PHYTOSTEROL 17 



Colour Reactions. — (i) Crystals of cholesterol pressed on 

 a white porcelain surface and moistened with a drop of sul- 

 phuric acid (5 parts concentrated acid to i part of water) turn 

 pink. The addition of a drop of dilute iodine causes a play 

 of colours from red to blue or green. 



(2) A solution of cholesterol in chloroform gently agitated 

 with concentrated sulphuric acid turns red, while the sulphuric 

 acid which forms the lower layer assumes a green fluorescence. 



(3) On the addition of concentrated sulphuric acid drop 

 by drop to a little cholesterol dissolved in a mixture of 2-3 

 drops of chloroform and about 10 drops of acetic anhydride, a 

 transient pink colour is at first formed ; on the addition of 

 more acid, however, the colour changes to blue and finally to 

 green. 



Phytosterol or Sitosterol. 



The term phytosterol was at one time employed to 

 designate a definite chemical individual of the formula 

 C27H45OH, but it is now used more as a generic term to include 

 a number of different substances having certain properties 

 in common. Thus Windaus and Hauth * showed that the 

 substance obtained from Calabar beans and commonly known 

 as phytosterol was in reality a mixture of two substances — 

 {a) Sitosterol of the formula C27H45OH, and {b) Stigmasterol 

 C3(,H4^0H, an observation which has been confirmed by 

 Sal way. f 



Similarly Klobb \ describes a dextro-rotatory phytosterol of 

 the formula Q^-^^^, SHgO occurring in Anthemis nobilis and 

 a number of laevo-rotatory phytosterols of different formulae 

 obtained from Matricaria Chamoniilla, Tilia europaea, Linaria 

 vulgaris^ and Verbascuni Thapsus.\ 



All vegetable fats contain phytosterol, the amount varying 

 from about 0'i3 to 0*30 per cent and rising in the case of pea 



* Windaus and Hauth: " Ber. deut. chem. Gesells.," 1906, 39, 4378; 1907, 

 40, 3681. 



t Salway: " Journ. Chem. Soc, Lond.," 1911, 99, 2154. 



J Klobb: " Compt. rend.," 1911, 152, 327; "Ann. Chim. Phys.," 1911, viii,, 

 24, 410. 



§See also Power and Rogerson : "Journ, Chem. Soc, Lond.," 1910,97, 1951; 

 Rogerson: " Amer. Journ. Pharm.," 1911, 83, 49; "Journ. Chem. Soc, Lond.," 

 1912, loi, 1040. 



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