Effect of Korean black raspberry (Rubus coreanus Miguel) fruit administration on DNA damage levels in smokers and screening biomarker investigation using 1H-NMR-based metabolic profiling

The effect of administration of Korean black raspberry (BR) to smokers was assessed by H-1 nuclear magnetic resonance (NMR) coupled with multivariate statistical analysis. In this study, to investigate the effect of BR on the level of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), biomarker for DNA damage, 38 male smokers between 20 and 30 years old were treated with BR or placebo for 4 weeks. After 4 weeks of administration, urinary level of 8-OHdG was measured, and the metabolic profiling of plasma samples of all volunteers were established using 1H NMR-based metabolomics techniques. The volunteers of BR administered group were divided into responder group (BR-R group) and nonresponder group (BR-NR group) based on the mean decrement of urinary 8-OHdG level of placebo group (12%). There was a clear separation among weeks 0 and 4 of seven volunteers at BR-R group in principal component analysis (PCA) derived score plots. The levels of 16 metabolites including amino acids, and organic acids changed significantly between weeks 0 and 4. Then the comparative metabolic profiling of the BR-R and BR-NR groups at week 0 was performed. There was also clear separation in PCA-derived score plot. The relative levels of glycine and trimethylamine N-oxide in plasma changed significantly between the two groups, indicating that these compounds could be used as screening biomarkers to predict the 8-OHdG modulating activity of BR in smokers. (C) 2012 Elsevier Ltd. All rights reserved.