The alkaline comet assay as a method to investigate the DNA strand breaking effect of phenylpropanoids in mammalian cells

Abstract

Event Abstract Back to Event The alkaline comet assay as a method to investigate the DNA strand breaking effect of phenylpropanoids in mammalian cells Sabrina Haupenthal1, Sabrina Vallicotti2, Melanie Hemgesberg2 and Melanie Esselen1* 1 University of Münster, Institute of Food Chemistry, Germany 2 University of Kaiserslautern, Department of Food Chemistry and Toxicology, Germany The propenylic α-asarone (aA) and β-asarone (bA) as well as the allylic γ-asarone (gA) are naturally occurring constituents in several herbs and spices such as Acorus calamus (aA and bA) or Aniba hostmanniana (gA). Alcoholic beverages, teas, herbal medicine and cosmetics exhibit the most important route for human exposure [1]. aA and bA are classified as carcinogenic in rodents, whereas the data for gA is very limited so far [2]. For risk assessment further cellular studies about genotoxicity are required, so the question was addressed, whether the asarone isomers induce DNA strand breaks. Therefore, a modified alkaline comet assay to investigate DNA strand breaking effects of the asarone isomers in hamster lung fibroblasts (V79 cells and with human cytochrome P450 1A2 and human sulfotransferase 1C2 transfected V79 cells) was used. Furthermore, the DNA repair enzyme formamidopyrimidine DNA glycosylase (FPG) as a marker for oxidative DNA damage was also included in our test system. aA, bA as well as gA significantly induce DNA damage in V79 cells at concentrations > 10 µM. However, no enhanced DNA damage was observed after FPG-incubation of V79 cells. In contrast, in metabolic competent transfected V79 cells both propenylic asarone derivatives aA and bA significantly increase the amount of FPG-sensitive sites, whereas the allylic compound gA was not effective. This study assumes that an impact on the cellular redox status of the propenylic asarone isomers and their respective metabolites might contribute to their genotoxic properties. In conclusion, further in vitro studies on DNA damage and repair to elucidate the mechanism of genotoxicity and mutagenicity of these carcinogenic plant constituents are still under investigation.