242 



BIOCHEMICAL SYSTEMATICS 



Linear Intei'mediate 



i 

 Cyclic Intermediate 



I I 



Spearmint Types Peppermint Types 



dihydrocarvone 



M. spicata, etc. 



pulegone 



M. pulegium 



menthone 



I 



Acyclic Types 

 C— C=C— C— C— C=C— C=0 



C citral C 



M. citrata 



I diosphenolene 



I M. rotundifolia 



O 



.OH 



M. sylvestris 



diosphenol 



menthofuran 



M. aquatica 



OH 



menthol 



M. piperita, etc. 



Fig. 13-2. Hypothetical biochemical-phylogenetic sequence of 

 peppermint type oils (Reitsema in Jour. Amer. Pharm. Assoc, Sci. 

 Ed. 47: 268. 1958-by permission). 



hydroxyl groups and several keto groups. They may be found as 

 glycosides or agly cones in various parts of the plant, and many species 

 contain an active glucosidase capable of hydrolysing the glycosides to 

 aglycones. The glycosidase is apparently of somewhat low specificity 

 since it is capable of hydrolysing steroidal saponins, the diterpene 



