26 VIOLERYTHRIN 333' 



Solvent: Absorption tnaxima: 



Carbon disulphide 581 541 502 m/j, 



Benzene 554 517 484 m/x 



Petrol 533 498 468 m/x 



Pyridine 560 519 485 m/x 



Ethanol 533 496 464 m/x 



25. ACTINIOERYTHRIN 



This pigment was first obtained by Lederer®^ from sea anemones Actinia 

 equina and was shortly afterwards isolated from the same source by Heilbron 

 and co-workers^. 



For the isolation of the pigment^^- '", the finely cut anemones are extracted with 

 a mixture of ether and acetone (1:1) and the solution is concentrated under reduced 

 pressure. The pigments are transferred to petroleum ether and the solvent is again 

 evaporated. By dilution of the residue with acetone, part of the accompanying 

 phosphatides and steroids can be precipitated. The remainder is frozen out. The 

 pigments remaining in the mother liquors are taken up in petroleum ether and 

 chromatographed on alumina. Actinioerythrin forms a violet-black zone in the 

 upper part of the chromatogram. After elution, the pigment is again adsorbed on 

 calcium carbonate and finally crystallised from absolute ethanol. 30 mg of actin- 

 ioerythrin were obtained from 500 anemones. 



Very little is yet known about the constitution of actinioerythrin. It 

 is not even certain whether it is a carotenoid. According to Lederer^^, 

 actinioerythrin is the ester of a coloured acid. This is supported by the low 

 melting point and by the good solubility in petroleum ether. On alkaline Hy- 

 drolysis, however, Heilbron and co-workers^ obtained a compound, violery- 

 thrin, which showed no acidic properties towards dilute alkalis (cf. below). 

 It was therefore assumed that violerythrin contains one or more enol groups 

 which are isomerised to the stable ketoform. 



Actinioerythrin crystallises from ethanol in brown-violet rhombs, m.p. 85°. 

 It is sparingly soluble in ethanol, but readily soluble in petroleum ether, carbon 

 disulphide, chloroform and pyridine. 



Solvent: Absorption maxima: 



Carbon disulphide 574 533 495 m/x 



Petroleum ether 534 497 470 m/x 



Ethanol 577-518 m/< (broadband) 



26. VIOLERYTHRIN 



Violerythrin was obtained by Heilbron, Jackson and Jones^ by the 

 alkaline hydrolysis of actinioerythrin (of above). The fact that hydrolysis 

 References p. J41—34J. 



