Abstract. Objective: Phycocyanin is a pigment found in
blue-green algae which contains open chain tetrapyrroles
with possible scavenging properties. We have studied its
antioxidant properties.
Materials and methods: Phycocyanin was evaluated as a
putative antioxidant in vitro by using: a) luminol-enhanced
chemiluminescence (LCL) generated by three different
radical species (O¹
2 , OH·, RO·) and by zymosan activated
human polymorphonuclear leukocytes (PMNLs), b) deoxyribose
assay and c) inhibition of liver microsomal lipid
peroxidation induced by Feþ2-ascorbic acid. The antioxidant
activity was also assayed in vivo in glucose oxidase
(GO)-induced inflammation in mouse paw.
Results: The results indicated that phycocyanin is able to scavenge
OH· (IC50 ¼ 0:91 mg/mL) and RO· (IC50 ¼ 76mg/mL)
radicals, with activity equivalent to 0.125mg/mL of
dimethyl sulphoxide (DMSO) and 0.038mg/mL of trolox,
specific scavengers of those radicals respectively. In the
deoxyribose assay the second-order rate constant was 3:56 ´
1011 M¹1 S¹1, similar to that obtained for some non-steroidal
anti-inflammatory drugs. Phycocyanin also inhibits liver
microsomal lipid peroxidation (IC50 ¼ 12 mg/mL), the CL
response of PMNLs (p < 0.05) as well as the edema index in
GO-induced inflammation in mouse paw (p < 0.05).
Conclusions: To our knowledge this is the first report
of the antioxidant and anti-inflammatory properties of
c-phycocyanin.