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Hoyoku Nishino - One of the best experts on this subject based on the ideXlab platform.
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cancer preventive agents part 5 anti tumor promoting effects of coumarins and related compounds on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Pharmaceutical Biology, 2006Co-Authors: Madoka Suzuki, Harukuni Tokuda, Mutsuo Kozuka, Hoyoku Nishino, Kyoko Nakagawagoto, Seikou Nakamura, Susan L Morrisnatschke, Kuo Hsiung LeeAbstract:AbstractA series of coumarins and related compounds were synthesized and screened as potential anti-tumor-promoting agents by examining the ability of the compound to inhibit Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O.-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. The most promising compound in this in vitro. assay, 7,8-di(3-methyl-2-butenyloxy)coumarin (17), showed confirmed chemopreventive activity in an in vivo. two-stage assay of mouse skin tumors (DMBA/TPA). This investigation also confirmed an important role for the prenyl moiety, and, possibly, for the dimethylpyran substructure, on the anti-tumor-promoting activity.
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cancer chemopreventive activity of acridone alkaloids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2003Co-Authors: Fumio Enjo, Masataka Itoigawa, Harukuni Tokuda, Hoyoku Nishino, Chihiro Ito, Hiroshi FurukawaAbstract:Seventeen acridone alkaloids isolated from the Rutaceous plants were tested for their inhibitory activities against Epstein-Barr Virus early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some prenylated acridones were found to have remarkably potent activities. 1,3-Dihydroxy-10-methyl-2,4-diprenylacridone (18) as synthesized according to these results in vitro, exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these acridone alkaloids may be potentially valuable cancer chemopreventive agents.
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antitumor agents 220 antitumor promoting effects of cimigenol and related compounds on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Bioorganic & Medicinal Chemistry, 2003Co-Authors: Nobuko Sakurai, Harukuni Tokuda, Junko Takayasu, Mutsuo Kozuka, Hoyoku Nishino, Yoshitaka Nobukuni, A Kusano, Genjiro Kusano, Masahiro Nagai, Yojiro SakuraiAbstract:Abstract Cimigenol ( 1 ) and 39 related compounds were screened as potential antitumor promoters by examining the ability of the compounds to inhibit Epstein–Barr Virus early antigen (EBV-EA) Activation (induced by 12- O -tetradecanoylphorbol-13-acetate) in Raji cells. Structure–activity relationship analysis indicated that compound 1 showed the highest activity and also exhibited significant inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These data suggest that 1 and the related compounds might be valuable anti-tumor promoters.
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inhibitory effects of lapachol derivatives on epstein barr Virus Activation
Bioorganic & Medicinal Chemistry, 2003Co-Authors: Elisa Perez Sacau, Teruo Mukainaka, Angel G Ravelo, Ana Estevezbraun, Esteban Ferro, Harunkuni Tokuda, Hoyoku NishinoAbstract:Sixteen derivatives (2-17) synthesized from the naphthoquinone lapachol (1), were tested for their inhibitory effects on Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA), as a test for potential cancer chemopreventive agents. They exhibited a variety of inhibitory activities from very high to moderate, which allow us to suggest structure-activity relationships. Ten of these derivatives are reported for the first time, their structures being thoroughly determined by spectroscopic methods.
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Cancer chemopreventive effect of quassinoid derivatives. Introduction of side chain to shinjulactone C for enhancement of inhibitory effect on Epstein-Barr Virus Activation.
Cancer Letters, 2002Co-Authors: Sadaaki Tamura, Teruo Mukainaka, Harukuni Tokuda, Narihiko Fukamiya, Masayoshi Okano, Kiyoshi Tagahara, Hoyoku Nishino, Kazuo KoikeAbstract:A series of shinjulactone C (1) derivatives (2-8) were synthesized and evaluated for their anti-tumor promoting effects against Epstein-Barr Virus early antigen Activation introduced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. The succinate and 3',3'-dimethylsuccinate derivatives of 1 exhibited higher inhibitory effects than 1. From the point of view of structure-activity relationships, the succinate derivatives (2, 4) demonstrated better potency than the glutarate derivatives (3, 5-8). As substituted moieties of 3'-position became bulky, the inhibitory effects of the glutarate derivatives (7, 8) significantly decreased.
