Modulation of tea and tea polyphenols on benzo(a)pyrene-induced DNA damage in Chang liver cells

Gow Chin Yen, Jyh Woei Ju, Chi H. Wu

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The protective effects of three tea extracts (green tea, GTE; oolong tea, OTE; and black tea, BTE) and five tea polyphenols (epicatechin, EC; epicatechin gallate, ECG; epigallocatechin, EGC; epigallocatechin gallate, EGCG; and theaflavins, THFs) on benzo[a]pyrene (B[a]P)-induced DNA damage in Chang liver cells were evaluated using the comet assay. B[a]P-induced DNA damage in Chang liver cells was significantly (p <0.05) inhibited by GTE and OTE at a concentration of 10 μg/ml and by BTE at 25 μg/ml. At a concentration of 100 μg/ml, the % tail DNA was reduced from 33% (B[a]P treated only) to 10, 9,13%, by GTE, OTE and BTE, respectively. EC and ECG did not cause DNA damage in cells according to the results of the comet assay; however, EGC, EGCG and theaflavins caused DNA damage in cells at a concentration of 100 μM. The results indicated that EC and ECG had protective effects against B[a]P-induced DNA damage in cells at a concentration of 10-100 μM. Although EGC, EGCG and the theaflavins caused DNA damage at a high concentration, but they had protective effects against B[a]P-induced DNA damage in cells at a low concentration of 10-50 μM. The results also showed that the DNA damage in cells induced by EGC, EGCG, and the theaflavins was due to the generation of superoxide during incubation with cells at a higher concentration. Therefore, tea catechins and THFs play an important role in enabling tea extracts to inhibit DNA damage in Chang liver cells.

Original languageEnglish
Pages (from-to)193-200
Number of pages8
JournalFree Radical Research
Volume38
Issue number2
DOIs
Publication statusPublished - Feb 2004
Externally publishedYes

Keywords

  • Chang liver cells
  • Comet assay
  • DNA damage
  • Tea
  • Tea polynenols

ASJC Scopus subject areas

  • Biochemistry

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