Astaxanthin and peridinin inhibit oxidative damage in Fe2+-loaded liposomes: Scavenging oxyradicals or changing membrane permeability?

Astaxanthin and peridinin, two typical carotenoids of marine microalgae, an d lycopene were incorporated in phosphatidylcholine multilamellar liposomes and tested as inhibitors of lipid oxidation. Contrarily to peridinin resul ts, astaxanthin strongly reduced lipid damage when the lipoperoxidation pro moters-H2O2, tert-butyl hydroperoxide (t-ButOOH) or ascorbate and Fe2+:EDTA were added simultaneously to the liposomes. In order to check if the antio xidant activity of carotenoids was also related to their effect on membrane permeability, the peroxidation processes were initiated by adding the prom oters to Fe2+-loaded liposomes (encapsulated in the inner aqueous solution) . Despite that the rigidifying effect of carotenoids in membranes was not d irectly measured here, peridinin probably has decreased membrane permeabili ty to initiators (t-ButOOH > ascorbate > H2O2) since its incorporation limi ted oxidative damage on iron-liposomes. On the other hand, the antioxidant activity of astaxanthin in iron-containing vesicles might be derived from i ts known rigidifying effect and the inherent scavenging ability. (C) 2001 A cademic Press.