“…The structure of 1 was confirmed as a tirucallane triterpenoid, from the comparison of its optical rotation with that reported for related 3a-OH tirucallanes, euphanes, and lanostanes, which is positive in euphane and lanostane series, and negative in tirucallanes (Keller et al, 1996;Lin et al, 1997;Rö secke and König, 1999;Mishra et al, 2000). Compound 1 showed a ½a 25 D À 10:7 , identical to the one reported for the synthetic methyl ester derivative of a-elemolic acid (3a-hydroxy-tirucalla-8,24-dien-21-oic acid), previously isolated from several Burseraceae (Cotterrell et al, 1970;Billet et al, 1971;Pardhy and Bhattacharya, 1978;Tessier et al, 1982;Sawadogo et al, 1985;Lima et al, 2004;Usubillaga et al, 2004). Based on this evidence, the structure of 1 was confirmed as methyl 3a-hydroxy-tirucalla-8,24-dien-21-oate, whose spectroscopic data is here reported for the first time.…”