59 - 



Properties of the Xanthophylls from the Green Algae 



The minor xanthophyll observed between the neoxanthin and the 

 violaxanthin from many of the green algae in Appendix IV was isolated 

 by adsorption in columns of powdered sugar. The eluted pigment was 

 purified by adsorption in columns of magnesia followed by readsorption 

 in columns of sugar. Its spectral absorption curves in petroleum 

 ether and in ethanol, shown in Figure II, Uj are similar to the oiirves 

 for lutein-^*^*^. Dissolved in diethyl ether and treated with concen- 

 trated hydrochloric acid, this xanthophyll did not yield a blue color, 



Siphonaxanthin and siphonein were isolated from various species 

 of the siphonalean green algae. As shown by adsorption of mixtures 

 of these preparations, the same pigments were obtained from all the 

 specieso The siphonein was converted into siphonaxanthin by saponi- 

 fication with alcoholic potassium hydroxide. Spectral absorption 

 curves of the two pigments are shown in Figure II, 5» 



Although siphonaxanthin resembles fucoxanthin of the diatoms and 

 brown algae with respect to spectral absorption curves, as shown by 

 Figure 11,6, the two pigments differ greatly in other ways. With hy- 

 drochloric acid and ether, fucoxanthin yields a deep blue color in 

 the acid, siphonaxanthin does not, Fucoxanthin is decomposed by 

 alkalies, siphonaxanthin is not. In columns of powdered sugar 

 siphonaxanthin is sorbed above neoxanthin, whereas fucoxanthin is sorbed 

 far below neoxanthin and between violaxanthin and tareoxanthin^* , 

 In columns of magnesia and with petroleum ether plus 25 per cent ace- 

 tone, siphonaxanthin is also strongly adsorbed above neoxanthin and 

 zeaxanthin, 



Siphonein resembles fucoxanthin in sorbability as well as with 

 respect to spectral absorption. It is sorbed with fucoxanthin in 



