Hideo Etoh

Three pterocarpans from Erythrina crista-galli

Abstract Three new pterocarpans, erystagallins A–C, were isolated from the wood of Erythrina cristagalli , together with the three known pterocarpans, cristacarpin, phaseollidin and 2-(γ,γ-dimethylallyl)-6a-hydroxyphaseollidin. Their structures were elucidated on the basis of the spectroscopic evidence.

Two pterocarpans from Erythrina orientalis

A new pterocarpan, hydroxycristacarpone, was isolated from the wood of Erythrina orientalis and the structure was established as a 11b-hydroxydienone. Three known compounds, the pterocarpan, crystacarpin and the isoflavones osajin and wighteone, were also characterized.

Four new isoflavonoids and a new 2-arylbenzofuran from the roots of Erythrina variegata

Two new isoflavonoids, eryvarins S (1) and T (2), and a new 2-arylbenzofuran, eryvarin U (3), together with nine known compounds, were isolated from the roots of Erythrina variegata. Their structures were established on the basis of spectroscopic analysis. Eryvarin U is a rare naturally-occurring 2-arylbenzofuran. The antibacterial activity of these three new compounds against 13 strains of methicillin-resistant Staphylococcus aureus (MRSA) was examined in which eryvarin U showed the highest antibacterial activity.

An isoflavan from Erythrina x bidwillii

Abstract A new isoflavan, erythbidin A, was isolated from the wood of Erythrina x bidwillii , together with three known isoflavans, phaseollinisoflavan, 2′-methoxyphaseollinisoflavan, and 2′- O -methylphaseollidinisoflavan and another pterocarpan, sandwicensin. Erythbidin A has a dimethylpyrene substitution at the 2′,3′-position.

Erythrinan alkaloid from Erythrina x bidwillii

A new alkaloid, erythbidin B, was isolated from flowers of Erythrina x bidwillii, together with the three known alkaloids, erythraline, erysodine and erythrinine. Their structures were elucidated on the basis of spectroscopic evidence.

Three isoflavanones from erythrina orientalis

Abstract Three new isoflavanones, orientanols D-F, were isolated from the roots of Erythrina orientalis L, together with the two known isoflavanones, bidwillon A and bidwillon B. Their structures were elucidated on the basis of spectroscopic evidence.