Comparative Antiproliferative Action of Two Extracts from Tilia x viridis on Normal and Tumoral Lymphocytes: Rela-tionship with Antioxidant Activity

Tilia species have been used in Asia, Europe and in America to treat anxiety and also for the treatment of colds and inflammation. The oxygen reactive species (ROS) (hydrogen peroxide (H2O2) and the superoxide anion (O2) are involve in the balance cell proliferation/death in lymphocytes. It was reported the presence of flavonoids in Tilia species which possess antioxidant properties. The aim of this study was to determine comparatively the effect of an aqueous (AE) and ethanol (E) extract from Tilia x viridis, on the proliferation of tumoral and normal concanavalin A stimulated murine lymphocytes in relation to antioxidant activities such as peroxidase (Px), catalase (CAT) and superoxide dismutase (SOD) activities involves in H2O2 modulation. Also a phytochemical pattern of the two extracts in relation to flavonoids content was determined. Both extracts presented antiproliferative action on both type of lymphocytes but E was more selective on the tumoral lymphocytes inhibition (EC50 (μg/ml, Mean ±SEM) (tumoral): 50 ± 4; EC50; (normal lymphocytes): 323 ± 20); this action was related to a high polyphenols content (150 ± 10 mg/g extract) and high “per se” SOD and low Px activities. In conclusion, the extracts could be a source of antioxidant compounds which contribute to a selective antiproliferative action on tumoral cells, acting through the modulation of H2O2 levels.