The Geography of Phytochemical Races

4.4 South Pacifi c 205
out such a possibility completely. Biosynthetic studies, including comparison of the
enzymes responsible for one or more of the steps, would be helpful. Again, DNA
sequence divergence data would be of critical importance.
4.4.4 Scoparia (Scrophulariaceae)
Mabberley (1997, p. 651) lists Scoparia as a genus consisting of 20 species in
tropical America, and singles out S. dulcis L. as a pantropical weed. T. Hayashi
et al. (1991, 1993) reported that plants collected in Taiwan, China, and Thailand
were characterized by a set of compounds that had not been reported from plants
collected in Paraguay, and therefore represented a new chemotype in the species.
Examination of a collection of S. dulcis from Indonesia revealed the Paraguayan
array of compounds. All of the compounds identifi ed in these studies were shown to
be diterpene derivatives, acids in the case of the material from Paraguay as shown
in structures, such as scoparic acid [360], scopadulcic acid [361], and scopadulcin
[362]. The newly identifi ed compounds, scopadiol [363] and scopadulciol [364] (see
Fig. 4.13 for structures 360–364), share the same basic carbon skeleton with the
compounds isolated from the Paraguayan material, but differ in the level of oxidation
of C-18, exhibiting either the primary alcohol function (−CH 2 OH) or the carboxyl
group (−COOH).
4.4.5 Fuchsia (Onagraceae)
The genus Fuchsia consists of perhaps 100 species, enjoys a wide distribution,
and offers a variety of systematic and evolutionary challenges. In addition to
attracting purely botanical interest, Fuchsia is also of considerable horticultural
value. Our interest in the genus concerns sect. Skinnera which consists of three
New Zealand species, F. excorticata L. f., F. perscandens Cockayne & Allan,
and F. procumbens R. Cunn., and the Tahitian endemic F. cyrtandroides Moore.
A fourth taxon, F. x colensoi Hook. f. occurs wherever the ranges of F. excorticata
and F. perscandens overlap.
Two groups of workers have investigated the fl avonoids of this group of species,
Averett et al. (1986) and Williams and Garnock-Jones (1986). Both groups
reported kaempferol and quercetin 3-O-mono- and 3-O-diglycosides and a set of
fl avone derivatives. Although there is overall agreement in the classes of compounds
reported in these two papers, there are some differences: the number of
fl avonol glycosides present in each species, the number of fl avones represented, and
the nature of the fl avone sulfate derivatives. It is the pattern of occurrence of the
fl avonoid classes, fl avonol versus fl avone, and the presence or absence of sulfated
fl avone derivatives, rather than the individual compounds, that provide important
clues to relationships among the species.