The Geography of Phytochemical Races

106 2 Examples Within Continents
Fig. 2.67 Map showing
range of occurrence of
Satureja douglasii
chemotypes
As is the case with many members of Lamiaceae, Satureja douglasii produces
abundant essential oil from glandular trichomes on the leaves. Gas chromatographic
analysis of the leaf oils from specimens collected throughout the species’ range
revealed the presence of some dozen and a half well-known compounds. The major
compounds identifi ed were camphene [215], camphor [216], which, taken together,
were considered to comprise the “bicyclic” type, carvone [217], pulegone [218],
menthone [219], and isomenthone [220] (see Fig. 2.68 for structures 215–220). The
predominance of each of these major components defi ned a terpene “type.” (All
compounds were observed in each of the terpene types, most in comparatively small
amounts, some only as traces.)
The major structural difference between monocyclic and bicyclic compounds
should be obvious; camphene and camphor exhibit bridged structures. It should be
noted, however, that the monocyclic compounds can be further distinguished from
each other based on the position of the oxygen atom, located at C-2 in carvone,
and at C-3 in pulegone, and in the menthones. Work by others had shown that the