Cancer Chemopreventive Activity of Oleanane‐Type Triterpenoids from the Stem Bark of Betula ermanii |
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| Authors: | Chiharu Yamaguchi Yasuko In Shun‐ichi Wada Takeshi Yamada Harukuni Tokuda Reiko Tanaka |
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| Institution: | 1. Department of Medicinal Chemistry, Osaka University of Pharmaceutical Sciences, 4‐20‐1 Nasahara, Takatsuki, Osaka 569‐1094, Japan (phone and fax: +81‐72‐690‐1084);2. Department of Complementary and Alternative Medicine, R & D, Graduate School of Medicinal Sciences, Kanazawa University, 13‐1 Takara‐machi, Kanazawa 920‐8640, Japan |
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| 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, 3β‐acetoxy‐12α‐hydroxyoleanan‐13β,28‐olide ( 1 ) and 3β‐acetoxy‐11α,12α‐epoxyoleanan‐13β,28‐olide ( 2 ) were investigated for the inhibitory effect in a two‐stage carcinogenesis test on mouse skin using 7,12‐dimethylbenza]anthracene (DMBA) as an initiator and TPA as a promoter. 3β‐Acetoxy‐11α,12α‐epoxyoleanan‐13β,28‐olide ( 2 ) was found to exhibit the potent antitumor promoting activity in the in vivo carcinogenesis test. |
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| Keywords: | Betula ermanii Triterpenoids Oleananes Cancer chemopreventive activity |
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