2o8 CAROTENOIDS CONTAINING HYDROXYL GROUPS XI 



Occurrence 



Flavoxanthin occurs fairly widely in plants, but only in small concentrations 

 and not as the main pigment. 



TABLE 45 



OCCURRENCE OF FLAVOXANTHIN 



Source References 



Dandelion P. Karrer and J. Rutschmann, Helv. chim. Acta 23 



(1942) 1144. 

 Ranunculus acer R. Kuhn and H. Brockmann, Z. physiol. Chem. 213 



(1932) 192. — P. Karrer, E. Jucker, J. Rutschmann 



and K. Steinlin, Helv. chim. Acta 28 (1945) 1146. . 

 Sarothamnus scoparius P. Karrer and E. Jucker, Helv. chim. Acta 2y (1944) 



1585. 

 Senecio vernalis ( .'') R. Kuhn and H. Brockmann, Z. physiol. Chem. 213 



(1932) 192. 

 Ulex europaeiis K. Schon, Biochem. J . 30 (1936) 1960. 



Viola tricolor P. Karrer and J. Rutschmann, Helv. chim. Acta 27 



(1944) 1684. 



Preparation 



According to Kuhn and Brockmann^^*, the pigment is best extracted from 

 crowfoot blossoms. The yield amounts to approximately 40 mg flavoxanthin 

 from I kg of blossoms. Karrer and Rutschmann^^* extracted phytoxanthin 

 from dandelion blossoms by means of petroleum ether and obtained 80 mg of 

 pure flavoxanthin from 1.5 kg of dry blossoms. 



a) Flavoxanthin from Ranunculus acer: The dried and finely ground blossoms 

 are extracted with methanol at room temperature and the solution is concentrated 

 to a small volume in vacuum. The pigments are then extracted with ether and sapo- 

 nified with alcoholic potassium hydroxide. After partitioning into an epiphasic and 

 hypophasic fraction the phytoxanthins are chromatographed on calcium carbonate 

 from a mixture of benzene and petrol, and the chromatogram is developed with 

 petrol. The flavoxanthin is eluted with petrol containing 1% of methanol and 

 crystallised repeatedly from methanol. 



b) Flavoxanthin from dandelion: The dried and finely ground dandeUon 

 blossoms are continuously extracted with petroleum ether and the pigments are 

 saponified with methanolic hydroxide. After a separation into hypophasic and 

 epiphasic constituents, the former are subjected to a preliminary purification by 

 adsorption on alumina. The crystalline mixture of phytoxanthins is adsorbed on 

 zinc carbonate, and eluted with ether containing methanol. Pure flavoxanthin is 

 obtained by crystallisation from methanol. 



References p. 214-217. 



