77(P2-7) カヤツリグサ科コウボウムギに含まれる抗菌性テトラスチルベン、kobophenol Aの構造(ポスター発表の部)  [in Japanese] 77(P2-7) KOBOPHENOL A, AN ANTIBACTERIAL TETRASTILBENE FROM CAREX KOBOMUGI OHWI (CYPERACEAE)  [in Japanese]

In the course of our search for antibacterial oligostilbenes in Carex spp. (Cyperaceae), a novel tetrastilbene named kobophenol A (5), having a unique 2,3,4,5-tetraaryltetrahydrofuran unit, has been isolated from subterranean parts of C. kobomugi Ohwi. Methanol extracts of fresh roots and rhizoma of C. kobomugi were fractionated by a series of solvent partitions followed by column and thin layer chromatography to afford a major active principle, kobophenol A (5), as a pale yellow oil along with previously known oligostilbenes, miyabenol C (3) and ε-viniferin (4). All isolates showed antibacterial activity against Staphylococcus aureus. Kobophenol A (5) has a molecular formula of C_<56>H_<44>O_<13>, which corresponds to a tetrastilbene. Permethylation of 5 yielded a decamethyl ether (6). The plane structure of 5 was elucidated principally with the aid of 2D-NMR (HH-, CH- and long range CH-COSY) as well as the UV and 1D-NMR results. The EI-MS fragmentation pattern of 6 well supports this structure. The relative stereochemistry of 5 has been assigned from results of 2D PSNOESY and 1D NOE difference spectrum experiments as rel-(7aR,8aR,7bS,8bS,7cS,8cS,7dS,8dR).