Abstract
Eight triterpenoids and a sterol were isolated from the bark of Pieris japonica D. DON (Japanese name : asebi, Ericaceae) and have been elucidated as 3β-acetoxyurs-11-en-28, 13-olide, 3β-acetoxy-12α-hydroxyolean-28, 13-olide, 3β-acetoxy-28-hydroxyurs-12-ene, 3β, 28-dihydroxyurs-12-ene, 3β-acetoxyurs-12-en-28-al, taraxeryl acetate, taraxerol, taraxerone and β-sitosterone by a combination of chemical and spectroscopic studies. 13C Nuclear magnetic resonance spectral analysis of several γ-lactones of the ursane and oleanane series was undertaken, and all the carbons were assigned by means of single frequency off-resonance and selective decoupling methods and by comparison of the signals with those of methyl esters of acetyl ursolic acid and acetyl oleanolic acid.
