Masae Yamaki

Antimicrobial agents from Bletilla striata

Abstract Three new bibenzyls and two new dihydrophenanthrenes, which exhibit antimicrobial activity, were isolated from tubers of Bletilla striata. They were identified by various spectroscopic methods.

Biphenanthrenes from Bletilla striata

Abstract From tubers of Bletilla striata , three new biphenanthrenes were isolated, together with batatasin Ill and 3′-O-methylbatatasin III. The structures were elucidated from their spectroscopic data.

Blestrianol A, B and C, biphenanthrenes from Bletilla striata

Abstract Three biphenanthrenes, blestrianol A, B and C and one dibenzylphenanthrene were isolated from tubers of Bletilla striata . The structures were elucidated as 4,4′-dimethoxy-9,9′,10,10′-tetrahydro-[1′,3-biphenanthrene]-2,2′,7,7′-tetraol, 4′,5-dimethoxy-8-(4-hydroxybenzyl)-9,9′,10,10′-tetrahydro-[1′,3-biphenanthrene]-2,2′,7,7′-tetraol,4′,5-dimethoxy-8-(4-hydroxybenzyl)-9,10-dihydro-[1′,3-biphenanthrene]-2,2′,7,7′-tetraol and 1,8-bi(4-hydroxybenzyl)-4-methoxy-phenanthrene-2,7-diol by their spectroscopic data.

Phenanthrenes from Dendrobium plicatile

From Dendrobium plicatile stems, three phenanthrenes were isolated. The structures are 2,5-dihydroxy-4,9,10-trimethoxyphenanthrene, 2,5-dihydroxy-4-methoxyphenanthrene and 2,5,9-trihydroxy-4-methoxy-9,10-dihydrophenanthrene.

Stilbenoids from Bletilla striata

Abstract Five new stilbenoids, three bibenzyls, one dibenzyldihydrophenanthrene and one benzoyldihydrophenanthrene, were isolated from tubers of Bletilla striata . The new structures were elucidated as 3,3′-dihydroxy-4-( p -hydroxybenzyl)-5-methoxybibenzyl, 3,3′-dihydroxy-2-( p -hydroxybenzyl)-5-methoxybibenzyl, 3′,5-dihydroxy-2-( p -hydroxybenzyl)-3-methoxybibenzyl, 2,7-dihydroxy-1,3-bi( p -hydroxybenzyl)-4-methoxy-9,10-dihydrophenanthrene and 2,7-dihydroxy-1-( p -hydroxybenzoyl)-4-methoxy-9,10-dihydrophenanthrene, by their spectroscopic data.

The stilbenoids from Dendrobium plicatile

Abstract Seven stilbenoids were isolated from stems of Dendrobium plicatile and their structures were elucidated on the basis of spectroscopic data. Six of them were known compounds, 3-methoxy-3′,5-dihydroxybibenzyl, 3,3′,4′-trimethoxy-5-hydroxybibenzyl, 2-methoxy-4,7-dihydroxy-9,10-dihydrophenanthrene, 2,4-dimethoxy-3,7-dihydroxyphenanthrene, 3,4-dimethoxy-2,7-dihydroxy-9,10-dihydrophenanthrene and ephemeranthoquionone. The seventh, 2,2′-dimethoxy-4,4′,7,7′-tetrahydroxy-9,9′,10,10′-tetrahydro-1,1′-biphenanthrene, was a new dimer.

An isopentenylated flavonol from Hypericum japonicum

Abstract A new isopentenylated flavonol, salothranol, from whole plants of Hypericum japonicum was isolated together with the known isojacareubin. Its struc

Four stilbenoids from Pleione bulbocodioides

Abstract Two dihydrophenanthropyrans, shanciol E and F, and two bibenzyls, bulbocodin C and D, were isolated from tubers of Pleione bulbocodioides . The new structures were elucidated to be 3-hydroxy-11-methoxy-2-(4′-hydroxy-3′,5′-dimethoxyphenyl)-2,3,5,6-tetrahydro-4H-phenanthro[2,1-b] pyran-8-ol; 4-hydroxy-11-methoxy-3-(4′-hydroxy-3′-methoxyphenyl)-3,4,5,6-tetrahydro-2H-pehnanthro[2,1-b] pyran-8-ol; 3′,5-dihydroxy-3-methoxy-2,4-di( p -hydroxybenzyl)bibenzyl; 3,3′-dihydroxy-5-methoxy-2,4-di( p -hydroxybenzyl)bibenzyl; respectively, on the basis of spectroscopic data and chemical correlations.

A polyphenol and two bibenzyls from Pleione bulbocodioides

Abstract From tubers of Pleione bulbocodioides , one new polyphenol, pleionol, and two new bibenzyls, bulbocodin and bulbocol were isolated together with three known compounds, 3,3′-dihydroxy-4-( p -hydroxybenzyl)-5-methoxybibenzyl, 3,3′-dihydroxy-2-( p -hydroxybenzyl)-5-methoxybibenzyl, 3′,5-dihydroxy-2-( p -hydroxybenzyl)-3-methoxybibenzyl. The new structures were elucidated as 2,8-dihydroxy-5-(4′-hydroxy-3′-methoxyphenyl)-4-methoxy-10,11-dihydrodibenzo[a,d]cycloheptene, 2′,3-dihydroxy-5-methoxy-2,5′,6-tri( p -hydroxybenzyl)bibenzyl and 3,3′-dimethoxy-5-hydroxy-2-( p -hydroxybenzyl)bibenzyl from their spectroscopic data.

A flavanonol rhamnoside from Hypericum japonicum

Abstract A new flavanonol (2R,3R)-taxifolin-7-rhamnoside, from whole plant of Hypericum japonicum has been isolated together with the known quercitrin and vincetoxicoside B. Their structures were elucidated using spectral techniques.