RESUMO
The antioxidant activity of methanolic extracts derived from shoots (HR-shoots) and roots (HR-roots) of pRi-transformed Rehmannia glutinosa plants were determined. The activity was indicated by the ability of the plant extracts to inhibit superoxide anion (O2(-·)) generation and thiobarbituric acid reactive substances (TBARS) production in resting blood platelets and platelets activated by thrombin. The strongest activity was exhibited by the HR-shoot extract (50 µg/mL). The present study also examines the antioxidant properties of the plant extracts against human plasma lipid peroxidation induced by strong biological oxidants: hydrogen peroxide (H2O2) and H2O2/Fe. The study shows that extracts from transformed R. glutinosa plants may be a promising source of natural antioxidants, which would be valuable in various cardiovascular diseases. The extracts may also protect lipids against oxidative modifications.