OAROTENOLR AND OXYCAROTENOLS OF THE C40 SERIES 5G1 



Lutein epoxide has been identified as a component of the pigment of the 

 yellow flower, goat's beard {Tragopogon pratensis) ,^°^ as well as of the blos- 

 soms of the winter aster. ^™ This had earlier been mistaken for taraxan- 

 thin.^"'' This epoxide was also found in small amounts in the stinging 

 nettle {Urticn dioicn). Wove recently the Karrer group have noted the 

 occurrence of the mono-ei^oxide of lutein in the following wide variety of 

 flowers: Arnica mont<iiia (mountain arnica)-*"^; Lotus cornicidatus, birdsfoot 

 trefoil (deervetch), or babies' slippers^"^; Cytisus scoparius (Scotch 

 broom) ^""j Ranunculus acris (buttercup)'"*; Trolb'us europaeus (globe- 

 flower)'"^; Lahurnum anagyroides (golden chain) '"^; Kerria japonica, 

 pleni flora (double Japanese kerria)'"'; and Anacharis canadensis (Canada 

 water weed, elodea).^^"-^^' The occurrence of the epoxide in green and 

 etiolated leaves has been indicated by the recent report of Karrer et al.^"^"^ 

 The pigment prepared by Hey^-' from Anacharis canadensis in 1937 and 

 named "eloxanthin" has been shown to be lutein epoxide. ^^" 



(c) a-Citraurin, C3oH4n02. On oxidation of lutein with potassium per- 

 manganate, the /3-ionone ring is destroyed and an aldehyde originates. 

 This derivative stands in the same relationship to /3-citraurin as Q:-apo-2- 

 carotenal does to i8-apo-2-carotenal. a-Citraurin can be crystallized from 

 methanol in glistening oiange platelets which melt at 153°C. When it is 

 acted on by hydroxylamine acetate, an oxime results which forms clusters 

 of needles and Avhich melts at 148°C. 



HjC CHj 



Q CHj CH5 CH3 CH 5 



/\hhh|hhhIhhhhIhhhI yP 

 HjC C'C:c-c:C'C:c-c:C'C:C-C:C-C:C-C:C- C-H 



H. I I 



HO 



c c 



/ \ ^ \ 



C CH- 



H 



ct-Citraurin 



(rf) Perhydrolutein, C40H78O2. On catalytic reduction of lutein, the 

 perhydrolutein originates as a thick, colorless oil which is weakly dextro- 

 rotatory ([q;]d CHCI3 — +28°).^^^ It is more easily soluble in organic 

 solvents than is lutein. It is readily esterified to an oily diacetate.^^^ 



(5) Zeaxanthin 



Thudichum^^ first recognized that the pigment present in yellow corn 

 {Zea mays) belonged to the group of carotenoids. Palmer and Eckles,^-^ 

 who carried out much of the early work on this substance, assumed that the 



320 p. Karrer and J. Rutschmann, Helv. Chim. Acta, 28, 1526-1527 (1945). 



321 D. Hey, Btochem. J., 31, 532-534 (1937). 



322 P. Karrer, E. Krause-Voith, and K. Steinlin, Helv. Chim. Acta, 31, 113-120 (1948). 



323 L. S. Palmer and C. H. Eckles, J. Biol. Chem.. 17, 191-210 (1914). 



