Protection against ultraviolet B radiation-induced effects in the skin of SKH-1 hairless mice by a polyphenolic fraction isolated from green tea.
In prior studies we and others have shown that oral feeding of a polyphenolic fraction isolated from green tea (GTP) or water extract of green tea affords protection against ultraviolet B (UVB) radiation-induced carcinogenesis in SKH-1 hairless mice (Wang et al., Carcinogenesis 12, 1527-1530, 1991). It is known that exposure of murine skin to UVB radiation results in cutaneous edema, depletion of the antioxidant-defense system and induction of ornithine decarboxylase (ODC) and cyclooxygenase activities. In this study we assessed the protective effect of GTP on these UVB radiation-caused changes in murine skin. Oral feeding of 0.2% GTP (wt/vol) as the sole source of drinking water for 30 days to SKH-1 hairless mice followed by irradiation with UVB (900 mJ/cm2) resulted in significant protection against UVB radiation-caused cutaneous edema (P < 0.0005) and depletion of the antioxidant-defense system in epidermis (P < 0.01-0.02). The oral feeding of GTP also resulted in significant protection against UVB radiation-caused induction of epidermal ODC (P < 0.005-0.01) and cyclooxygenase activities (P < 0.0001) in a time-dependent manner. Our data indicate that the inhibition of UVB radiation-caused changes in these markers of tumor promotion in murine skin by GTP may be one of the possible mechanisms of chemopreventive effects associated with green tea against UVB-induced tumorigenesis. The results of this study suggest that green tea, specifically polyphenols present therein, may be useful against inflammatory responses associated with the exposure of skin to solar radiation.
Agarwal
R
R
Department of Dermatology, University Hospitals of Cleveland, OH.
Katiyar
S K
SK
Khan
S G
SG
Mukhtar
H
H
D000284:Administration, Oral; D000818:Animals; D002374:Catalase / Q000187:drug effects; D002392:Catechin / Q000031:analogs & derivatives*; D004487:Edema / Q000517:prevention & control; D004790:Enzyme Induction / Q000187:drug effects; D005260:Female; D005419:Flavonoids; D005980:Glutathione Reductase / Q000187:drug effects; D051379:Mice; D008812:Mice, Hairless; D009955:Ornithine Decarboxylase / Q000187:drug effects; D010636:Phenols / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D010936:Plant Extracts / Q000008:administration & dosage / Q000494:pharmacology*; D011108:Polymers / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D011451:Prostaglandin-Endoperoxide Synthases / Q000187:drug effects; D011837:Radiation-Protective Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D012867:Skin / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects*; D013662:Tea / Q000737:chemistry*; D013997:Time Factors; D014466:Ultraviolet Rays
D005419:Flavonoids; D010636:Phenols; D010936:Plant Extracts; D011108:Polymers; D011837:Radiation-Protective Agents; D013662:Tea; D002392:Catechin; D002374:Catalase; D011451:Prostaglandin-Endoperoxide Synthases; D005980:Glutathione Reductase; D009955:Ornithine Decarboxylase