Transformation of the Diprenylated Isoflavone 2'-Hydroxylupalbigenin by Aspergillus flavus

抄録

When incubated for 3 days with a culture of Aspergillus flavus, the diprenylated isoflavonc 2'-hydroxylupalbigenin [5, 7, 2', 4'-tetrahydroxy-6, 3'-di-(3, 3-dimethylallyl)isoflavone] was converted to ten phenolic compounds which were isolated and purified by a combination of column and thinlayer chromatography. The aromatic (A/B) rings of these isoflavone-like metabolites were found to be variously substituted with acyclic dihydrohydroxy (ring A) and dihydrodihydroxy (rings A and B) sidechains, as well as with cyclic dihydrofuran (both rings) and dihydropyran (ring B) attachments resulting from fungal modification of the prenyl groups located at C-6 and C-3' on the substrate molecule. One of the metabolites (denoted AF-d-1) is spectroscopically (UV, MS and 1H-NMR) and chromatographically indistinguishable from lupinisoflavone F, a compound already known to occur constitutively in roots of the white lupin (Lupinus albus).