Identification and quantification of betulinic acid

Betulinic acid was identified in the bark and in the wood of Platanus aceri folia (plane) and of Betula pendula (white birch) by thin layer chromatogra phy, gas chromatography (GC), GC coupled with mass spectrometry (MS), elect rospray ionisation MS, and H-1-nuclear magnetic resonance spectroscopy. Qua ntitative analysis by GC after derivatisation under mild silylating conditi ons and using squalane as internal standard showed 3.3% betulinic acid in t he cork of plane while the wood content was much lower, The bark of white b irch contained 0.3% betulinic acid. Copyright (C) 1999 John Wiley & Sons, L td.