Antioxidant effects of Camellia sinensis L. Extract in patients with type 2 diabetes

Funding Information: The authors would like to thank the Department of Analytical and Toxicological Chemistry of the Lithuanian University of Health Sciences for using HPLC. This research is a part of an international “Eureka” E! 3695 project “Creation of the methodology for effects of natural antioxidants on the development of diabetes mellitus complications” (“Antioksdiabet”). This project has been established with financial support from the European Social Fund Agency, Lithuania , in the “Human Resource Development Action Program”, project Number VP1-3.1-SMM-06-V-01-003 . We would also like to thank the Laboratory of Biochemistry, Riga Stradins University, Latvia for performing biochemical tests of blood plasma and the residents of the Endocrinological Clinic, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Lithuania for their help. The provision of ECs and placebo capsules from the joint-stock company Sanitas is also appreciated. Publisher Copyright: © 2014, Food and Drug Administration, Taiwan. Published by Elsevier Taiwan LLC. All rights reserved.The prevalence of diabetes mellitus (DM) has dramatically increased in the past decade. Furthermore, increasing evidence from research shows that oxidative stress (OS) plays a crucial role in the pathogenesis of diabetes and in its complications. A search for ways to reduce oxidative damage has become the focus of interest for the majority of scientists. In this study, we determined the radical scavenging activity of single green tea constituents by using an on-line high performance liquid chromatography (HPLC)-2,2-diphenyl-1-picrylhydrazyl (DPPH) method and evaluated the antioxidant effects on type 2 diabetic patients by performing a double-blind, placebo-controlled study. Epigallocatechin gallate was identified as the most potent antioxidant, contributing approximately 50% of the total antioxidant capacity of green tea extract. We also found a statistically significant decrement of lipid peroxidation markers in patients treated with green tea extract after 9 months or after 18 months of follow-up. Overall, these findings are attractive for diabetic patients, helping them to keep a high level of performance and well-being, which ultimately may delay the time of disability and reduce mortality.Peer reviewe