Abstract
Chronic exposure of the skin to ultraviolet B (UVB) radiation induces oxidative stress, which plays a crucial role in the induction of skin cancer. In this study, the effect of dietary feeding and topical application of brown algae polyphenols on UVB radiation-induced skin carcinogenesis in SKH-1 mice was investigated. SKH-1 hairless mice were randomly divided into 9 groups, including control, UVB control and treatment groups. They were treated orally (0.1% and 0.5% with AIN-76 diet, w/w) and topically (3 and 6 mg/0.2 ml of vehicle) with brown algae polyphenols and irradiated with UVB for 26 weeks. Dietary feeding (0.1% and 0.5%) of brown algae polyphenols significantly reduced tumor multiplicity (45% and 56%) and tumor volume (54% and 65%), and topical administration (3 and 6 mg) significantly decreased tumor multiplicity (60% and 46%) and tumor volume (66% and 57%), respectively, per tumor-bearing mouse. Dietary feeding and topical administration of the polyphenols also inhibited tumor incidence by 6% and 21%, respectively, but the results were not significant. Dietary and topical administration of the polyphenols markedly inhibited cyclooxygenase-2 activity and cell proliferation. These observations show that brown algae polyphenols have an antiphotocarcinogenic effect which may be associated with the prevention of UVB-induced oxidative stress, inflammation, and cell proliferation in the skin.
Copyright 2006 Wiley-Liss, Inc.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Administration, Cutaneous
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Administration, Oral
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Animals
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Benzofurans / administration & dosage
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Benzofurans / chemistry
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Benzofurans / pharmacology
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Blotting, Western
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Cell Proliferation / drug effects
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Cell Proliferation / radiation effects
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Cyclooxygenase 2 / genetics
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Cyclooxygenase 2 / metabolism
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Dinoprostone / metabolism
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Dioxins / administration & dosage
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Dioxins / chemistry
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Dioxins / pharmacology
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Epidermis / drug effects
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Epidermis / metabolism
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Epidermis / radiation effects
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Female
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Flavonoids / administration & dosage
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Flavonoids / chemistry
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Flavonoids / pharmacology*
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Gene Expression / drug effects
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Gene Expression / radiation effects
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Immunohistochemistry
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Mice
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Molecular Structure
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Neoplasms, Radiation-Induced / genetics
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Neoplasms, Radiation-Induced / metabolism
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Neoplasms, Radiation-Induced / prevention & control
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Phaeophyceae / chemistry*
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Phenols / administration & dosage
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Phenols / chemistry
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Phenols / pharmacology*
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Polyphenols
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Proliferating Cell Nuclear Antigen / analysis
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Random Allocation
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Reverse Transcriptase Polymerase Chain Reaction
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Skin / drug effects*
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Skin / pathology
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Skin / radiation effects
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Skin Neoplasms / etiology
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Skin Neoplasms / metabolism
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Skin Neoplasms / prevention & control*
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Ultraviolet Rays / adverse effects*
Substances
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Benzofurans
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Dioxins
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Flavonoids
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Phenols
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Polyphenols
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Proliferating Cell Nuclear Antigen
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dieckol
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6,6'-bieckol
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eckol
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Cyclooxygenase 2
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Dinoprostone