The role of dietary chlorophylls: an EPR study on the antioxidant activities of tomato lipid extracts

Identification of the components responsible for the antioxidant activity of lipid extracts from tomato with some lipid antioxidants was obtained by EPR using the stable free radical 1,1-diphenyl-2-picrylhydrazyl (DPPH). Lipid extracts were obtained from leaves, roots and berries of tomato grown in hydroponics. Both fast lipophilic antioxidants (FLA) and slow lipophilic antioxidants (SLA) were present in leaves and berries whereas only SLA could be identified in the root lipid extract. Simulation of the decay kinetic of DPPH by leaves was obtained with a chlorophyll b/beta-carotene mixture whereas lycopene, which reduced DPPH with a stoichiometry 1:1, behaved as a SLA. Antioxidant activity of lipid extract from leaves showed values 56- and 45-fold higher than the antioxidant activity of lipid extract from root and berries, respectively and it was mainly due to the presence of chlorophyll, representing in the leaf 38% of FLA.