The Geography of Phytochemical Races

244 5 Wide Disjunctions
J. Agardh f. snackeyi Weber-van Bosse) should be accorded recognition as L. snackeyi
(Weber-van Bosse) stat. nov. Plants collected from sites in Viet Nam yielded the
two halogenated sequiterpenoids palisadin-A [513] and aplysistatin [514]. Plants
collected near Pulau Sipanggau, in Malaysia, however, added a third compound,
5-acetoxypalisadin-B [515], to the array. At the time of writing, at least, those compounds
characterized this species.
Laurencia brongniartii J. Agardh, an alga of tropical and subtropical waters, has
been subjected to chemical analysis by several groups of workers, who studied plants
from the Caribbean Sea (Carter et al., 1978), Japanese waters (J. Tanaka et al., 1988,
1989), and Taiwanese waters (Erickson, 1983). This species elaborates a set of brominated
indole derivatives, some of which also carry sulfur-containing groups. Representative
structures of tribrominated, tetrabrominated, and sulfur-containing compounds
are shown as structures [516, 517, and 518], respectively, in Fig. 5.14. Populations
from the three areas exhibited different profi les based upon these indole derivatives.
Another example of biochemical diversity within this genus came from study
of L. majuscula (Harvey) Lucas from widely separated populations. The major
compounds identifi ed from all populations were derivatives of the spirosesquiterpene
chamigrane system, that is, compounds built on the carbon skeleton seen in compound
[498]. Populations sampled were from Okina-shima, Kochi Prefecture, Japan
(Suzuki and Kurosawa, 1978; Suzuki et al., 1979, 1987); Castelluccio, eastern Sicily
(Caccamese et al., 1986, 1987), Western Australia (Capon et al., 1988), northern
Queensland (Coll and Wright, 1989; A. D. Wright et al., 1990), and the Ryuku
Islands (Masuda et al., 1997b). The major compounds differ among themselves by
variation involving substitution, both position and degree, and oxidation level, that is,
hydroxyl, epoxy, and unsaturations; the fundamental ring structure, and presumably
its biosynthetic origin, is the same throughout.
A fi nal example of extensive chemical variation, this time involving a much
more limited range of sampling, features L. nipponica Yamada. At least nine different
sesquiterpene-based races of this species have been identifi ed from Japanese
waters (Masuda et al., 1997a; Abe et al., 1999).
5.2.17 Codium (Codiaceae)
As part of a study of fatty acids in the Mediterranean taxa, Codium dwarkense
Borgesen and C. taylorii P. Silva), Dembitsky et al. (2003) reviewed the extensive
literature that exists. One of the main observations relative to the present review
was the close similarity of profi les from specimens of C. fragile obtained from
widely separated sites in the Black Sea and in the Pacifi c Ocean near Japan, or from
sites on the coast of France and those from the eastern coast of Russia. Some exceptions
were noted, however, including specimens of C. fragile from Australia. These
observations served to strengthen taxonomic ties considered to exist between entities
collected at these sites and referred to C. fragile. Another observation to emerge
was the grouping of geographically separated species that have been considered
related on the basis of other data.