Composition and chemical variability of the triterpene fraction of dichloromethane extracts of cork (Quercus suber L.)

Abstract Dichloromethane extracts were prepared from 38 samples of cork harvested in different locations of Corsica and Sardinia from individual trees of Quercus suber L. Friedelin, 3-α-hydroxyfriedelan-2-one, betulin, betulinic acid, β-sitosterol and sitost-4-en-3-one were identified and their molar percentages were calculated by 13C NMR spectroscopy, following a procedure recently developed by our group. The results were submitted to chemometric analysis (k-means and principal component analysis), which allowed three groups to be distinguished with respect to the content of friedelin, betulinic acid and 3-α-hydroxyfriedelan-2-one.