532 



IX. CAROTENOIDS AND VITAMINS A 



Table 3 

 Carotenoid Derivatives Having Provitamin A Activity 



Derivative 



Empirical 

 formula 



Reference 



AU-trans-P- 



carotene =100 



/3-Carotene set 



5,6-Dihydro-/3-carotene 



/8-Carotene monoepoxide 



/3-Carotene monofuranoxide (Mutatochrome) 



Vitamin A-epoxide (Hepaxanthin, "574-chromo- 



gen") 

 /3-Carotene diepoxide 

 /3-Carotene difuranoxide (Aurochrome) 

 /3-Carotene monoepoxide monofuranoxide 

 Rubixanthin epoxide monofuranoxide (Rubi- 



chrome ) 

 /3-Carotene monoxide 

 5,!6-Dihydroxy-/3-carotene 

 Semi-|8-carotenone 

 /3-Oxycarotene 

 Anhydrosemi-|8-carotenone 

 i8-Carotenal 

 /3-Apo-2-carotenal 

 /3-Apo-2-carotenol 

 iS-Apo-4-oarotenaI 

 j3-Apo-4-carotenol 

 /3-Carotene diiodide 

 16,16'-Homo-/3-carotene 

 a-Carotene set 



All-^rans-a-carotene 

 5,6-Dihydro-a-carotene 

 a-Carotene monoepoxide 

 a-Carotene diiodide 

 7-Carotene set 

 A\\-trans- 7-carotene 

 In rat 



ex Mimulus longiflorus (monkey-flower) 

 ex Pyracantha angustifolia Sohneid. (narrow- 

 leaf firethorn) 

 ex pro-7-rarotene by iodine catalysis 

 In chicks 



ex pro- 7-carotene by stereoisomerization 

 Cryptoxanthin set 



AU-irans-cryptoxanthin 

 In rats 



In chicks 



Isocryptoxanthin 



Isocryptoxanthin methyl ether 



C4oH56^^ 



ar, 42% 



ad, 54-59%; ae, 



50%; af, 



57%; ag, 



60% 

 ah, 55% 

 at, 48%, 

 ai, 52% 



