272 



CAROTENOID CARBOXYLIC ACIDS 

 2. CROCETIN C20H24O4 



XIII 



History 



1818 AscHOFF^^ investigates the pigment of saffron and terms it crocin. 

 1852-1914 Different workers®* carry out investigations on crocin. The glyco- 



sidic nature of crocin is recognised. 

 1915 Decker®^ isolates the still inhomogeneous aglycon (crocetin) from crocin. 

 1927-33 Karrer and Salomon^® and Karrer and co-workers®^ elucidate the 



constitution of crocin and crocetin®^. 



Occurrence 



Crocin is the colouring principle of saffron which has been employed in 

 different countries since early times. Crocin was shown by Karrer and Miki® 

 to be the digentiobiose ester of crocetin. Besides crocin, Crocus sativus contains 

 small quantities of crocetin* and also of ^-carotene, y-carotene, lycopene and 

 zeaxanthin. A colourless glycoside, picrocrocin (saffron bitter) which is closely 

 related to crocin, has also been isolated^"". 



TABLE 51 



Source 

 a) In blossoms: 

 Crocus sativus L. 



Crocus albiflorus Kit., var. 



Neapolitanus hart. 



b) In fruit : 



Gardenia grandiflora Lour. 



c) In blossom leaves: 

 Cedrela Toona Roxb. 



Crocus luteus 

 Nyctanthes Arbor-tristis 

 V erbascum phlomoidcs L. 



OCCURRENCE OF CROCETIN 



References 



B.Wmss, J . prakt. Chem. (1) 1 01 (1867) 65; Jb. Fortschr. 

 d.Chem.j86y, 733. — of. B.Qu avr at, J . prakt. Chem. ^6 

 (1852) 68; Jb. Fortschr. d. Chem. 18 51, 532. 

 R. KuHN, A. WiNTERSTEiN and W. WiEGAND, Helv. 

 chim. Acta 11 (1928) 718. 



F. RocHLEDER and L. Mayer, /. prakt. Chem. (1) 72 

 (1857) 394; 7^ (1858) l; Jb. Fortschr. d. Chem. 1857, 

 490; 1858, 475. — R. Kuhn and co-workers, Helv. chim. 

 Acta II (1928) 718. 



E. G. Hill and A. P. Sikkak, /. Chem. Sac. gi (1907) 



1501. — A. G. Perkin, /. Chem. Soc. loi (1912) 1540. 



— R. Kuhn and A. Winterstein, Helv. chim. Acta 12 



(1929) 496. 



R. Kuhn, A. Winterstein and W. Wiegand, Helv. 



chim. Acta 11 (1928) 718. 



E. G. Hill and A. P. Sikkar, /. Chem. Soc. gi (1907) 



1501. 



L. ScHMiD and E. Kotter, Monatsh. 5g (1932) 340, 



353. 



Concerning the stereochemistry of natural crocetin from Crocus sativus, see R. Kuhn 

 and A. Winterstein, Ber. 66 (1933) 209; 67 (1934) 34^- 

 References p. 2^0-294. 



