10.22376/ijpbs.2019.10.1.p1-12 Volume 5 Issue 3 2014 (July- September) Oleanan derivative compound namely 3-acetyl-12-oleanen-28-oic acid, has been isolated from n-hexane fraction of the bark lessThan i greaterThan M. umbellate lessThan /i greaterThan (Houtt) Stapf var. degrabrata The molecular structure was determined by IR spectroscopy, NMR 1D and 2D ( lessThan sup greaterThan 1 lessThan /sup greaterThan H-NMR, lessThan sup greaterThan 13 lessThan /sup greaterThan C-NMR, DEPT, COSY, HMQC and HMBC). The results of test bioactivity to hexane, chloroform, ethyl acetic, methanol extracts and compound 1 mentioned above showed that they are toxic to lessThan i greaterThan A. salina lessThan /i greaterThan (brine shrimp) with LC lessThan sub greaterThan 50 lessThan /sub greaterThan 361.93 to 460 µg/mL lessThan b greaterThan . lessThan /b greaterThan The most toxic one was the compound 1 with the LC lessThan sub greaterThan 50 lessThan /sub greaterThan value of 361.93 µg/mL. At a concentration of 1000 µg/mL, the extract of hexane, methanol and compound 1 showed very high inhibition to the growth of lessThan i greaterThan B. subtilis lessThan /i greaterThan and lessThan i greaterThan C.albican lessThan /i greaterThan , whereas the extract of ethyl acetate had very high inhibition effect to the growth of lessThan i greaterThan S. aureus lessThan /i greaterThan and lessThan i greaterThan A. niger lessThan /i greaterThan lessThan b greaterThan . lessThan /b greaterThan The inhibition zone of the three extracts and compound 1 were greater than 14 mm. On the other hand, the extracts of chloroform gave weak inhibition against bacteria and fungi. USMAN, NUNUK HARIANI SOEKAMTO, HANAPI USMAN AND AHYAR AHMAD M. umbellate, toxicity and antimicrobial activity, 3-acetyl-12-oleanen-28-oic acid. 231-238