The Geography of Phytochemical Races

22 2 Examples Within Continents
Table 2.3 Levels of selected compounds and total monoterpenes, sesquiterpenes, and triketones
from Leptospermum scoparium (from Perry et al., 1997a)
Compound Australian N.Z. North. N.Z. East Cape N.Z. South
α-Pinene 17.3(7.3) a 22.5(3.7) 0.7(0.9) 2.9(3.8)
p-Cymene 4.2(3.6) 0.8(0.8) 0.2(0.0) 0.6(0.7)
1, 8-Cineole 19.9(16.6) 1.6(0.3) 0.3(0.1) 0.7(1.0)
Leptospermone 0.4(0.6) 0.8(0.5) 18.9(0.7) 1.7(1.1)
Isoleptospermone 0.4(0.6) 0.0(0.1) 5.3(0.9) 0.5(0.6)
Flavesone 0.1(0.2) 0.1(0.1) 8.3(0.3) 0.1(0.2)
Total monoterpenes 50.6(24.4) 39.9(4.6) 3.0(1.1) 11.8(9.1)
Total sesquiterpenes 24.7(16.0) 42.1(6.0) 53.7(3.0) 64.7(10.3)
Total triketones 1.2(0.9) 1.0(0.5) 32.5(1.9) 2.4(1.6)
a Percentage of total gas chromatography (GC) peak area (standard deviation).
chemotype characterized by the highest level of sesquiterpenes observed in the
study, along with an array of monoterpenes (Fig. 2.11). Values for the levels of the
defi ning compounds of these chemotypes, along with those of the three classes of
compounds, are summarized in Table 2.3.
Included in the table are data for L. scoparium obtained from fi ve sites in
Australia. The Australian material exhibited a level of α-pinene approaching that
of the northern race from New Zealand, but was clearly characterized by the highest
level of 1,8-cineole observed in the study, along with the highest value for total
monoterpenes and lowest value for total sesquiterpenes. The authors noted the need
for further taxonomic study, particularly of the Australian material.
Häberlein and Tschiersch (1998) have documented geographical variation in the
external leaf fl avonoids of L. scoparium. Plants representing a range of climatic
and geological situations were collected from seven sites from the north and three
from the northern part of the south islands of New Zealand (Fig. 2.11). Detailed
isolation and structural studies afforded an array of O- and C-methylated B-ring
deoxyfl avones and fl avanones, including a very unusual member of the latter class
(see Fig. 2.11 for structures 53–56). Characteristic of these are 5-hydroxy-6,8-di-
C-methyl-7-methoxyfl avone [53], 5,7-dimethoxyfl avanone [54], and the unusual
fl avanone 2,5-dihydroxy-6,8-di-C-methyl-7-methoxyfl avan-3-one [55]. Plants from
the four most northerly sites, Auckland, Coromandel, Rawhiti, and Whangaruru
North, exhibited the highest concentrations of fl avonoids, as well as the full range
of compounds identifi ed, four fl avones and fi ve fl avanones, including the unusual
compound [54]. Plants from the other six locations afforded lower amounts of fl avonoid
material and simpler profi les. The least complex profi les, comprising only two
compounds, 5,7-dimethoxy-6-C-methylfl avanone [56] and 5,7- dimethoxyfl avanone,
were two from the North Island (Te Urewara and Tongariro) and one from the South
Island (Marlborough Administrative Region). The unusual fl avanone was observed
in fi ve of the northern plants and one of the southern ones, which excluded it as a
marker. The possibility that these pigment profi les represent adaptations to local
conditions was not pursued, although the authors clearly indicated that they were
aware that environmental factors might play an important part in this system.
Returning to the terpenes for a moment, it is interesting to note that Perry et al.
(1997b) also examined the essential oils of Kunzea ericoides (A. Rich.) J. Thompson