Please use this identifier to cite or link to this item: http://hdl.handle.net/10397/64019
Title: Redox-linked effects of green tea on DNA damage and repair, and influence of microsattelite polymorphism in HMOX-1 : results of a human intervention trial
Authors: Choi, SWV
Yeung, TFA
Collins, R
Benzie, IFF 
Issue Date: 2014
Publisher: Oxford University Press
Source: Mutagenesis, 2014, v. 30, no. 1, p. 129-137 How to cite?
Journal: Mutagenesis 
Abstract: Green tea has many reported health benefits, including genoprotective and antioxidant effects, but green tea has pro-oxidant activity in vitro. A tea-induced pro-oxidant shift that triggers cytoprotective adaptations has been postulated, but human data are lacking. We investigated effects on oxidation-induced DNA damage and redox-linked cytoprotective factors, including 8-oxoguanine glycosylase (hOGG1) and heme oxygenase 1 (HMOX-1) in lymphocytes in a randomised, placebo-controlled, cross-over supplementation trial. hOGG1 catalyses the first step in base excision repair; increased HMOX-1 is a sign of cytoprotective response to pro-oxidant change. The influence of microsatellite polymorphisms in the HMOX-1 promoter region was also explored. Higher numbers of GT repeats [GT(n)] in this region reportedly diminish response to pro-oxidant change. Green tea [2×150ml of 1% w/v tea/day (or water as control)] was taken for 12 weeks by 43 Type 2 diabetes subjects {20 with short [S/S; GT(n) < 25] and 23 with long [L/L; GT(n) ≥ 25]}. Fasting venous blood was collected before and after each treatment. The formamidopyrimidine DNA glycosylase-assisted comet assay was used to measure DNA damage in lymphocytes. For measuring hOGG1 activity, we used photo-damaged HeLa cells incubated with lymphocyte extracts from test subjects, in combination with the comet assay. Lymphocyte HMOX-1 and hOGG1 protein concentrations and expression (mRNA) of redox-sensitive genes, including HMOX-1 and hOGG1, were also investigated. Results showed significantly (P < 0.01) lower (~15%) DNA damage, higher (~50%) hOGG1 activity and higher (~40%) HMOX-1 protein concentration after tea. No changes in mRNA expression were seen. Baseline HMOX-1 protein and hOGG1 activity were higher (P < 0.05) in the S/S group, but tea-associated responses were similar in both GT(n) groups. Green tea is clearly associated with lowered DNA damage, increased hOGG1 activity and higher HMOX-1 protein levels. Further study is needed to confirm a cause and effect relationship and to establish if these effects are mediated by post-translational changes in proteins or by increased gene expression.
URI: http://hdl.handle.net/10397/64019
ISSN: 0267-8357 (print)
1464-3804 (online)
DOI: 10.1093/mutage/geu022
Appears in Collections:Journal/Magazine Article

Access
View full-text via PolyU eLinks SFX Query
Show full item record

WEB OF SCIENCETM
Citations

3
Last Week
0
Last month
Citations as of Aug 14, 2017

Page view(s)

24
Last Week
0
Last month
Checked on Aug 20, 2017

Google ScholarTM

Check

Altmetric



Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.