Antigenotoxic potential of plant monoterpenes linalool, myrcene and eucalyptol against IQ- and PhIP- induced DNA damage

Abstract

© 2016 Institute of Botany and Botanical Garden Jevremovac, Belgrade. Nutrition is recognised as one of the major factors that can influence the development ofcancer. Heterocyclic amines formed during the cooking of meat are genotoxic carcinogens andconsumption of meat positively correlates with certain types of human cancer. On the other hand,it has been reported that many plant components reduce the genotoxic activities of carcinogens,including HCAs. In this study we investigated the antigenotoxic potential of the monoterpeneslinalool, myrcene and eucalyptol against two food-borne carcinogens: 2-amino-1-methyl-6-phenylimidazo[4-5-b]pyridine (PhIP) and 2-amino-3-methylimidazo[4,5-f]-quinoline (IQ). Thestudy was performed by the comet assay method in metabolically active HepG2 human hepatomacells. In addition, the lipid peroxidation TBA assay was used to determine the anti-oxidative potentialof these monoterpenes. To evaluate the antigenotoxic potential, cells were treated simultaneouslywith 0.01, 0.1 or 1 μg/mL of monoterpenes and either 90 μmol/LPhIP or 0.75 mmol/L IQ. The DNAdamage induced by PhIP was reduced significantly (by 40-63%) by each of the three monoterpenes,while inhibition of IQ-induced DNA damage was less efficient (12-26% reduction) and limited tomyrcene and eucalyptol. Lipid peroxidation was significantly inhibited by linalool and myrcene,with IC50 values of approximately 30 μg/mL and 300 μg/mL, respectively. Eucalyptol showed onlyweak antioxidant activity (15% inhibition at 500 μg/mL). Taking into account the fact that reactiveoxygen species (ROS) are formed during metabolic processing of PhIP, we assume that moreefficient protection against PhIP-induced DNA damage was probably due to antioxidative activityof the monoterpenes or their metabolites, but the ability to interfere with metabolic activation ofPhIP and IQ could also be involved.