Impact of xanthohumol (a prenylated flavonoid from hops) on DNA stability and other health-related biochemical parameters: Results of human intervention trials

Scope: Xanthohumol (XN) is a hop flavonoid found in beers and refreshment drinks. Results of in vitro and animal studies indicate that it causes beneficial health effects due to DNA protective, anti-inflammatory, antioxidant, and phytoestrogenic properties. Aim of the present study was to find out if XN causes alterations of health-related parameters in humans. Methods and results: The effects of the flavonoid were investigated in a randomized crossover intervention trial (n = 22) in which the participants consumed a XN drink (12 mg XN/P/day). We monitored alterations of the DNA stability in single cell gel electrophoresis assays in lymphocytes and of several health-related biomarkers. A decrease of oxidatively damaged purines and protection toward reactive oxygen species induced DNA damage was found after the consumption of the beverage; also the excretion of 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-guanosine in urine was reduced. The assumption that the flavonoid causes DNA protection was confirmed in a randomized follow-up study with pure XN (n = 10) with a parallel design. Other biochemical parameters reflecting the redox- and hormonal status and lipid- and glucose metabolism were not altered after the intervention. Conclusion: Taken together, our data indicate that low doses of XN protect humans against oxidative DNA damage. The effects of xanthohumol were investigated in a crossover intervention trial in which the participants consumed a drink containing 12 mg XN/P/day. Alterations of the DNA stability were monitored in single cell gel electrophoresis assays in lymphocytes. A decrease of oxidatively damaged purines and protection toward reactive oxygen species (ROS)-induced DNA damage was found after consumption of the beverage; furthermore, also urinary 8-oxo-7,8-dihydro-2'-deoxyguanosine and 8-oxo-guanosine were reduced.