Secondary metabolites from the wood bark of Durio zibethinus and Durio kutejensis.

Phytochemical exploration of a wood bark extract from Durio zibethinus afforded two new triterpenoids, namely, methyl 27-O-trans-caffeoylcylicodiscate (1) and methyl 27-O-cis-caffeoylcylicodiscate (2), a new phenolic, 1,2-diarylpropane-3-ol (3), and seven known compounds, fraxidin, eucryphin, boehmenan, threo-carolignan E, (-)-(3R,4S)-4-hydroxymellein, methyl protocatechuate, and (+)-(R)-de-O-methyllasiodiplodin (4). In addition, chemical analysis of a wood bark extract from Durio kutejensis yielded the new triterpenes 3beta-O-trans-caffeoyl-2alpha-hydroxyolean-12-en-28-oic acid (5) and 3beta-O-trans-caffeoyl-2alpha-hydroxytaraxest-12-en-28-oic acid (6) together with four known compounds, maslinic acid, arjunolic acid, 2,6-dimethoxy-p-benzoquinone, and fraxidin. The structures of all compounds were determined on the basis of spectroscopic data.