Chemical evaluation of Betula species in Japan. II. Constituents of Betula platyphylla var. japonica

Abstract

The constituents of Betula platyphylla var. japonica were identified as follows: Fresh leaves: 12-O-acetyl-3-O-malonylbetulafolienetriol, 12-O- acetyl-3-O-malonylbetulafolienetriol oxide I (=papyriferic acid), 12-O- acetyl-betulafolienediolone, hydroxyhopanone, caryophyllene oxide, kaempferol 3-O-(4-O-acetyl)-α-L-rhamnopyranoside*, quercetin 3-O-(4-O-acetyl)-α-L- rhamnopyranoside. Outer bark: betulin, lupeol, betulinic acid, betulone, betulin 3-O-caffeate, oleanolic acid, oleanolic acid 3-O-acetate. Inner bark: (-)-catechin, (-)-catechin 7-O-β-D-xylopyranoside, rhododendrin (=betuloside), aceroside VII, aceroside VIII, 1,7-bis[4-hydroxyphenyl]-3- hepten-5-one, 2-hydroxy-1,7-bis[4-hydroxyphenyl]-3-hepten-5-one*, acerogenin E, (3R)-3,5'-dihydroxy-4'-methoxy-3',4''-oxo-1,7-diphenyl-1-heptene*, 7α- hydroxy-β-sitosterol, 7β-hydroxy-β-sitosterol. Root bark: dammarenediol II 3-O-p-coumarate*, dammarenediol II 3-O-caffeate, ocotillol II 3-O- caffeate*, stigmast-4-ene-3-one. Spikes: caryophyllene oxide, (-)- rhododendrol (=betuligenol), 12-O-acetylbetulafolienetriol. The compounds with an asterisk are new.