Harukuni Tokuda - One of the best experts on this subject based on the ideXlab platform.
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cancer preventive agents 7 antitumor promoting effects of seven active flavonolignans from milk thistle silybum marianum on epstein barr Virus Activation
Pharmaceutical Biology, 2007Co-Authors: An Shen Lin, Harukuni Tokuda, Kyoko Nakagawagoto, Susan L Morrisnatschke, Makio Shibano, Hideji Itokawa, Kuo Hsiung LeeAbstract:Seven pure flavonolignans were isolated from an extract of milk thistle [Silybum marianum (L.) Gaertn (Asteraceae)], by semipreparative reverse-phase HPLC, and identified based on spectroscopic and LC-MS=IT-TOF data. All seven compounds were screened as potential antitumor-promoting agents by using the in vitro short-term 12-O-tetradecanoylphorbol-13-acetate (TPA)induced Epstein-Barr Virus early antigen (EBV-EA) Activation assay in Raji cells. They showed good inhibitory activity (87.7–94.9%) at 1000 mol ratio=TPA. Silychristin A (1) and silychristin B (2) were slightly more potent than the well-known antitumor promoter b-carotene. Silychristins A (1) and B (2) and isosilybins A (6 )a nd B( 7) were more active than the clinically proven cancer prevention components silybins A (4) and B (5).
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cancer preventive agents part 5 anti tumor promoting effects of coumarins and related compounds on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Pharmaceutical Biology, 2006Co-Authors: Madoka Suzuki, Harukuni Tokuda, Mutsuo Kozuka, Hoyoku Nishino, Kyoko Nakagawagoto, Seikou Nakamura, Susan L Morrisnatschke, Kuo Hsiung LeeAbstract:AbstractA series of coumarins and related compounds were synthesized and screened as potential anti-tumor-promoting agents by examining the ability of the compound to inhibit Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O.-tetradecanoylphorbol-13-acetate (TPA) in Raji cells. The most promising compound in this in vitro. assay, 7,8-di(3-methyl-2-butenyloxy)coumarin (17), showed confirmed chemopreventive activity in an in vivo. two-stage assay of mouse skin tumors (DMBA/TPA). This investigation also confirmed an important role for the prenyl moiety, and, possibly, for the dimethylpyran substructure, on the anti-tumor-promoting activity.
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sterol ferulates sterols and 5 alk en ylresorcinols from wheat rye and corn bran oils and their inhibitory effects on epstein barr Virus Activation
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Kenji Iwatsuki, Hiroshi Higashihara, Masao Iizuka, Motohiko Ukiya, Teruo Mukainaka, Yoshiharu Hayashi, Toshihiro Akihisa, Harukuni Tokuda, Yumiko KimuraAbstract:Sterol ferulate, free sterol, and 5-alk(en)ylresorcinol constituents of wheat, rye, and corn bran oils were studied. Among the sterol ferulates, one novel compound, 24-methylenecholestanol ferulate (7), along with six known compounds, namely, 24-methylcholestanol ferulate (1), 24-methylcholesterol ferulate (2), 2-methyllathosterol ferulate (3), stigmastanol ferulate (4), sitosterol ferulate (5), and schottenol ferulate (6), were isolated and characterized. Five known free sterols, namely, 24-methylcholesterol (8), stigmastanol (9), sitosterol (10), schottenol (11), and stigmasterol (12), were isolated and identified. 5-Alk(en)ylresorcinols were found in wheat and rye bran oils but not in corn bran oil. Of these, one new compound, 5-n-(2‘-oxo-14‘-Z-heneicosenyl) resorcinol (19), and seven known compounds, namely, 5-n-heptadecyl- (13), 5-n-nonadecyl- (14), 5-n-heneicosyl- (15), 5-n-tricosyl- (16), 5-n-pentacosyl- (17), 5-n-(14‘-Z-nonadecenyl)- (18), and 5-n-(2‘-oxoheneicosyl)resorcinols (20), were isolated ...
