Effect of Korean black raspberry (Rubus coreanus Miquel) 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 1H 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.

► Korean black raspberry (BR) had a beneficial effect on DNA damage level in smokers. ► BR-administered group was divided into responder and nonresponder groups. ► Glycine and trimethylamine N-oxide suggested as biomarkers to predict BR-responders.