CIS-ISOMERE XANTHOPHYLLE IN PFLANZEN

A method for separation of cis-trans isomeric xanthophylls on thin layers of Mg2(OH)2CO3 has been developed. This method proved useful for separating mixtures of isomers obtained by iodine catalysis of lutein, taraxanthin (=luteinepoxide), violaxanthin, antheraxanthin and zeaxanthin. With this new method we have found, in a large number of plant extracts, two now well-defined cis-isomers besides the all-trans configuration. They are named neo U and neo V according to Zechmeister's nomenclature. Their properties and distribution are described and the positions of the cis-bonds discussed. © 1970.