ABSTRACT
Terpenoid compounds include a multitude of diverse plant constituents which are related by virtue of a common biosynthetic origin. Thus, their basic skeletons are derived from mevalonic acid and consist of C5-units, i.e., the isoprene molecule (CH2=C(CH3)-CH=CH2). They are further classified according to the number of such units present, the simplest C 10-derivatives containing two. These C 10-compounds are known as monoterpenoids and in this book the choice was made to include them in other chapters rather than with their higher relatives. This decision was dictated by their close metabolic relationship to other classes of plant compounds, especially the alcohols, aldehydes, and ketones, and, in contrast, the lack of similarity to the metabolism seen with many of the terpenoids included in this chapter. These latter compounds include the sesquiterpenoids (C I5), diterpenoids (C20), triterpenoids (C30), and tetraterpenoids (C40).
