CAROTENOLS AND OXYCAROTEN'OLS OF THE C40 SERIES 573 



malonic acid. On energetic oxidation with permanganate or chromic acid, 

 4.5 to 7 molecules of acetic acid are formed. On exhaustive hydrogenation, 

 fiicoxanthin loses four oxygen atoms and gives a perhydrocompound^*'' 

 with the composition C4nH780.>. The following structural formula has been 

 proposed by Hcilbron and Phipers,"'''^' but Smith ■'^■' does not believe that the 

 evidence is sufficient to prove the case. 



HjC CHj H,C CH5 



^(~ CH, CH, CH3 CH, C 



/\ hhIhhhIhhhhIhhhIhh /\ 

 HjC 0=C • C : C • C : C • C : C • C : C • C : C • C : C • C : C • C: C • C : C • C = CH? 



H I I/" 



^C H-C-OH HO-C-H C 



H0"-\ \ ^/ \ / ^OH 



C CHi H3C C 



H. H2 



Fucoxanthin (?) 



b. Occurrence. As the name implies, the chief sources of fucoxanthin 

 are the algae. According to Kylin,^^^ fucoxanthin does not occur in all 

 algae (Table 8). The brown algae were shown by Willstatter and Page^^^ 

 to have a considerably higher proportion of fucoxanthin than of carotene 

 or of lutein (Table 9). 



While the chlorophyll of the higher plants consists of both the a and b 

 types, it is associated almost exclusively with carotene and lutein. In the 

 case of the brown algae chlorophyll a is the only form of this pigment 

 present, and the chief carotenoid is fucoxanthin. Moreover, the ratio of 

 green to yellow^ pigments is about 1 : 1 in the brown algae, instead of 3 : 5 as 

 in the higher plants. 



1 1 . Rhodoxanthin 



According to Karrer and Jucker,^^ Monteverde noted a new pigment in 

 the red-brown leaves of Potamogeton natans (floating-leaf pondweed), in 

 1893, which was later found in various conifers by Tswett,^" and which was 

 designated as "thujorhodin." In 1912-1913, the pigment was isolated by 

 Monteverde and Lyubimenko^^^'^^^ in a crystalline state. After studies by 

 Prat^^" and Lippmaa,^"'^^^ Kuhn and Brockmann^^^ isolated 200 mg. of the 



«5 J. H. C. Smith, Ann. Rev. Biochem., 6, 489-512 (1937). 



356 H. Kylin, Z. physiol. Chem., 166, 39-77 (1927). 



55' M. Tswett, Compt. rend., 152, 788-789 (1911). 



^* N. A. Monteverde and V. N. Lyubimenko, Bull. acad. imp. sci. St. Petersburg, VI, 



6, 609-630 (1912); Chein. AbsL, 6, 2092-2093 (1912). Cited by L. Zechmeister, Die 

 Carotinoide, Springer, Berlin, 1934, p. 222. 



^' X. A. Monteverdi and V. N. Lyubimenko, Bull. acad. imp. sci. St. Petersburg, VII, 



7, 1105-1124 (1913); Chem. AbsL, 8, 913 (1914). Cited by L. Zechmeister, Die Carotin- 

 oide, p. 222, and by P. Karrer and E. Jucker, Carotinoide, p. 246. 



»«» S. Prdt, Biochem. Z., 152, 495-497 (1924). 



3«i T. Lippmaa, Compt. rend., 182, 867-868 (1926). 



'«2T. Lippmaa, Co7npt. rend., 182, 1040-1042 (1926). 



s"' R. Kuhn and H. Brockmann, Per., 66, 828-841 (1933). 



