TERPENOIDS AND STEROIDS 



Gossypol of cotton is: 



127 



HO OH 



CHO 



CHj CHj 



SESQUITER PENOIDS 



The sesquiterpenoids are C15 compounds, usually regarded as derived from three 

 isoprene residues. Like monoterpenoids they are found as constituents of steam-distillable 

 essential oils. The general utility and occasional exceptions to the isoprene rule which 

 were mentioned earlier apply also in this group of compounds. 



The most important member of the acyclic sesquiterpenoids is the widely-distributed 

 alcohol farnesol: 



Its pyrophosphate is a key intermediate in terpenoid biosynthesis. Certain furanoid ter- 

 penoids are also classed as aliphatic since they are not carbocyclic. Examples of this 

 type are ngaione and myoprone from the essential oils of Myoporum spp. 



ngaione 



myoporone 



