The Geography of Phytochemical Races

2.4 The Mediterranean Basin 59
(Zaidi et al., 1998). Quite signifi cant differences inn numbers of compounds and
relative degree of complexity were noted by those authors: only two compounds
were found in Spanish plants, whereas plants from the Algerian mountains afforded
a richer array of 6- and 8- substituted fl avones, along with an assortment of simpler
derivatives of apigenin and luteolin. The authors suggested that the differences
could be accounted for by “geographical and climatic differences combined with
effi cient genetic isolation.” A “high altitude” topodeme, M. suaveolens subsp. timija
(Cosson ex Briq.) Harley from Morocco has been recognized. The authors were not
unaware of the possibility that the chemical differences simply refl ected the existence
of “true chemotypes” with no correlated morphological features.
2.4.8 Teucrium polium (Lamiaceae)
Going slightly farther afi eld in this next example, we look at some of the differences
that Kamal and Sandra (1994) noted in their examination of two varieties of
Teucrium polium L. var. album (Mill.) Fiori occurs along the Mediterranean coast
of Egypt and in Sinai, whereas var. pilosum Decne [= T. pilosum (Decne) Asch. &
Schweinf] is native to Qatar. Earlier papers had described iridoids, fl avonoids (Rizk
et al., 1986), and volatile components (Wassel and Ahmed, 1974; Hassan et al.,
1979; Vokou and Bessiere, 1985) of T. polium from several geographic regions, that
is, Egypt, Qatar, Saudi Arabia, and Greece. Kamal and Sandra (1994) examined the
volatile components of both varieties using GC-MS analysis, which allowed them to
identify 70 of the 93 compounds (peaks) observed. Signifi cant quantitative as well
as qualitative differences were observed a sample of which are shown in Table 2.11.
These data add signifi cantly to the list of differences between the two varieties; they
might be used as well in support of recognition of separate species status for the
two, as has been suggested in the past.
Table 2.11 Variation within Teucrium polinum (after Kamel and Sandra, 1994)
Compound Varieties
album pilosum
α-Pinene 4.05a ndb β-Pinene 4.90 0.28
Myrcene 1.59 nd
4-Terpinyl acetate 1.03 nd
Humulene 0.28 2.28
Germacrene-D 1.44 4.42
γ-Cadinene 2.60 18.04
δ-Cadinene 4.05 8.30
Spathulenol nd 11.59
β-Eudesmol 3.31 19.14
Patchouly alcohol 33.34 2.77
a Percentage of component in oil.
b nd = Not detected.