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cancer chemopreventive activity of acridone alkaloids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2003Co-Authors: Fumio Enjo, Masataka Itoigawa, Harukuni Tokuda, Hoyoku Nishino, Chihiro Ito, Hiroshi FurukawaAbstract:Seventeen acridone alkaloids isolated from the Rutaceous plants were tested for their inhibitory activities against Epstein-Barr Virus early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some prenylated acridones were found to have remarkably potent activities. 1,3-Dihydroxy-10-methyl-2,4-diprenylacridone (18) as synthesized according to these results in vitro, exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these acridone alkaloids may be potentially valuable cancer chemopreventive agents.
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antitumor agents 220 antitumor promoting effects of cimigenol and related compounds on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Bioorganic & Medicinal Chemistry, 2003Co-Authors: Nobuko Sakurai, Harukuni Tokuda, Junko Takayasu, Mutsuo Kozuka, Hoyoku Nishino, Yoshitaka Nobukuni, A Kusano, Genjiro Kusano, Masahiro Nagai, Yojiro SakuraiAbstract:Abstract Cimigenol ( 1 ) and 39 related compounds were screened as potential antitumor promoters by examining the ability of the compounds to inhibit Epstein–Barr Virus early antigen (EBV-EA) Activation (induced by 12- O -tetradecanoylphorbol-13-acetate) in Raji cells. Structure–activity relationship analysis indicated that compound 1 showed the highest activity and also exhibited significant inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These data suggest that 1 and the related compounds might be valuable anti-tumor promoters.
Hiroshi Furukawa - One of the best experts on this subject based on the ideXlab platform.
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cancer chemopreventive activity of acridone alkaloids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2003Co-Authors: Fumio Enjo, Masataka Itoigawa, Harukuni Tokuda, Hoyoku Nishino, Chihiro Ito, Hiroshi FurukawaAbstract:Seventeen acridone alkaloids isolated from the Rutaceous plants were tested for their inhibitory activities against Epstein-Barr Virus early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some prenylated acridones were found to have remarkably potent activities. 1,3-Dihydroxy-10-methyl-2,4-diprenylacridone (18) as synthesized according to these results in vitro, exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these acridone alkaloids may be potentially valuable cancer chemopreventive agents.
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cancer chemopreventive activity of flavanones on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2002Co-Authors: Masataka Itoigawa, Harukuni Tokuda, Eiichiro Ichiishi, Hoyoku Nishino, Chihiro Ito, Motoharu Juichi, Toshihiro Nobukuni, Hiroshi FurukawaAbstract:To search for possible cancer chemopreventive agents from natural sources, we performed primary screening of ten flavanones isolated from plants belonging to Rutaceae and Leguminosae by examining their possible inhibitory effects on Epstein-Barr Virus (EBV) early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the flavanones tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Amorilin (3), which has three prenyl (3-methyl-2-butenyl) side-chains in the molecule, showed the most potent activity. Furthermore, lupinifolin (5) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These results indicate that some of these prenylated flavanones might be valuable as potential cancer chemopreventive agents (anti-tumor promoters).
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inhibitory effect of flavonoid derivatives on epstein barr Virus Activation and two stage carcinogenesis of skin tumors
Cancer Letters, 2001Co-Authors: Yukiko Iwase, Teruo Mukainaka, Harukuni Tokuda, Hiroshi Furukawa, Eiichiro Ichiishi, Chihiro Ito, Yuko Takemura, Motoharu Juichi, Masamichi Yano, Hoyoku NishinoAbstract:To search for possible anti-tumor promoters, ten flavonoid derivatives (1-10) synthesized from morin and quercetin were examined for their inhibitory effects on the Epstein-Barr Virus early antigen (EBV-EA) Activation by a short-term in vitro assay. Of these compounds, pentaallyl ethers (9, 10) showed significant inhibitory effects on EBV-EA Activation induced by the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate. Further, quercetin pentaallyl ether (10) exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.
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inhibitory effect of flavonoids from citrus plants on epstein barr Virus Activation and two stage carcinogenesis of skin tumors
Cancer Letters, 2000Co-Authors: Yukiko Iwase, Hiroshi Furukawa, Junko Takayasu, Xiao Yang Mou, Chihiro Ito, Yuko Takemura, Motoharu Juichi, Masamichi Yano, Satoru Kawaii, Harukuni TokudaAbstract:To search for possible anti-tumor promoters, thirteen flavones (1-13) obtained from the peel of Citrus plants were examined for their inhibitory effects on the Epstein-Barr Virus early antigen (EBV-EA) Activation by a short-term in vitro assay. Of these flavones, 3,5,6,7,8,3',4'-heptamethoxyflavone (HPT) (13) exhibited significant inhibitory effects on the EBV-EA Activation induced by the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA). Further, compound 13 exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.
