Epigallocatechin-3-gallate reduces DNA damage induced by benzo[a]pyrene diol epoxide and cigarette smoke condensate in human mucosa tissue cultures

Abstract

Although epidemiological studies indicate cancer preventive effects of diets rich in fruit and vegetables, large clinical intervention studies conducted to evaluate dietary supplementation with micronutrients, mostly vitamins, showed disappointing results in large parts. In contrast, there is encouraging epidemiologic data indicating great chemopreventive potential of a large group of phytochemicals, namely polyphenols. This study shows the DNA protective effect epigallocatechin-3-gallate, a tea catechin, and one of the best-studied substances within this group, on carcinogen-induced DNA fragmentation in upper aerodigestive tract cells. Cell cultures from fresh oropharyngeal mucosa biopsies were preincubated with epigallocatechin-3-gallate in different concentrations before DNA damage was introduced with the metabolically activated carcinogen benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide or cigarette smoke condensate. Effects on resulting DNA fragmentation were measured using the alkaline single-cell microgel electrophoresis (comet assay). Epigallocatechin-3-gallate significantly reduced benzo[a]pyrene-7,8-dihydrodiol-9,10-epoxide-induced DNA damage by up to 51% (P<0.001). Fragmentation induced by cigarette smoke condensate could be lowered by 47% (P<0.001). Data suggest a cancer preventive potential of epigallocatechin-3-gallate as demonstrated on a subcellular level. An additional mechanism of tea catechin action is revealed by using a primary mucosa culture model.

Curcumin and Other Polyphenolic Compounds in Head and Neck Cancer Chemoprevention

“…DNA damage was induced by CSC during an 18-hour-incubation period. Here, DNA damage was decreased by 28% after 1 and by 47% after 4 incubations [80]. Similar results were seen when cultures were exposed to tannins during 30 minutes on 3 days.…”

“…Compared to the other polyphenols tested in our laboratory, curcumin was most effective preventing tobacco-related DNA damage. All compounds reduced genotoxic effects of B(a)p or CSC in a dose-dependent manner [80, 81]. …”

Structure of flavonoids influences the degree inhibition of Benzo(a)pyrene – induced DNA damage and micronuclei in HepG2 cells

“…These compounds are formed from natural and man-made INHIBITION OF GENOTOXICITY OF BENZO(A)PYRENE BY FLAVONOIDS sources, but the man-made B(a)P is quantitatively the most significant [9]. B(a)P has been implicated in the evolution of various cancers of lung and colon; people are exposed to B(a)P through cigarette smoking [10], occupational exposure [11], and intake of broiled or smoked food [12]. B(a)P has been shown to induce gene mutations, chromosomal aberrations and other types of genotoxic effects both in vitro and in vivo [13].…”

The Use of Single-Cell Comet Assay on Oral Cells: A Critical Review

“…Finally, some chemopreventive studies against genotoxicity induced in oral cells were found. The most significant were those related to black tea and tobacco smoke (37); epigallocatechin-3-gallate and smoke (38); histone acetylase inhibitor for therapeutics (39); and Pteridium aquilinum extract against oral cancer cells (40). To the best of our knowledge, only two articles investigated the genotoxicity induced by cannabimimetic drug (41) and radiation (42) in oral cells by comet assay.…”