Isolation and Characterization of Two Plasmids in Bacillus subtilis var. amylosacchariticus |
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| Authors: | Tsutomu Masuda Kunio Yamane Hideo Hirokawa Teruo Tanaka Kenji Sakaguchi Bunji Maruo |
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| Institution: | 1. Institute of Applied Microbiology, The University of Tokyo, Bunkyo-ku, Tokyo;2. Life Science Institute, Sophia University, Chiyoda-ku, Tokyo;3. Mitsubishi Kasei Institute of Life Sciences, Machida-shi, Tokyo, Japan |
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| Abstract: | Five bufadienolides (1-5) isolated from the leaves of Kalanchoe pinnata and K. daigremontiana×tubiflora (Crassulaceae) were examined for their inhibitory effects on Epstein-Barr virus early antigen (EBV-EA) activation in Raji cells induced by the tumor promoter, 12-O-tetradecanoylphorbol-13-acetate. All bufadienolides showed inhibitory activity, and bryophyllin A (1) exhibited the most marked inhibition (IC50=0.4 μM) among the tested compounds. Bryophyllin C (2), a reduction analogue of 1, and bersaldegenin-3-acetate (3) lacking the orthoacetate moiety were less active. These results strongly suggest that bufadienolides are potential cancer chemopreventive agents. |
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| Keywords: | bufadienolide Epstein-Barr virus anti-tumor promoter Kalanchoe pinnata Kalanchoe daigremontiana×tubiflora |
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