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anti tumor promoting effects of isoflavonoids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 1999Co-Authors: Chihiro Ito, Teruo Mukainaka, Masataka Itoigawa, Harukuni Tokuda, Hiroshi Furukawa, Eiichiro Ichiishi, Masato Okuda, Masakazu Ogata, Hoyoku NishinoAbstract:As a part of screening studies for anti-tumor promoters, fifteen isoflavonoids isolated from plants of the genus Millettia (Leguminosae) were evaluated by examining their possible inhibitory effects on Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Auriculasin (11) and millepurone (13), which is an oxidized isoflavone analogue, both having one or more prenyl side-chains and a 3',4'-dihydroxyphenyl group in the molecule, showed more potent activity than any of the other compounds tested. Furthermore, millepurone (13) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these isoflavonoids might be valuable anti-tumor promoters.
Masataka Itoigawa - One of the best experts on this subject based on the ideXlab platform.
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cancer chemopreventive activity of acridone alkaloids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2003Co-Authors: Fumio Enjo, Masataka Itoigawa, Harukuni Tokuda, Hoyoku Nishino, Chihiro Ito, Hiroshi FurukawaAbstract:Seventeen acridone alkaloids isolated from the Rutaceous plants were tested for their inhibitory activities against Epstein-Barr Virus early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some prenylated acridones were found to have remarkably potent activities. 1,3-Dihydroxy-10-methyl-2,4-diprenylacridone (18) as synthesized according to these results in vitro, exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these acridone alkaloids may be potentially valuable cancer chemopreventive agents.
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cancer chemopreventive activity of flavanones on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2002Co-Authors: Masataka Itoigawa, Harukuni Tokuda, Eiichiro Ichiishi, Hoyoku Nishino, Chihiro Ito, Motoharu Juichi, Toshihiro Nobukuni, Hiroshi FurukawaAbstract:To search for possible cancer chemopreventive agents from natural sources, we performed primary screening of ten flavanones isolated from plants belonging to Rutaceae and Leguminosae by examining their possible inhibitory effects on Epstein-Barr Virus (EBV) early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the flavanones tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Amorilin (3), which has three prenyl (3-methyl-2-butenyl) side-chains in the molecule, showed the most potent activity. Furthermore, lupinifolin (5) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These results indicate that some of these prenylated flavanones might be valuable as potential cancer chemopreventive agents (anti-tumor promoters).
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anti tumor promoting effects of isoflavonoids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 1999Co-Authors: Chihiro Ito, Teruo Mukainaka, Masataka Itoigawa, Harukuni Tokuda, Hiroshi Furukawa, Eiichiro Ichiishi, Masato Okuda, Masakazu Ogata, Hoyoku NishinoAbstract:As a part of screening studies for anti-tumor promoters, fifteen isoflavonoids isolated from plants of the genus Millettia (Leguminosae) were evaluated by examining their possible inhibitory effects on Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Auriculasin (11) and millepurone (13), which is an oxidized isoflavone analogue, both having one or more prenyl side-chains and a 3',4'-dihydroxyphenyl group in the molecule, showed more potent activity than any of the other compounds tested. Furthermore, millepurone (13) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these isoflavonoids might be valuable anti-tumor promoters.
Chihiro Ito - One of the best experts on this subject based on the ideXlab platform.
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cancer chemopreventive activity of acridone alkaloids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2003Co-Authors: Fumio Enjo, Masataka Itoigawa, Harukuni Tokuda, Hoyoku Nishino, Chihiro Ito, Hiroshi FurukawaAbstract:Seventeen acridone alkaloids isolated from the Rutaceous plants were tested for their inhibitory activities against Epstein-Barr Virus early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. Some prenylated acridones were found to have remarkably potent activities. 1,3-Dihydroxy-10-methyl-2,4-diprenylacridone (18) as synthesized according to these results in vitro, exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The result of the present investigation indicated that some of these acridone alkaloids may be potentially valuable cancer chemopreventive agents.
