Abstract: Three compounds were isolated from the bark of Eucalyptus exserta by various column chromatographic techniques.Their structures were identified as 3β-O-trans-coumaroyl-12-en-28-oleanolic acid (1), 3β-O-trans-coumaroyl-12-en-28-ursolic acid (2) and 3-O-methylellagic acid-4′-O-α-L-rhamnopyranoside (3) by 1H-NMR,13C-NMR and MS analyses. Compound 1 was obtained from the family Myrtaceae for the first time, compounds 1 and 2 were isolated from the bark of Eucalyptus species for the first time, compounds 1~3 were isolated from E.exserta for the first time.All the isolated compounds were tested for their molluscicidal activity against Pomacea canaliculata, nematicidal activity against Meloidogyne incognita, and growth inhibition effect against Spodoptera litura cells.The results suggested that all compounds possessed weak molluscicidal activity against P.canaliculata, with mortalities of 20.03%, 22.14% and 9.84% after 72 h, respectively, at a concentration of 50 mg/L. At a concentration of 100 mg/L,compounds 1 and 2 exhibited weak nematicidal activity against M.incognita, with mortalities of 28.12% and 42.19% after 72 h,respectively. Compound 3 exhibited no nematicidal activity against M.incognita. Compounds 1 and 2 showed potent cytotoxic activity against S.litura cells,with inhibition rates of 71.07% and 84.03%,respectively, at a concentration of 20 mg/L. Compound 3 showed weakly activity against S.litura cells,at the same concentration level, with the inhibitory rate of 44.30%.

Key words: Eucalyptus exserta, bark, triterpenoid, ellagic acid, bioactivities