Identification of triterpenes from milkweed (Asclepias syriaca)

The chloroform extract of Asclepias syriaca stem were investigated. Three triterpenes were isolated by TLC, VLC, and preparative chromatography, and their structures established by one and two-dimensional NMR spectroscopy. Lupenyl acetate has been isolated for the first time from A. syriaca; this is thefirst representative of a triterpene bearing a lupane skeleton in this species. In addition, alpha-amyrin acetate and alpha-amyrin butyrate were isolated.