Antioxidant effects of Ilex paraguariensis: induction of decreased oxidability of human LDL in vivo.

We have recently demonstrated that Ilex paraguariensis extracts inhibit LDL oxidation in vitro exhibiting a potency comparable to that of ascorbic acid (Gugliucci, A. and Stahl, A.J.C. 1995; Biochem Mol Biol Int 35, 47-56). In the present work we extend our observations to the in vivo situation. We first examined the oxidability of LDL in whole plasma from healthy fasted human subjects before and after intake of Ilex paraguariensis. Intake of water extracts of Ilex paraguariensis inhibit copper-induced autoxidation of LDL in whole plasma as shown by the end-term production of TBARS, and as a consequence are able to impair the appearance of Schiff base induced fluorescence, higher electrophoretic mobility and fragmentation of apoB. When LDL was isolated from plasma prior to oxidation no significant differences in lag-time, slope or maximum rate of oxidation could be detected. We then conclude that antioxidants in Ilex paraguariensis are absorbed and reach sufficient high levels in plasma to inhibit copper-induced LDL autoxidation by increasing aqueous-phase antioxidant capacity.