Chemical investigation of the dichloromethane extract of the resin from the bark of Canarium asperum led to the isolation of a mixture of new triterpene diastereomers, asperol a (1a) and asperol b (1b) in a 3:2 ratio. The structures of 1a and 1b were elucidated by extensive 1D and 2D NMR spectroscopy and confirmed by mass spectrometry. β-amyrin and α-amyrin were also obtained as the major constituents of the resin.
