Xanthophylls in light harvesting complexes perform a number of functions ranging from structural support to light-harvesting and photoprotection. In the major light harvesting complex of photosystem II in plants (LHCII), the innermost xanthophyll binding pockets are occupied by lutein molecules. The conservation of these sites within the LHC protein family suggests their importance in LHCII functionality. In the present work, we induced the photoprotective switch in LHCII isolated from the Arabidopsis mutant npq1lut2, where the lutein molecules are exchanged with violaxanthin. Despite the differences in the energetics of the pigments and the impairment of chlorophyll fluorescence quenching in vivo, we show that isolated complexes containing violaxanthin are still able to induce the quenching switch to a similar extent to wild type LHCII monomers. Moreover, the same spectroscopic changes take place, which suggest the involvement of the terminal emitter site (L1) in energy dissipation in both complexes. These results indicate the robust nature of the L1 xanthophyll binding domain in LHCII, where protein structural cues are the major determinant of the function of the bound carotenoid.
The aim of this study was to characterize carotenoids and flavonoids present in French marigold flowers (Tagetes patula "Durango Red") as well as to assess the effects of harvest dates and postharvest treatments on these compounds. Carotenoids and flavonoids were quantified using their respective standards or semiquantified using relevant related standards. Lutein and its derivatives largely dominated the flower carotenoids, while the flavonoids were diverse with patuletin leading the list. Of the different postharvest treatments, ensilage leads to the highest content of carotenoids (from 5.0 to 7.8 g kg-1 dw) and flavonoids (from 19 to 50 g kg-1 dw). The composition of individual flavonoids was greatly influenced by different postharvest treatments, while the influence of harvest dates was secondary. Ensilage and drying induced separate metabolic pathways leading to degradation of high-molecular glycosidic compounds, converting the compounds either to their aglycones or into the intermediate flavonoid glycosides. We conclude that according to the intended industrial application, different postharvest techniques can be employed to acquire desired flavonoids on a large scale.
- MeSH
- časové faktory MeSH
- flavonoidy chemie metabolismus MeSH
- karotenoidy chemie metabolismus MeSH
- květy chemie růst a vývoj metabolismus MeSH
- lutein chemie metabolismus MeSH
- rostlinné extrakty chemie metabolismus MeSH
- Tagetes chemie růst a vývoj metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
Karotenoidy jsou významnými přírodními antioxidanty, jedním z nich je ilutein. Obsahuje ve své struktuře hydroxylové skupiny, díky nimž i efektivněji vychytávat voiné radikály a realďivní formy kyslíku. Absorbuje také vysoce energetické modré záření. Tyto vlastnosti jsou důležité pro jeho působení v oku. V žluté skvrně působí proti vzniku a rozvoji věkem podmíněné makulámí degenerace. Oční čočka je místem ochrany před šedým zákalem. Může přispívat ochraně před kardiovaskulárními chorobami, a to především ovlivněním vlastnosti epitelu a svou antioxidační aktivitou. Působí jako prevence některých typů rakoviny. In vitro byla prokázána jeho schopnost inhibovat transkripci genů viru hepatitidy typu B.
Carotenoids are important natural antioxidants. Lutein is one of them. There are hydroxyl groups in its structure and these enable lutein to scavenger free radicals and reactive oxygen species more effectively than other carotenoids. Lutein also absorbs high energy blue light. These properties play critical role in the eye. In macula lutea lutein prevents age-related macular degeneration and in lens it probably prevents formation of cataract. Lutein can also help in fight with cardiovaskular diseases, mainly due to its antioxidant properties and is also able to change the proterties of epithelial cells. Lutein was also found as an anticancerogenic agent. In vitro it is able to inhibit transcription of the hepatitis B virus genes.
- Klíčová slova
- xantofyly, věkem podmíněná makulární degenerace, rakovina, kardiovaskulární onemocnění, virus hepatitidy typu B,
- MeSH
- antikarcinogenní látky MeSH
- antioxidancia chemie MeSH
- kardiovaskulární nemoci prevence a kontrola MeSH
- karotenoidy farmakologie fyziologie chemie MeSH
- lidé MeSH
- lutein fyziologie chemie MeSH
- makulární degenerace prevence a kontrola MeSH
- virus hepatitidy B účinky léků MeSH
- xanthofyly farmakologie fyziologie chemie MeSH
- Check Tag
- lidé MeSH
