Bioassay-guided fractionation of the hexane extract of the branches of Mitrephora alba led to the isolation of five diterpenoids: ent-8β-hydroxypimar-15-en-18-oic acid, ent-15,16-dihydroxypimar-8(14)-en-18-oic acid, ent-3β-hydroxytrachyloban-18-oic acid, ent-3β-hydroxytrachyloban-18-al and methyl