194 



CAROTENOIDS CONTAINING HYDROXYL GROUPS 



XI 



Ulex europq^us 

 Viola tricolor 



b) In fruit: 

 Arbutus Unedo L. 

 Carica Papaya 

 Citrus aurantium 



Citrus poonensis hort. 

 Cucurbita maxima 

 Diospyros costata 

 Iris Pseiidocorus 

 c) Human liver( ?) 



References 

 C. A. ScHUNCK, Proc. Roy. Soc. 72 (1903) 165. 

 R. KuHN and A. Winterstein, Ber. 64 (1931) 326. — 

 P. Karrer and J. Rutschmann, Helv. chim. Acta 25 

 (1942) 1624; Helv. chim. Acta 2y (1944) 1684. 



K. ScHON, Biochem. J. 2g (1935) 1779. 



R. Yamamoto and S. Tin, Chem. Centr. ig33, I, 3090. 



L. Zechmeister and P. Tuzson, N aturwissenschaften 



ig (1931) 307. — P. G. F. Vermast, Naturwissen- 



schaften ig (1931) 442. 



R. Yamamoto and S. Tin, Chem. Centr. ig34, I, 1660. 



L. Zechmeister and P. Tuzson, Ber. 67 (1934) 824. 



K. Schon, Biochem. J. 2g (1935) 1779. 



P. J. Drumm, F. O'Connor, Biochem. J. jg (1945) 211. 



H. WiLLSTAEDT and T. Lindqvist, Z. physiol. Chem. 



240 (1936) 10. 



Preparation'^ 



Yellow blossoms of Viola tricolor, containing as few deeply pigmented patches 

 as possible, are dried and extracted at room temperature with petroleum ether. 

 The combined extracts are concentrated in vacuum to a small volume and the 

 pigment esters are saponified with a solution of sodium ethoxide in ethanol. The 

 free phytoxanthins are dissolved in methanol, petroleum ether is added, and the 

 violaxanthin is precipitated by very careful addition of water. The crude pigment 

 is filtered and recrystallised from a mixture of methanol and ether. The yield 

 amounts to 0.05 to 0.07% of the dry blossom powder. 



CH3 CHa 



c 



Chemical Constitution^'^ 



CH, 



CH, 



CH, 



CH, 



CH3 CH, 



\/ 

 C 



CH2 C-CH=CH-C=CHCH=CH-C=CHCH=CHCH=C-CH=CHCH=C-CH=CH-C CH^ 



)o o( 



HOCH C C CHOH 



Violaxanthin 



CH» CHo 



HoC CHp 



Since 1931, numerous experiments have been made with the object of 

 elucidating the constitution of violaxanthin. There is some disagreement 

 between the results of different workers and a complete proof of the constitution 

 was only obtained by the partial synthesis of the pigment'^. 



KuHN andWiNTERSTEiN determined the correct molecular formula (C4QHgg04) 

 of violaxanthin'^^. Karrer and Morf^*' subjected the pigment to permanganate 

 degradation and obtained a : a-dimethylsuccinic acid, but no a : a-dimethyl- 

 References p. 214-217. 



