Two new triterpenes from Alstonia scholaris flowers

In the context of our previous communication on phytochemical studies of the ethanolic extract of flowers of Alstonia scholaris of Pakistan origin, these have resulted in the isolation of two new triterpenoids. One is of the oleanane type, alstoprenyol, 3-β-hydroxy-28-β-acetoxy-5-olea triterpene (1), the other is of ursane type, alstoprenylene 3β-acetate-24-nor-urs-4,12,2'-triene ester triterpene (2) and together with four known triterpenes, α-amyrin acetate (3), α-amyrin (4), lupeol acetate (5) and 3β-hydroxy-24-nor-urs-4,12,28-triene triterpene (6) were isolated. The structures of 1-6 were elucidated with the aid of extensive NMR spectroscopic studies.