78(P-35) 子嚢菌Chaetomium quadrangulatumのモノアミン酸化酵素阻害活性成分(ポスター発表の部)

概要

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In our continuous screening program on monoamine oxidase (MAO) inhibitory constituents of fungi, we have recently found out that the ethyl acetate extract of an Ascomycete, Chaetomium quadrangulatum appreciably inhibits mouse liver MAO in a modified Kraml's assay. Fractionation guided by the MAO inhibitory activity has afforded five new compounds tentatively named CQ-1(1)-5(5) as the MAO inhibitory features of this fungus. Chemical reactions and spectroscopic investigations including two dimensional NMR techniques, COSY, HSQC, and HMBC, and also differential NOE, have been carried out to elucidate the structures of 1-5, including their absolute configurations. As the results, it has been clarified that 1-3 which have the common molecular formula are each other stereoisomers in their acetal-containing alkyl side chain at 6 position of chromone (1,4-benzopyran-4-one) skeleton (see Chart 1 and 2), 4 is a 6-alkylchromone containing a sulfonyl group in its alkyl side chain, and 5 is also a 6-alkylchromone (see Chart 3). The MAO inhibitory activities of 1-5 measured with the modified Kraml's method are shown in Table 1, indicating that among these five new 6-alkylchromones, 4 shows the highest MAO inhibitory activity which seems to be moderate in comparing the IC_<50> value of 4 to those of other MAO inhibitory constituents formerly isolated from other fungi by us.
天然有機化合物討論会の論文
2001-09-01