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Antioxidative Activities of Algal Keto Carotenoids Acting as Antioxidative Protectants in the Chloroplast
Author(s) -
Dambeck Michael,
Sandmann Gerhard
Publication year - 2014
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/php.12249
Subject(s) - fucoxanthin , phaeodactylum tricornutum , astaxanthin , carotenoid , haematococcus pluvialis , biochemistry , phytoene desaturase , xanthophyll , lipid peroxidation , chemistry , chloroplast , photosynthesis , photoprotection , fatty acid , antioxidant , biology , algae , botany , biosynthesis , enzyme , gene
Very diverse carotenoid structures exist in the photosynthesis apparatus of different algae. Among them, the keto derivatives are regarded the most antioxidative. Therefore, four different keto carotenoids, peridinin, fucoxanthin, siphonaxanthin and astaxanthin fatty acid monoesters, were isolated and purified from Amphidinium carterae , Phaeodactylum tricornutum, Caulerpa taxifolia and Haematococcus pluvialis , respectively. The carotenoids were assayed as inhibitors of photosensitizer initiated reactions or scavengers of radicals in the early events generating reactive oxygen species as starters for peroxidation and as protectants against the whole reaction chain finally leading to lipid peroxidation. These in vitro studies demonstrated the substantial antioxidative properties as indicated by the IC 50 values of all four keto carotenoids with superior protection by astaxanthin fatty acid monoesters which were as effective as free astaxanthin and of peridinin against radicals. As an example, the in vivo relevance of fucoxanthin for protection of photosynthesis from excess light and from peroxidative agents was evaluated with intact cells. Cultures of P. tricornutum with decreased fucoxanthin content generated by inhibitor treatment were exposed to strong light or cumene hydroperoxyde. In each case, oxidation of chlorophyll as marker for damaging of the photosynthesis apparatus was less severe when the fucoxanthin was at maximum level.