ABSORPTION AND DIGESTIBILITY OF WAXES 251 



differential saponification method for the separation of waxes from fats. 

 There is little positive in vivo evidence indicating that the waxes contain- 

 ing aliphatic alcohols can be hydrolyzed by enzymes. However, some 

 in vivo experiments demonstrate a partial splitting of such waxes in the 

 gastrointestinal tract. 



a. Jojoba Oil. Savage 22 reported digestibility tests on a liquid wax, 

 commonly referred to as jojoba oil, which is obtained from the nuts of the 

 goat-nut shrub, Simmondsia chinensis (calif or nica) . This lipid contains 

 no glycerol. 23 According to McKinney and Jamieson, 23 the chief acid in 

 jojoba oil is A 1112 -eicosenoic (CH 3 (CH 2 ) 7 CH:CH(CH 2 ) 9 COOH), which 

 accounts for 30.30% of the total. Other acids are A 13 ' 14 -docosenoic 

 (CH 3 (CH 2 ) 7 CH:CH(CH 2 ) u COOH), 14.20%, and saturated acids, 1.64%. 

 The alcohols include A n - 12 -eicosenol (CH 3 (CH 2 ) 7 CH:CH(CH 2 ) 9 CH 2 OH), 

 14.6% and A 13 - 14 -docosenol (CH 3 (CH 2 ) 7 CH:CH(CH 2 ) n CH 2 OH), 33.7%. 24 



The results of digestibility tests on rats with jojoba oil are summarized 

 in Table 1 (page 252). 



The low digestibility of jojoba oil, which approximates 50% when it is 

 fed at the lower dosage and 70% when the material is given at the higher 

 level, is the lowest recorded for limpid fats in rats. Although these ex- 

 periments offer no proof as to whether or not hydrolysis of the wax is a 

 prerequisite to absorption, it was found that the largest proportion of the 

 fecal lipids was composed of unhydrolyzed jojoba oil. However, some 

 free alcohols were present in the feces, although no free fatty acids or soaps 

 could be demonstrated. This would indicate that the higher alcohols 

 may be somewhat more difficultly absorbed from the gastrointestinal 

 tract than are the corresponding acids and soaps; the results also afford 

 evidence that a partial hydrolysis of this wax occurs in the gastrointestinal 

 tract of rats. 



b. Cetyl Palmitate. Munk and Rosenstein 25 reported, many years ago, 

 that cetyl palmitate (CH 3 (CH 2 ) 14 CH 2 OCO(CH 2 ) 14 CH 3 ), when fed as 

 spermaceti, was absorbed by a human subject. These workers, using a 

 patient with a chronic chyle fistula, were able to demonstrate that the 

 palmitic acid moiety appeared in the chyle as tripalmitin, while no trace 

 of the cetyl alcohol could be detected in this fluid or in the feces. The 

 failure to find any cetyl alcohol would suggest that it was destroyed in the 



22 E. S. Savage, A Comparative Study of the Utilization of Jojoba and Cottonseed Oil in 

 the Rat, Thesis, Univ. So. Calif., Dept. Biochem. Nutrit., 1951. 



23 R. S. McKinney and G. S. Jamieson, Oil & Soap, 13, 289-292 (1936). 



M T. G. Green, T. P. Hilditch, and W. J. Stainsby, J. Chem. Soc, 1936, 1750-1755. 

 M I. Munk and A. Rosenstein, Arch. path. Anat. u. Physiol. (Virchow's), 123, 230- 

 279; 484-518(1891). 



