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Effects of Green Tea Catechin on Polymorphonuclear Leukocyte 5'-Lipoxygenase Activity, Leukotriene B4 Synthesis, and Renal Damage in Diabetic Rats
Jeong-Hwa Choia, Young-Mi Chaib, Gil-Jae Jooc, In-Koo Rheec, In-Seon Leed, Kwan-Ryu Kime, Myung-Sook Choif, Soon-Jae Rheeb

Annals of Nutrition & Metabolism 2004;48:151-155 (DOI: 10.1159/000078378)

aDivision of Food Science, Jinju International University, Gyeongnam;
bDepartment of Food Science and Nutrition, Catholic University of Daegu, Gyeongbuk;
cDepartment of Agricultural Chemistry, Kyungpook National University, Daegu;
dCenter for Traditional Microorganism Resources, Keimyung University, Daegu;
eDepartment of Food Engineering, Ansan Technical College, Gyeonggi, and
fDepartment of Food Science and Nutrition, Kyungpook National University, Daegu, Korea

Abstract

The purpose of this study was to investigate the effects of green tea catechin on polymorphonuclear leukocyte 5'-lipoxygenase activity, leukotriene B4 synthesis, and renal damage in diabetic rats. Male Sprague-Dawley rats weighing 100 ± 10 g were randomly assigned to 1 normal group and 3 diabetic groups given a catechin-free diet (DM-0C group), 0.25% catechin diet (DM-0.25C group), or 0.5% catechin diet (DM-0.5C group), respectively. 5'-Lipoxygenase activity in the polymorphonuclear leukocytes significantly increased by 54% in the DM-0C group compared to the normal group, while the level in the DM-0.5C group remained the same as in the normal group. The leukotriene B4 content in the polymorphonuclear leukocytes increased 55% in the DM-0C group compared to the normal group, whereas the DM-0.25C and DM-0.5C groups exhibited the same level as the normal group. The superoxide radical content in the kidney microsomes increased 116% in the DM-0C group when compared to the normal group, yet decreased 29% in the DM-0.25C group and 50% in the DM-0.5C group compared to DM-0C group. The lipofuscin content was 197 and 136% higher in the DM-0C and DM-025C groups, respectively, than in the normal group, whereas the DM-0.5C group exhibited the same content as in the normal group. The carbonyl value increased 118% in the DM-0C group compared to the normal group, and the DM-0.25C and DM-0.5C groups were not significantly different from the DM-0C group. Accordingly, these results indicate that dietary catechin inhibited the generation of superoxide radicals, oxidized protein, and lipid peroxide in the kidney of streptozotocin-induced diabetic rats. Furthermore, green tea catechin supplementation in diabetic rats also appeared to inhibit the production of leukotriene B4 based on regulating the activity of 5'-lipoxygenase, thereby potentially reducing renal oxidative damage and inflammatory reactions.

Author Contacts

Soon-Jae Rhee, PhD
Department of Food Science and Nutrition, Catholic University of Daegu
Gyeongsan-si, Gyeongbuk, 712-702 (Korea)
Tel. +82 53 850 3523, Fax +82 53 850 3504
E-Mail sjrhee@cu.ac.kr

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