Publications by authors named "Yukinori Yamamoto"

Tubiferic acid (1), a new triterpenoid acid having a 2,6-dimethyl-4,5-dihydroxy-2-hexenoic acid moiety as a side chain, was isolated from field-collected fruit bodies of the myxomycete Tubulifera arachnoidea, and its structure was elucidated by spectral data. Tubiferic acid (1) had the same unique 9,10-secocycloartane carbon skeleton as tubiferal A (2).

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Chemical investigation of field-collected fruit bodies of the myxomycete Cribraria meylanii resulted in the isolation of a naphthoquinone pigment, cribrarione C, and its structure was elucidated by spectral data as 2,5,6,7-tetrahydroxy-1,4-naphthoquinone (1). This compound (1) had been synthesized previously, while it was isolated here for the first time as a natural product, and its NMR and MS data are described in this study.

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A new bisindole sulfate (1) and arcyroxocin B (2) were isolated from wild fruiting bodies of Arcyria denudate, along with three known bisindoles (4-6). Dihydroarcyriacyanin A (3) was obtained from wild fruiting bodies of Arcyria obvelata, along with a known bisindole (7). The structures of these compounds were elucidated on the basis of spectroscopic data, and this is the first report of full characterizations of arcyroxocin B (2) and dihydroarcyriacyanin A (3).

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Two new bisindole alkaloids, 6-hydroxystaurosporinone (1) and 5,6-dihydroxyarcyriaflavin A (2) were isolated from field-collected fruit bodies of a myxomycete Lycogala epidendrum, along with eight known bisindoles (3-10). The structures of these new compounds were determined on the basis of spectroscopic data. Compounds 1 and 2 showed cytotoxicity against HeLa, Jurkat, and vincristine resistant KB/VJ300 cells, and compound 1, particularly, inhibited protein tyrosine kinase activity.

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Two new bisindole alkaloids, named cinereapyrrole A (1) and B (2), were isolated from wild fruit bodies of Arcyria cinerea and three new bisindole alkaloids (3-5) were isolated from wild fruit bodies of Lycogala epidendrum. Seven known bisindoles (6-12) were concomitantly obtained from them. The structures of the new compounds were elucidated by spectral data.

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Cycloanthranilylproline (1) and its derivatives (2--4) were isolated from field-collected fruit-bodies of a myxomycete Fuligo candida and their structures were elucidated by spectral data. Compound 4, which was contained in the water-soluble fraction of the extract of this myxomycete, was unstable and quite susceptible to decarboxylation to yield compound 2, which was a major constituent of the EtOAc-soluble fraction of this extract.

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Cribrarione B (1), a new naphthoquinone pigment, has been isolated from the myxomycete Cribrariacancellata, and its structure was elucidated as 2,5,8-trihydroxy-6-(1-hydroxyethyl)-[1,4]-naphthoquinone by NMR and mass spectral data.

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From a myxomycete Arcyria ferruginea, dihydroarcyriarubin C (1), a new bisindole alkaloid, has been isolated together with two known bisindoles, arcyriarubin C (2) and arcyriaflavin C (3), and arcyriaflavin C (3) was also isolated from Tubifera casparyi together with arcyriaflavin B (4). Arcyriaflavin C (3) exhibited cell cycle inhibition effect at G1 and G2/M stage at 10 and 100ng/mL, respectively.

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Three new naphthoquinone pigments, 6,7-dimethoxydihydrolindbladione (1), dihydrolindbladione (2), and 6-methoxydihydrolindbladione (3), have been isolated from a myxomycete Lindbladia tubulina, and their structures were elucidated by spectral data. Compound 3 appreciably exhibited a reversal effect of multidrug resistance. Lindbladione (4), the major pigment of this myxomycete, was also isolated from Cribraria intricata.

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Lindbladione (1), 7-methoxylindbladione (2), and 6, 7-dimethoxylindbladione (3) have been isolated from a myxomycete Lindbladia tubulina and their structures were elucidated by spectral data.

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