Jarle André Haugan

[20] Isolation of fucoxanthin and peridinin

Publisher Summary This chapter discusses isolation of fucoxanthin and peridinin. The allenic carotenoids fucoxanthin (I) and peridinin (II) are the two carotenoids biosynthesized in largest quantity. Both carotenoids have the same end groups, five chiral centers, and one chiral axis. The structure of the central chain differs, however—fucoxanthin (I) is a C 4o -skeletal carotenoid with an octaenone chromophore whereas peridinin (II) is a C 37 -skeletal butenolide carotenoid. Fucoxanthin (I) is produced de novo with several classes of algae within the Chromophyta, representing major carotenoids in the Chrysophyceae, Prymnesiophyceae, Bacillariophyceae, and Phaeophyceae. The most convenient source is the wild macroalgae of the Phaeophyceae. De novo synthesis of peridinin (II) is restricted to the Dinophyceae, although peridinin (II) is encountered further along the marine food chain. Isolation of peridinin (II) is best effected from wild blooms of dinoflagellates or from dinoflagellates grown in pure culture. There are frequent demands for reference samples of these carotenoids. In this regard, this chapter recommends procedures for their convenient isolation from algae.

Improved isolation procedure for fucoxanthin

Abstract An improved isolation procedure for crystalline fucoxanthin from brown algae is described, involving partition and chromatography. The method is applicable to peridinin. Partition ratios for fucoxanthin and peridinin are reported.

Absolute configurational assignment of 3-hydroxycarotenoids

Attempts were made to develop an exciton chirality method applicable to the unique cases represented by 3-hydroxycarotenoids. However, this approach has so far not been successful. The 3-hydroxy configurations were therefore determined by the extended Mosher 1H-NMR method. Nine carotenoids with seven different end groups and of known 3-hydroxy configurations were derivatized with (R)- and (S)-methoxyphenylacetic acid (MPA); they all gave the expected shift differences. Three other auxiliary reagents with naphthalene and anthracene nuclei gave larger and consistent NMR shift differences, but they are not yet commercially available.

TOTAL SYNTHESIS OF C31-METHYL KETONE APOCAROTENOIDS. PART 4. FIRST TOTAL SYNTHESIS OF (3S,5R,6R)-PARACENTRONE

Optically active (all-E)-(3S,5R,6R)-paracentrone has been prepared by total synthesis for the first time, in 3% overall yield over 13 linear steps from the readily available (4R,6R)-actinol, (2E)-3-methylpent-2-en-4-yn-1-ol, (all-E)-2,7-dimethylocta-2,4,6-triene-1,8-dial and 1,1-dimethoxypropan-2-one. All spectral data for synthetic (all-E)-(3S,5R,6R)-paracentrone are in accordance with data reported for the natural compound.