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cancer chemopreventive activity of flavanones on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 2002Co-Authors: Masataka Itoigawa, Harukuni Tokuda, Eiichiro Ichiishi, Hoyoku Nishino, Chihiro Ito, Motoharu Juichi, Toshihiro Nobukuni, Hiroshi FurukawaAbstract:To search for possible cancer chemopreventive agents from natural sources, we performed primary screening of ten flavanones isolated from plants belonging to Rutaceae and Leguminosae by examining their possible inhibitory effects on Epstein-Barr Virus (EBV) early antigen Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the flavanones tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Amorilin (3), which has three prenyl (3-methyl-2-butenyl) side-chains in the molecule, showed the most potent activity. Furthermore, lupinifolin (5) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. These results indicate that some of these prenylated flavanones might be valuable as potential cancer chemopreventive agents (anti-tumor promoters).
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inhibitory effect of flavonoid derivatives on epstein barr Virus Activation and two stage carcinogenesis of skin tumors
Cancer Letters, 2001Co-Authors: Yukiko Iwase, Teruo Mukainaka, Harukuni Tokuda, Hiroshi Furukawa, Eiichiro Ichiishi, Chihiro Ito, Yuko Takemura, Motoharu Juichi, Masamichi Yano, Hoyoku NishinoAbstract:To search for possible anti-tumor promoters, ten flavonoid derivatives (1-10) synthesized from morin and quercetin were examined for their inhibitory effects on the Epstein-Barr Virus early antigen (EBV-EA) Activation by a short-term in vitro assay. Of these compounds, pentaallyl ethers (9, 10) showed significant inhibitory effects on EBV-EA Activation induced by the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate. Further, quercetin pentaallyl ether (10) exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.
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inhibitory effect of flavonoids from citrus plants on epstein barr Virus Activation and two stage carcinogenesis of skin tumors
Cancer Letters, 2000Co-Authors: Yukiko Iwase, Hiroshi Furukawa, Junko Takayasu, Xiao Yang Mou, Chihiro Ito, Yuko Takemura, Motoharu Juichi, Masamichi Yano, Satoru Kawaii, Harukuni TokudaAbstract:To search for possible anti-tumor promoters, thirteen flavones (1-13) obtained from the peel of Citrus plants were examined for their inhibitory effects on the Epstein-Barr Virus early antigen (EBV-EA) Activation by a short-term in vitro assay. Of these flavones, 3,5,6,7,8,3',4'-heptamethoxyflavone (HPT) (13) exhibited significant inhibitory effects on the EBV-EA Activation induced by the tumor promoter, 12-O-tetradecanoylphorbol 13-acetate (TPA). Further, compound 13 exhibited remarkable inhibitory effects on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test.
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anti tumor promoting effects of isoflavonoids on epstein barr Virus Activation and two stage mouse skin carcinogenesis
Cancer Letters, 1999Co-Authors: Chihiro Ito, Teruo Mukainaka, Masataka Itoigawa, Harukuni Tokuda, Hiroshi Furukawa, Eiichiro Ichiishi, Masato Okuda, Masakazu Ogata, Hoyoku NishinoAbstract:As a part of screening studies for anti-tumor promoters, fifteen isoflavonoids isolated from plants of the genus Millettia (Leguminosae) were evaluated by examining their possible inhibitory effects on Epstein-Barr Virus early antigen (EBV-EA) Activation induced by 12-O-tetradecanoylphorbol-13-acetate in Raji cells. All of the compounds tested in this study showed inhibitory activity against EBV, without showing any cytotoxicity. Auriculasin (11) and millepurone (13), which is an oxidized isoflavone analogue, both having one or more prenyl side-chains and a 3',4'-dihydroxyphenyl group in the molecule, showed more potent activity than any of the other compounds tested. Furthermore, millepurone (13) exhibited a marked inhibitory effect on mouse skin tumor promotion in an in vivo two-stage carcinogenesis test. The results of the present investigation indicate that some of these isoflavonoids might be valuable anti-tumor promoters.
