Journal of Environmental Pathology, Toxicology and Oncology

ISSN for PRINT: 0731-8898

For Online Access

Best Paper Award Selection - Editorial Board Site

2005, Volume24

Issue 2

76 pages

DOI: 10.1615/JEnvPathToxOncol.v24.i2

Issue price - $160.00

Rajesh Krishnan
Tobacco Carcinogenesis Group, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, India

Girish B. Maru
Tobacco Carcinogenesis Group, Advanced Centre for Treatment, Research and Education in Cancer (ACTREC), Tata Memorial Centre, Kharghar, Navi Mumbai, India

The biological activities and chemopreventive properties of green tea polyphenols have been demonstrated, while similar information regarding newly formed major polymeric polyphenols in black tea are not available. Cancer chemoprevention may be achieved by the inhibition of any stage of carcinogenesis. In the present study, we investigated the anti-initiating effects of five polymeric black tea polyphenol (PBP) fractions, by determining their effects on the formation of [³H]-B(a)P-derived DNA adducts as well as the activity of cytochrome P-450 isozymes CYP 1A1 and 1A2 in vitro employing rat liver microsomes. PBP 1-3 inhibited both the microsome catalyzed [³H]-B(a)P-derived DNA adduct formation as well as the activity of CYP 1A1 and 1A2 as assessed by the decreased formation of resorufin from the respective substrates. Further investigation revealed that topical pretreatment(s) of mice with PBP 1-5 (200 μg/day × 4) resulted in a significant decrease in the levels of single topical B(a)P (1 mg/mouse) - induced DNA adducts in epidermal DNA determined by employing ³²P-post labeling analysis. Overall, our results suggest that black tea-derived PBPs have one of the chemopreventive properties shown by monomeric green tea polyphenols.

DOI: 10.1615/JEnvPathToxOncol.v24.i2.20 Download article, 79-90 pages

Article price - $35.00

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