Triterpenoids and Sterols from the Stem of Alnus Formosana Burk

Abstract

The chemical constituents of the stem of Alnus formosana Burk. were investigated and sixteen known compounds, composed of eleven triterpenoids and five sterols, were isolated and characterized from the n-hexane- and chloroform-soluble fractions of the methanol extract. Of these, seven triterpenoids, lupeol, lupenone, betulinic acid, 3-O-acetylbetulinic acid, 3-O-acetylerythrodiol, 3-O-acetyloleanolic aldehyde, and taraxerone, were isolated for the first time from an Alnus species. The isolation of the five sterols, stigmastanone, stigmast-4-en-3-one, β-sitosterol, β-sitosteryl-β-D-glucoside, and stigmasta-3,6-dione, is also the first time that the presence of such natural products has been recorded for an Alnus species. Taraxerone and betulinic acid were the major non-polar constituents of the stem of A. formosana.