Effects of (−)-epigallocatechin gallate (EGCG) on DNA strand breaks as evaluated by single-cell gel electrophoresis (SCG) in human lymphocytes

Abstract

(-)-Epigallocatechin gallate (EGCG), a catechin polyphenol component, is the main ingredient of green tea extract. Although the anti-carcinogenic and cancer inhibitory effects of EGCG have been widely reported, its genotoxicity is not clear and seldom reported. In this study, we examined the effects of EGCG on DNA strand breaks in the isolated lymphocytes and whole blood lymphocytes obtained from two smoking subjects and a nonsmoking healthy subject using a single cell gel electrophoresis (SCG) assay. The results showed that after 2 hrs of treating the isolated lymphocytes from the smokers, EGCG induced a significant, increase in DNA strand breaks at concentrations from 2.5×10(-5) M to 2.0×10(-4) M, while after 2 hrs of treating the whole blood obtained from the same smokers, EGCG suppressed the DNA strand breaks in the lymphocytes at concentrations of 1.0×10(-4) M and 2.0×10(-4) M. A similar suppressive result was also shown in the whole blood lymphocytes from the nonsmoker at nearly the same concentrations, while at concentrations of 1.0×10(-3) M or 2.0×10(-3) M, EGCG induced a significant increase in DNA strand breaks in the whole blood lymphocytes from the nonsmoker. This result suggests that EGCG is not only inhibitory against DNA strand breaks in whole blood, but also genotoxic to the isolated or whole blood lymphocytes at high concentrations. Thus, more research is needed to comprehensively assess the effects of EGCG on genetic materials.

Protective effects of black tea extract against oxidative DNA damage in human lymphocytes

“…Several studies have demonstrated protective effects of epigallocatechin-3-gallate (EGCG), the predominant polyphenolic component of green tea, on the generation of DNA strand breaks in human lymphocytes (25)(26)(27). Therefore, the present study aimed to investigate the effects of BTE on DNA oxidative damage on human healthy lymphocytes, using a comet assay.…”

Computational DNA binding studies of (–)-epigallocatechin-3-gallate

“…Cooperative effect was observed when the anti-cancer, DNA binding compound bleomycin was used in conjunction with EGCG, showing a potentiated anti-proliferative effect in pancreatic cancer cells (Bimonte et al, 2015). Additionally, interaction of EGCG in single-strand DNA chains showed increased nuclease activity in whole blood and isolated lymphocytes cells (Yuquan, Takeshita, & Morimoto, 2001). Using surface plasmon resonance assays and cold spray ionization-mass spectrometry, Fujiki and collaborators found that EGCG binds to DNA and RNA polymers between 1:1 and 3:1 stoichiometry (Kuzuhara, Sei, Yamaguchi, Suganuma, & Fujiki, 2006).…”