CAROTENOLS AND OXYCAROTENOLS OF THE C40 SERIES 503 



have prepared chromatographically pure zeaxanthin from the above 

 source. This carotenol Hkewise occurs along with lutein in the feathers of 

 Serimis canorius (wild canar}^-^'^ 



b. Related Compounds, (a) Physalien, C72H116O4. Physalien was first 

 reported^^" in the winter cherry {Physalis alkekengi) and also in the 

 Chinese lantern plant (Physalis francheti). It was shoA\Tn to be a dipalmi- 

 tate of zeaxanthin. 



The proof of the ester structure of physalien is based upon several facts. 

 In the first place the molecular weight is about double that of carotene, and 

 approaches 1000. Second, the melting point is about 100° higher than 

 that of the leaf carotenoids. Finally, physalien does not follow the 

 classical rule of solvent distribution between petroleum ether and dilute 

 methanol for the oxygen-containing carotenoids, but rather follows the 

 pattern of the polyene hydrocarbons, carotene and lycopene. On saponifi- 

 cation, physalien gives rise to two molecules of palmitic acid and one of 

 zeaxanthin "*~^^^ as follows: 



CisH3iCO-OC4oHmO-CO-C,5H3i + 2K0H > HOC40H54OH + 2Ci5H3iCOOK 



Physalien Zeaxanthin Potassium 



palmitate 



Studies on the chemical nature of the carotenoid portion of physalien have 

 shown it to be identical with zeaxanthin. Like zeaxanthin, it absorbs 11 

 molecules of hydrogen to give perhydrophysalien or perhydrozeaxanthin 

 dipalmitic acid ester. All color is lost after 8 molecules of hydrogen have 

 been absorbed. 



Besides being present in the berries and calices of the Physalis alkakengi 

 and P. francheti, and Lycium halimifolium (box thorn, matrimony vine),^^^ 

 physalien has been reported by Winterstein and Ehrenberg^'* as present in 

 the berries oi Lycium barbarum (Barbaiy wolf berry), of Solanum hendersoni 

 (Jerusalem cherry), and of Asparagus officinalis (asparagus berries). It 

 has also been found as a component of the berry pigments of Hippophae 

 rhamnoides (sea buckthorn). ^^^ 



Phj'salien can be partially synthesized from zeaxanthin and palmitic 

 acid."^ It can be prepared from the calices of the Physalis, in which the 

 pigment usually comprises 0.9 to 1.8% of the dry weight. It ciystallizes 

 from a bcnzcne-methanol mixture in long flat rods cut off obliquely at the 

 ends, or in fine, inidulating needles. When crystallized from a cyclohexane- 

 ethanol solution, it forms long, flat, deep-red prisms. The ester melts at 

 98.5-99.5°C. It has an excellent solubility in carbon disulfide, benzene, 

 chlorofonn, and carbon tetrachloride; it dissolves fairly well in ether, 

 petroleum ether, hexane, and pyridine. It is soluble to a small extent in 



»«» R. Kuhu and \\'. v. Wit-gand, Hdr. Chim. Acta, 12, 490-oOG (1929). 

 "1 P. Karrer and H. Wehrli, Helv. Chim. Acta, 13, 1104-1105 (1930). 



