TY - JOUR
T1 - Prevention of photocarcinogenesis by topical administration of pure epigallocatechin gallate isolated from green tea
AU - Gensler, Helen L.
AU - Timmermann, Barbara N.
AU - Valcic, Susanne
AU - Wächter, Gerald A.
AU - Dorr, Robert
AU - Dvorakova, Katerina
AU - Alberts, David S.
N1 - Funding Information:
The authors thank J. H. Wertheim, Tea Importers, Inc., and the Royal Estates Tea Company, Division of Thomas J. Lipton, Inc., for providing green tea leaves. The authors also thank Tailiang Xie for statistical analysis; Kirsten Grahn and Roberto Rebeil for application of EGCG to mice; and Dr. Yong-Long Liu, Ming Zhao, Mark Shafer, Kay Caple, Petra Miketova, and Sabina Miranda for assistance in the isolation of large amounts of pure EGCG. This investigation was supported by National Cancer Institute Grants CA-27502 and CA-44504 from the National Institutes of Health (Bethesda, MD). Address reprint requests to Dr. Helen L. Gensler, Dept. of Radiation Oncology and Cancer Center, University of Arizona, Tucson, AZ 85724.
PY - 1996
Y1 - 1996
N2 - Topical application of purified (-)-epigallocatechin-3-gallate (EGCG), a polyphenolic antioxidant isolated from green tea, inhibited photocarcinogenesis in BALB/cAnNHsd mice with no visible toxicity. Mice were treated with 0, 10, or 50 mg of EGCG in 200 μl of acetone three times weekly for three weeks before ultraviolet (UV) treatments began and throughout the experiment. UV radiation consisted of five 30-minute exposures per week to banks of six FS40 Westinghouse sunlamps for 25 weeks. In the photocarcinogenesis study, mice received a total dose of approximately 2.1 x 106 J/m2. Skin cancer incidence in UV-irradiated mice was 96% at 28 weeks after the first UV treatment; EGCG at 10 or 50 mg reduced this incidence to 62% and 39%, respectively. UV-induced immunosuppression, assessed by the inability of UVB-irradiated mice to reject a syngeneic antigenic tumor, was not influenced by topical EGCG. Oral administration of 0, 100, or 500 mg of pure EGCG per liter of drinking water (approximately 0, 0.56, or 2.8 mg/day, respectively) did not decrease UV-induced skin tumor incidence, rate of primary tumor growth, or inability to reject antigenic tumors. Thus induction of skin tumors by UV radiation was significantly reduced by topical, but not by oral, administration of purified EGCG through a mechanism distinct from inhibition of photoimmunosuppression.
AB - Topical application of purified (-)-epigallocatechin-3-gallate (EGCG), a polyphenolic antioxidant isolated from green tea, inhibited photocarcinogenesis in BALB/cAnNHsd mice with no visible toxicity. Mice were treated with 0, 10, or 50 mg of EGCG in 200 μl of acetone three times weekly for three weeks before ultraviolet (UV) treatments began and throughout the experiment. UV radiation consisted of five 30-minute exposures per week to banks of six FS40 Westinghouse sunlamps for 25 weeks. In the photocarcinogenesis study, mice received a total dose of approximately 2.1 x 106 J/m2. Skin cancer incidence in UV-irradiated mice was 96% at 28 weeks after the first UV treatment; EGCG at 10 or 50 mg reduced this incidence to 62% and 39%, respectively. UV-induced immunosuppression, assessed by the inability of UVB-irradiated mice to reject a syngeneic antigenic tumor, was not influenced by topical EGCG. Oral administration of 0, 100, or 500 mg of pure EGCG per liter of drinking water (approximately 0, 0.56, or 2.8 mg/day, respectively) did not decrease UV-induced skin tumor incidence, rate of primary tumor growth, or inability to reject antigenic tumors. Thus induction of skin tumors by UV radiation was significantly reduced by topical, but not by oral, administration of purified EGCG through a mechanism distinct from inhibition of photoimmunosuppression.
UR - http://www.scopus.com/inward/record.url?scp=0029805039&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029805039&partnerID=8YFLogxK
U2 - 10.1080/01635589609514488
DO - 10.1080/01635589609514488
M3 - Article
C2 - 8910914
AN - SCOPUS:0029805039
VL - 26
SP - 325
EP - 335
JO - Nutrition and Cancer
JF - Nutrition and Cancer
SN - 0163-5581
IS - 3
ER -