In vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin from selenium-enriched Spirulina platensis.
Both selenium and phycocyanin have been reported to show potent cancer chemopreventive activities. In this study, we investigated the in vitro antioxidant and antiproliferative activities of selenium-containing phycocyanin (Se-PC) purified from selenium-enriched Spirulina platensis. The antioxidant activity of Se-PC was evaluated by using four different free radical scavenging assays, namely, the 2,2'-azinobis-3-ethylbenzothiazolin-6-sulfonic acid (ABTS) assay, 1,1-diphenyl-2-picryhydrazyl (DPPH) assay, superoxide anion scavenging assay, and erythrocyte hemolysis assay. The results indicated that Se-PC exhibited stronger antioxidant activity than phycocyanin by scavenging ABTS, DPPH, superoxide anion, and 2,2'-azobis-(2-amidinopropane)dihydrochloride free radicals. Se-PC also showed dose-dependent protective effects on erythrocytes against H 2O 2-induced oxidative DNA damage as evaluated by the Comet assay. Moreover, Se-PC was identified as a potent antiproliferative agent against human melanoma A375 cells and human breast adenocarcinoma MCF-7 cells. Induction of apoptosis in both A375 and MCF-7 cells by Se-PC was evidenced by accumulation of sub-G1 cell populations, DNA fragmentation, and nuclear condensation. Further investigation on intracellular mechanisms indicated that depletion of mitochondrial membrane potential (DeltaPsi m) was involved in Se-PC-induced cell apoptosis. Our findings suggest that Se-PC is a promising organic Se species with potential applications in cancer chemoprevention.
Chen
Tianfeng
T
Research Laboratory for Food Protein Production and Food and Nutritional Sciences Programme, Department of Biology, The Chinese University of Hong Kong, Hong Kong SAR, China.
Wong
Yum-Shing
YS
D000230:Adenocarcinoma; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects*; D045744:Cell Line, Tumor; D016166:Free Radical Scavengers / Q000494:pharmacology; D006801:Humans; D008545:Melanoma; D010798:Phycocyanin / Q000737:chemistry / Q000494:pharmacology*; D012643:Selenium / Q000008:administration & dosage / Q000032:analysis*; D053545:Spirulina / Q000737:chemistry*
D000975:Antioxidants; D016166:Free Radical Scavengers; D010798:Phycocyanin; D012643:Selenium