21β-Hydroxy-oleanane-type triterpenes from Hippocratea excelsa

Six 21β-hydroxy pentacyclic triterpenes, five oleanane and one ursane types were isolated from Hippocratea excelsa, in addition to the known 3α,21β-dihydroxy-olean-12-ene (1). Their structures were elucidated on the basis of spectroscopic analyses, including homo- and heteronuclear NMR experiments (COSY, ROESY, HSQC and HMBC) and comparison with literature data. Compounds 2-5 were assayed against Giardia intestinalis, but did not show antiprotozoal activity.