ANTIBACTERIAL TRITERPENOIDS FROM DILLENIA-PAPUANA AND THEIR STRUCTURE-ACTIVITY-RELATIONSHIPS

Two new oleanene-type triterpenoids, dillenic acids D and E, have been isolated from the leaves and stems of Dillenia papuana together with the new natural product 3-oxoolean-12-en-30-oic acid. Together with th ese compounds, the known compound, betulinic acid (3 beta-hydroxy-20(2 9)-lupen-28-oic acid) was isolated as the major component of the fract ions studied. Dillenic acids D and E were characterized as 2,3-seco-2- oxoolean- 12-en-3-methylester-30-oic acid and 1 alpha,3 beta-dihydroxy olean-12-en-30-oic acid and their nuclear magnetic resonance data were unambiguously assigned using two-dimensional nuclear magnetic resonan ce techniques. A comparison of antibacterial activities of these compo unds with the earlier reported dillenic acids A-C indicated that, asid e from a double bond in gamma- or delta-position to a carboxylic group , a ketone function in ring A of an oleanene-skeleton may be required for the observed activity.