P-33 Sophora属植物由来のフラボノスチルベン及びオリゴスチルベンの構造(ポスター発表の部)

抄録

In our continuous studies on the chemosystematics of the genus Sophora (Leguminosae), we have investigated the phenolic constituents in the roots of S. alopecuroides and S. leachiana in addition to those in S. exigua, S. fraseri and S. koreensis (=Echinosophora koreensis). The roots of S. alopecuroides, collected at Xinjiang, China, were extracted with acetone, and the extract was subjected to column chromatography on silica gel. Further purification by Sephadex LH-20 c.c. and VLC resulted in the isolation of alopecurones A (1)-F (6), leachianols A (11), F (16), G (17), ε-viniferin (19) and pallidol (20). Their structural elucidation were carried out by 2D NMR evidence. The roots of S. leachiana, collected at Oregon, were pulverized and extracted with acetone, and the extract was poured into water and partitioned with benzene, EtOAc and n-BuOH, successively. By use of Si c.c., Sephadex LH-20 c.c. and VLC, two flavonostilbenes, leachianone C (9) and sophoraflavanone I (7), were isolated from the benzene extract, whereas, two flavonostilbenes, leachianone I (10) and sophoraflavanone H (8), and eight oligostilbenes, leachianols A (11)-G(17), hopeaphenol (18), ε-viniferin (19) and pallidol (20), were from the EtOAc extract. All these structures were also established by means of 2D NMR experiments. Up to now, the occurrence of flavonostilbenes which are condensed a resveratrol with a flavanone through the B-ring of a flavanone skeleton to form a dihydrofuran ring has been reported in the roots of S. leachiana and S. moorcroftiana. On the other hand, flavonostilbenes in S. alopecuroides condensed a resveratrol with a flavanone through the A-ring are different from the above flavonostilbenes. The significant differences between S. leachiana and S. moorcroftiana were summarized by the oligostilbene structures, that is, the oligostilbenes in S. leachiana are characterized as a product oligomerized through a pallidol, in contrast, the oligostilbenes in S. moorcroftiana are through an ε-viniferin. The occurrence of resveratrol oligomers in S. alopecuroides indicated close similarity to S. leachiana from the standpoint of oligostilbene production, but two species have different pathways for the biosynthesis of flavonostilbenes.