Abstract
Seven labdane-type diterpenoids from the stem bark of Thuja standishii (Gord.) Carr. (Cupressaceae) and their analogues showed strong inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among these compounds, 15,16-bisnor-13-oxolabda-8(17), 11E-dien-19-oic acid was revealed to have the strongest inhibitory effect on the EBV-EA activation, being stronger than that of beta-carotene which has been intensively studied in cancer prevention using animal models. 15,16-bisnor-13-Oxolabda-8(17), 11E-dien-19-oic acid was also found to exhibit the excellent anti-tumor promoting activity in two-stage mouse skin carcinogenesis test using 7,12-dimethylbenz[a]anthracene and TPA.
MeSH terms
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9,10-Dimethyl-1,2-benzanthracene
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Animals
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Antigens, Viral / metabolism
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Carboxylic Acids / chemistry
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Carboxylic Acids / pharmacology*
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Carcinogens
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Diterpenes / chemistry
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Diterpenes / pharmacology*
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Female
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Humans
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Mice
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Mice, Inbred ICR
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Naphthalenes / chemistry
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Naphthalenes / pharmacology*
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Nasopharyngeal Neoplasms / prevention & control
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Neoplasms / prevention & control*
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Papilloma / prevention & control
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Plant Extracts / chemistry
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Plant Extracts / pharmacology*
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Plant Stems
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Skin Neoplasms / chemically induced
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Skin Neoplasms / prevention & control
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Tetradecanoylphorbol Acetate
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Trees
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beta Carotene / pharmacology
Substances
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15,16-bisnor-13-oxolabda-8(17),11-dien-19-oic acid
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Antigens, Viral
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Carboxylic Acids
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Carcinogens
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Diterpenes
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Epstein-Barr virus early antigen
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Naphthalenes
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Plant Extracts
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beta Carotene
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9,10-Dimethyl-1,2-benzanthracene
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Tetradecanoylphorbol Acetate