Mutagenic Activity of Tea Flavonoid ( — )-Epigallocatechin in Bacterial and Mammalian Cells

摘要

Animal studies have revealed that tea flavonoids, knownas catechins, have the potential to prevent cancer. We in-vestigated the genotoxicity of the 4 main green tea cate-chins, namely, ( —)-epigallocatechin gallate (EGCG),( —)-epigallocatechin (EGC), ( — )-epicatechin gallate (ECG),and ( — )-epicatechin (EC), using the comet assay inChinese hamster CHL/IU cells. By measuring the percentof DNA in the comet tail, we concluded that EC, ECG, andEGCG did not induce biologically significant DNA damage.In contrast, EGC induced strong DNA damage at concen-trations of 100μM or higher. We further examined thegenotoxic ability of EGC by the reverse mutation assay andthe in vitro chromosome aberration test. The reverse muta-tion assay, revealed a maximum of 1.8-fold increase in themean number of revertant colonies at 5000μg/plate ofEGC as compared to the number of colonies in the solventcontrol in Escherichia coli WP2uvrA/pKM101. EGC causedchromosome aberrations at low frequency in CHL/IU cellsat a concentration of 200μM. We concluded that EGC wasweakly mutagenic in bacterial and mammalian cells.