Chemical evaluation of Betula species in Japan. V. Constituents of Betula ovalifolia

Abstract

Two new seco-dammarane-type triterpenes, called ovalifoliolides A and B, were isolated from the methanol extract of fresh leaves of Betula ovalifolia together with 12-O-acetylbetulafolienetriol, (3R)-3,5'-dihydroxy-4'-methoxy- 3',4-oxo-1,7-diphenyl-1-heptene and rutin. Betulin, betulin 3-caffeate, rhododendrin, (+)-catechin, (+)-catechin 7-O-β-D-xylopyranoside and procyanidin B-3 were also isolated from the bark. Their structures were determined by spectral data and chemical evidence.