Abstract
In search for cancer chemopreventive agents from natural sources, three oleanane- and four known lupane-type triterpenoids, and sitosterol from the stem bark of Betula ermanii were tested for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). Among them, 3beta-acetoxy-12alpha-hydroxyoleanan-13beta,28-olide (1) and 3beta-acetoxy-11alpha,12alpha-epoxyoleanan-13beta,28-olide (2) were investigated for the inhibitory effect in a two-stage carcinogenesis test on mouse skin using 7,12-dimethylbenz[a]anthracene (DMBA) as an initiator and TPA as a promoter. 3beta-Acetoxy-11alpha,12alpha-epoxyoleanan-13beta,28-olide (2) was found to exhibit the potent antitumor promoting activity in the in vivo carcinogenesis test.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Anticarcinogenic Agents / chemistry*
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Anticarcinogenic Agents / isolation & purification
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Anticarcinogenic Agents / pharmacology
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Antigens, Viral / drug effects
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Antigens, Viral / metabolism
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Betula / chemistry*
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Carcinogenicity Tests
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Female
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Mice
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Mice, Inbred ICR
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Oleanolic Acid / analogs & derivatives*
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Oleanolic Acid / chemistry
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Papilloma / chemically induced
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Papilloma / prevention & control
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Plant Bark / chemistry
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Plant Stems / chemistry
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Skin Neoplasms / chemically induced
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Skin Neoplasms / prevention & control
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Tetradecanoylphorbol Acetate / pharmacology
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Triterpenes / chemistry*
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Triterpenes / isolation & purification
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Triterpenes / pharmacology
Substances
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Anticarcinogenic Agents
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Antigens, Viral
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Epstein-Barr virus early antigen
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Triterpenes
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oleanane
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Oleanolic Acid
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Tetradecanoylphorbol Acetate