146 



TERPENOIDS AND STEROIDS 



fi 



OCCH. 



0^0 



scilliroside, scillirosidin 

 (Scilla mariti}}ia) 



G-LUCOSE 



Reviews of these compounds have appeared by Tamm (21, 22) and Stoll (23). 



ALKALOIDS 



Nitrogen-containing compounds are included in many of the groups discussed in this 

 chapter. Such compounds possess alkaloidal properties and are normally classed with the 

 alkaloids although their carbon skeletons clearly mark them as isoprenoid derivatives. 

 The most important members of this group are the aconite and steroid alkaloids. The 

 former have been reviewed by Wiesner and Valenta (24), the latter by Prelog and Jeger 

 (25). Several complex diterpenoid alkaloids with structures similar to aconitine and 

 veatchine occur in various species of ^co;»7«;», Z)eZ^/n/?»/«?, Taxus, a.nd Garrya. The 

 steroid and modified steroid alkaloids normally occur as C-3 glycosides or esters. A 

 close resemblance of such structures to the saponins is apparent; in fact solanine has 

 saponin-like properties and is sometimes described as a nitrogen-containing saponin. 

 Some examples of terpenoid and steroid alkaloids are shown below. 



Monoterpenoid: 



actinidine (Actinidia polygama) 



Sesquiterpenoid: 



nupharidine (Nupher kaponicum) 



