In this work we investigate the antioxidant properties of an aqueous extrac
t prepared from an infusion of Ilex paraguariensis (Aquifoliaceae) using fr
ee radical-generating systems. The extract inhibited the enzymatic and none
nzymatic lipid peroxidation in rat liver microsomes in a concentration-depe
ndent fashion, with IC50 values of 18 mu g/ml and 28 mu g/ml, respectively.
The extract also inhibited the H2O2-induced peroxidation of red blood cell
membranes with an IC50 of 100 mu g/ml and exhibited radical scavenging pro
perties toward superoxide anion (IC50 = 15 mu g/ml) and 2,2-diphenyl-1-picr
ylhydrazyl radical. In the range of concentrations used, the extract was no
t a scavenger of the hydroxyl radical. Our results suggest that ingestion o
f extracts of Ilex paraguariensis could contribute to increase the antioxid
ant defense of an organism against free radicals attack. (C) 2000 Academic
Press.