[Show abstract][Hide abstract] ABSTRACT: The complete characterization of two compounds obtained from the acetoneextract of Populus tremula knotwood has been was achieved using LC-DAD-MS,MS/MS, IR and NMR. The new compounds were unequivocally identified as a mixtureof the ester isomers of the (E) and (Z) p-coumarate of 1-O-rutinose. The isomers showedthe capacity to inhibit lipid peroxidation induced by tert-butylhydroperoxide and to trapperoxyl radicals, as determined by a chemiluminescence method. These new phenyldisaccharides also showed a significant ORAC (oxygen radical absorbance capacity)value, i.e. 11.7 ÃŽÂ¼M TE (Trolox Equivalents).