Antioxidant Activity of a Botanical Extract Preparation of Ilex paraguariensis : Prevention of DNA Double-Strand Breaks in Saccharomyces cerevisiae and Human Low-Density Lipoprotein Oxidation

Abstract

We analyzed the antioxidant properties of Ilex paraguariensis infusion (Ip) popularly known as mate (mä′tā), by using two experimental models: the induction of DNA double-strand breaks (DSB) by hydrogen peroxide (H₂O₂) and lethality in Saccharomyces cerevisiae, as well as peroxide and lipoxygenase-induced human low-density lipoprotein (LDL) oxidation. Diploid yeast cells were exposed to different concentrations of H₂O₂ (5-10 mmol/L) in the absence or presence of Ip infusion (10^-1 v/v) or α-tocopherol (10^-2 mol/L). Both mate infusion and α-tocopherol significantly decreased the dose dependent DSB number, and the lethality induced by H₂O₂. Peroxynitrite and lipoxygenase-induced human LDL oxidation are inhibited by Ip extracts in a potent, dose-dependent fashion. Dilutions of 5 × 10^-3 v/v provide 50% ± 10% inhibition. Finally, Ip extracts are potent direct quenchers of the free radical 1,1-diphenyl-2-picrylhydrazyl. Dilutions of 2 × 10^-2 v/v produced quenching of more than 30%, which was comparable to that obtained with 0.5-1 mmol/L α-tocopherol or the quercetin aglycone, respectively. For comparison, total polyphenol content of Ip, green, and black tea (Camelia sinensis) were 6.5 ± 0.8; 1.8 ± 0.5; and 1.13 ± 0.3 mmol of quercetin equivalents per liter, respectively. Their respective free radical quenching activities at dilutions of 1 × 10^-1 v/v were 75% ± 5%; 35% ± 5%; and 2% ± 5%. Ip is thus a rich source of polyphenols and has antioxidant properties comparable to those of green tea which merit further in vivo intervention and cross-sectional studies.