Two lignan rhamnosides from birch leaves

Abstract

The extractives of shirakamba (Betula platyphylla Sukatchev var. japonica Hara) leaves were investigated. Two lignan glycosides were isolated, and their structures were elucidated to be 1-(4′-hydroxy-3′-methoxyphenyl)-2-[1″-(3-α-L- rhamnopyranosyloxypropyl)-3″-hydroxyphenoxy]-1,3-propanediol (I) and a new 2,3-dihydro-2-aryl-benzofuran configuration neolignan, cis-2,3-dihydro-2-(4′-α-L-rhamnopyranosyloxy-3′-methoxyphenyl) -3-hydroxymethyl-7-hydroxy-5-benzofuranpropanol (II). These neolignan rhamnosides were newly found in shirakamba. © The Japan Wood Research Society 1999.