınlıoğlu, Fundatrans-Resveratrol, (3,5,4?-trihydroxy-trans-stilbene), a phenolic compound present in some plant species, have been shown to posses antioxidative, anticarcinogenic and antitumour properties. However, under UV light, it turns into -cis form and looses its bioactivity.This study aims to increase the stability of trans-resveratrol by loading it into chitosan microspheres. Within this context, the trans-resveratrol loaded chitosan microspheres was produced by spray drying and then the resultant microspheres were characterized. The particle size and the surface morphology of resultant microspheres were investigated by scanning electron microscope (SEM) and the thermal properties were determined by thermogravimetry analyser(TGA). The stability of free and that of inside the microspheres was determined by high performance liquid chromatography (HPLC). It was found that the stability of trans-resveratrol incorporated into chitosan microspheres kept constant. ©2009 IEEE.Article Citation - WoS: 42Citation - Scopus: 60Pistacia Terebinthus Extract: as a Potential Antioxidant, Antimicrobial and Possible Ss-Glucuronidase Inhibitor(Elsevier Ltd., 2010) Demirbüker Kavak, Dilek; Altıok, Evren; Bayraktar, Oğuz; Ülkü, SemraIn this study, inhibition of Escherichia coli glucuronidase (GUS) by a plant extract of Pistacia terebinthus was investigated. P. terebinthus (from Karaburun region in Turkey) leaf extract exhibits various bioactivities, such as antioxidant, antimicrobial and cytotoxic property because of its flavonoid, phenolic and alkaloid contents. HPLC analyses were performed to evaluate the composition of the extract and main flavonoid compounds such as luteolin, luteolin-7-glucoside and apigenin-7-glucoside were detected in extract. GUS activity and kinetic data of the GUS were obtained by measuring rate of production of resulting fluorescent 4-methylumbelliferone (4-MU) and phenolphthalein fluorometrically and spectrophotometrically, respectively. Plant leaves showed higher antioxidant capacity as 85 TEAC (trolox equivalent antioxidant capacity) value and higher antimicrobial activity towards Staphylococcus aureus. 92.4% GUS enzyme inhibition was achieved with 8.3 μg ml-1 crude extract concentration, where IC50 value was found as 2.1 (±0.2) μg ml-1. Kinetic studies by nonlinear regression revealed that inhibition type caused by plant extract was mixed type (noncompetitive and competitive together). Km and Vmax values were 96.94 ± 9.68 nM and 7.81 ± 0.16 nmol min-1 mg-1, respectively. Inhibition constant (αKi) was found as 7.00 ± 0.93 nM having α value 2.17 ± 0.93. Our results may provide useful information regarding the inhibition of microbial GUS activity, preventing deglucuronidation and reducing possible cancer risk by bioactive P. terebinthus crude extract. © 2010 Elsevier B.V. All rights reserved.