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    Enzymatic Synthesis of Uracil Glucuronide, Labeling with (125)/I-131, and In Vitro Evaluation on Adenocarcinoma Cells
    (Mary Ann Liebert, Inc, 2010) Medine, Ilker Emin; Unak, Perihan; Sakarya, Serhan; Toksoz, Feriha
    Human UDP-glucuronosyltransferases (UGTs) are a family of membrane-bound enzymes of the endoplasmic reticulum. They catalyze the glucuronidation of various endogenous and exogenous compounds, converting them into more polar glucuronides. In this study, uracil glucuronide was enzymatically synthesized using a UGT-rich microsome preparate, which was separated from Hutu-80 cells. Two different glucuronide derivatives were obtained, with a total reaction yield of 22.95% +/- 2.4% (n = 4). The glucuronide ligands were defined as uracil-n-glucuronide (UNG) and uracil-o-glucuronide (UOG). These were then analyzed by high-performance liquid chromatography-mass spectrometry and labeled with I-125 and I-131, separately. The radiolabeled (125)/I-131-UNG and (125)/I-131-UOG presented good incorporation ratios for Hutu-80, Caco-2, Detroit 562, and ACBRI 519 cells. The incorporation ratios of (125)/I-131-UOG were higher than those of (125)/I-131-UNG and of other labeled components for all cell types, and were also statistically significant compared to the values of (125)/I-131-UNG for primary human intestinal epithelial cells (ACBRI 519) and human intestinal adenocarcinoma cells. Cell incorporation rates of n-glucuronides and o-glucuronides were higher compared to uracil, with o-glucuronides being more selective. The results suggest that both I-125- and I-131-labeled glucuronides can be used in imaging and therapy, and further research should be done in preclinical stages.
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    Radiolabeling of EGCG with I-131 and biodistribution in rats
    (Birkhauser Boston Inc, 2012) Toksoz, Feriha; Demir, Ilknur; Bayrak, Elif; Kocagozoglu, Gamze; Onursal, Mehmet; Karademir, Gulgun; Lambrecht, Fatma Yurt
    Epigallocatechin gallate (EGCG), is the most abundant and widely studied catechin in green tea (Camellia sinensis Theaceae). The inhibitory effects of EGCG and green tea extract on carcinogenesis in various organs in rodents have now been demonstrated over the past decade. The aim of study was to label EGCG with I-131, to determinate its structure and to evaluate its biodistribution in Wistar rats. Radiolabeling was carried out by direct electrophilic iodination method (iodogen) and yield was determined by radio thin layer chromatography (RTLC). Radiolabelling yield is determined as 89 +/- A 1.0%. Besides, determination of structure of iodinated molecule, serum stability, and partition coefficient experiments was performed. The structure analysis of synthesized cold I-127-EGCG complex was assessed with LC-MS-MS and H-1-NMR. H-1-NMR and LC-MS-MS results of iodinated EGCG (I-127-EGCG) show that oxidize iodine reacts electrophilic with aromatic ring. Serum stability results showed that in vitro stability of I-131-EGCG was quite high. It is observed that labeling percentage decreased 83 +/- A 2% at 24th, Partition coefficient results show that the partition coefficient of EGCG was calculated as theoretical partition coefficient = 2.04 +/- A 0.42 and the experimental partition coefficient of I-131-EGCG was found as 1.46 +/- A 0.2. The biodistribution data shown that the maximum uptake of the radioiodinated EGCG was seen in lung and pancreas at 30 min. The blocking assay results indicated that the uptake of I-131-EGCG in lung was not significantly change (0.25, 0.23, and 0.22%ID/g at 30, 60, and 150 min, respectively). Biodistribution data showed no significant uptake in a specific organ of the rat. Hence radiolabeled EGCG is seen in some organs (lung, liver, pancreas, kidney, etc.).