CAROTENOLS AND OXYCAROTENOLR OF THE C40 SERIES 569 



elozanthin,' isolated from the leav'es of Anacharis canadensis (flowering 

 Canada waterweed),^^' is apparently isomeric with flavoxanthin.''*^ Of 

 the mixed pigments from the buttercup, the principal component is lutein, 

 while flavoxanthin, taraxanthin, possibly violaxanthin, and another un- 

 known pigment comprise the rest of the mixture. About one-half of the 

 pigment is combined in ester linkage as a colored fat. 



Chrysanthemaxanthin was first isolated from the winter aster by Karrer 

 and Jucker^**" in 1943. The new phytoxanthin was later isolated by these 

 investigators^''^ from Cijtimis scoparhis (Scotch broom) for further study. 

 The following year it was partially synthesized and its structure was 

 elucidated as a result of this investigation.^'** 



The stmcture of flavoxanthin, also, has recently been elucidated as a re- 

 sult of its sjTithesis from lutein epoxide by Karrer and Jucker.^^' This 

 transformation was brought about in chloroform. It was found by 

 chromatographic separation that two isomeric products were present — 

 flavoxanthin and chrj^santhemaxanthin. Both possess the same empirical 

 formula, C40H56O3, which is the same as that of lutein epoxide. The struc- 

 tural formula which is considered most probable for these compounds is 

 given here. Strain^^^ found that violaxanthin from leaves of 50 plants rang- 



H5C CHi 



\ / 



C HjC CHj 



/ \ H \ / 



HjC C C CHj CH3 CH3 CH3 C 



H^l I ||hhhIhhhhIhhh1hhh/\ 



'C C HC'C:C'C:C'C:c*C:C'C:C-C:C'C:C'C:C'C OH? 



^ \./\\^/ 1 I .H 



HO^ \/V0 



C C 



CH3 / % / ^OH 



HjC C 



H 



Flavoxanthin or chrysanthemaxanthin 



ing from ferns to angiosperms, and from the pansy {Viola tricolor), yielded 

 flavoxanthin and auroxanthin on treatment wdth acids. 



The properties of flavoxanthin and chrj^santhemaxanthin are summarized 

 in Table 7. 



The identity of the synthetic products with the corresponding pigments 



isolated from natural sources is indicated by their specific rotations. Thus, 



the partially synthetic flavoxanthin was found^*- to have a specific rotation 



of 180-190°C., which agrees with a value of 190°C. reported by Kuhn and 



Brockmann^^^ for the natural product. The latter workers isolated 1 10 mg. 



of ciTide flavoxanthin from one kilogram of dried petals of the buttercup 



{Ranunculus acris), from which 40 mg. of pure pigment were prepared. -^^ 



The partially synthetic and the natural chrysanthemaxanthin had similar 



optical rotations which could not be differentiated from that of flavoxan- 

 thin. ^^2 



3** G. MacKinney, Ann. Rev. Biochem., 9, 459-490 (1940). 

 3« H. H. Strain, /. Am. Chem. Soc, 70, 1672 (1948). 



