Chemical Evaluation of Betula Species in Japan. II. Constituents of Betula platyphylla var. japonica

摘要

The constituents of Betula platyphylla var. japonica were identified as follows: Fresh leaves: 12-0-acetyl-3-0-malonylbetulafolienetriol, 12-0-acetyl-3-O-malonylbetulafolienetriol oxide I (= papyriferic acid), 12-0-acetyl-betulafolienediolone, hydroxyhopanone, caryophyllene oxide, kaempferol 3-β-(4-O-acetyl)-β-L-rhamnopyran-oside, quercetin 3-O-(4-0-acetyl)-a-L-rhamnopyranoside. Outer bark: betulin, lupeol, betulinic acid, betulonc, betulin 3-O-caffeate, oleanolic acid, oleanolic acid 3-O-acetate. Inner bark: (-)-catechin, (-)-catechin 7-0-β-D-xylopyranoside, rhododcndrin (= betuloside), aceroside VII, aceroside VIII, l,7-bis[4-hydroxyphenyl]-3-hepten-5-one, 2-hydroxy-l,7-bis[4-hydroxyphenyl]-3-hepten-5-one, acerogenin E, (3β)-3,5'-dihydroxy-4'-methoxy-3',4"-oxo-l,7-diphenyl-l-heptene, 7a-hydroxy-β-sitosterol, 7N-hydroxy-^-sitosterol. Root bark: dammarenediol II 3-O- β-coumarate*, dammarenediol II 3-0-caffeate, ocotillol II 3-O-caffeate*, stigmast-4-cne-3-one. Spikes: caryo-phyllene oxide, (-)-rhododendrol (=betuligenol), 12-O-acetylbetulafolienetriol. The compounds with an asterisk are new.