The Geography of Phytochemical Races

226 5 Wide Disjunctions
differences being additional combinations of glucuronic acid and rhamnose in the
O-linked glycosides, and the addition of C-glycosylfl avones involving arabinose
and rhamnose. All C-glycosylfl avones identifi ed in the expanded study had sugar
substitutions at both positions C-6 and C-8. Newly described in that study was the
aurone aureusidin 6-O-glucuronide [419], which was seen a single specimen from
France. Although the aurone does not play any role in the immediate story, it is interesting
to note that it has also been identifi ed in a specimen of C. supradecompositum
from Japan.
Vicenin-2, apigenin, and chrysoeriol 7-O-glucorinides, and apigenin 7,4-di-Oglucuronide
were essentially ubiquitous, and thus of no use in defi ning races. Presence
and absence data involving other compounds, however, suggested distinct regional
specializations outlined as follows: (1) Other than vicenin-2, C-glycosylfl avone
profi les are clearly specialized; lucenin-2 occurs only in North American plants, the
violanthin-isoviolanthin pair (apigenin-6-C-glucoside-8-C-rhamno side and the isomer
with the sugars reversed) occurs only in Japanese and North American plants,
shaftoside (apigenin-6-C-glucoside-8-C-arabinoside) occurs only in Asian plants,
and chrysoeriol 6,8-di-C-glucoside occurs only in European and North American
plants. (2) Luteolin is absent from all but a very few European samples, whereas it is
well represented in the other areas. (3) Apigenin 7-O-diglucuronide and chrysoeriol
7,4′-di-O-glucuronide were not observed in Japanese plants. (4) Two samples from
Bulgaria were characterized by a compound thought to be a derivative of acacetin
(apigenin 4′-methyl ether). Porter viewed the comparative richness of the North
American profi les as a possible indicator of origin, or “original watershed of the
species.”
In addition to the greater regional differences, some additional fi ne structure
emerged from Porter’s wider survey. There was indication that plants with simpler
fl avonoid profi les were often less robust than those with a fuller complement
of pigments. Populations from both Great Britain and Germany showed this sort
of correlation. Biochemical differences (electrophoretic data) correlated with morphological
differences in populations of this taxon in Poland (Szweykowski and
Bobowicz, 1979). Two fl avonoid races appear to exist in Japan, with material from
the island of Shikoku exhibiting a comparatively simple profi le, whereas material
from Honshu and Kyushu, which have very similar profi les, is characterized by a
richer array of compounds that includes a unique acylated derivative of apigenin
7,4′-di-O-glucuronide.
One of the distinguishing features of liverworts is their capacity to produce a
variety of volatile, often very fragrant, oils that occur in oil bodies distributed over
much of the surface of the organism. Several of these volatile compounds fi gure prominently
in defi ning geographically different chemotypes in several countries. Toyota
et al. (1997) examined 280 specimens of C. conicum collected at Kamikatsu-cho
and Katsuura-cho, both Katsuura-gun, Tokushima. Three chemotypes were identifi
ed based upon their major components. Chemotype-I-accumulated (−)-sabinene
[420], chemotype-II-accumulated (+)-bornyl acetate [421], and chemotype III
was characterized by methyl cinnamate [422] (see Fig. 5.4 for structures). In addition
to a number of compounds known from previous studies of C. conicum, three