Antioxidant activities of phycocyanobilin prepared from Spirulina platensis

The antioxidative activity of phycocyanobilin from Spirulina platensis was evaluated against oxidation of methyl linoleate in a hydrophobic system or with phosphatidylcholine liposomes. Phycocyanobilin as well as phytochemicals including alpha -tocopherol, caffeic acid and zeaxanthin, effectively inhibited the peroxidation of methyl linoleate and produced a prolonged induction period. Oxidation of phosphatidylcholine liposomes was also controlled markedly by adding phycocyanobilin or alpha -tocopherol. Phycocyanobilin was distributed outside in the liposomes to scavenge radicals from AAPH and to prevent initiation of radical chain reactions. When the concentrations of phycocyanin and phycocyanobilin in the reaction mixture were adjusted equally on a phycocyanobilin basis, the activity of phycocyanobilin was almost the same as that of phycocyanin in the AAPH-containing reaction mixture. The antioxidizing action of phycocyanin prepared from spray-dried Spirulina almost agreed with that from fresh Spirulina in the AAPH-containing reaction mixture. These results suggest that phycocyanobilin is responsible for the majority of the antioxidative activity of phycocyanin and may act as an effective antioxidant in a living human body.