The Geography of Phytochemical Races

6.2 The Hawaiian Islands 253
6.2.2 Cyperus rotundus (Cyperaceae)
Cyperus rotundus L. is a weedy species, native to India, but widely distributed in
countries on the Pacifi c Rim and islands in the Pacifi c Basin. Commonly referred to
as “purple nut sedge,” it has been known in the Hawaiian Islands since the middle of
the nineteenth century. In addition to its weedy nature, the taxon has attracted attention
because of the antifebrile activity of its rhizomes. Chemical studies have disclosed
the presence of several sesquiterpene derivatives, some of which have been
implicated in the plant’s medicinal use (cyperene and cyperinerol) (Wagner et al.,
1990, p. 1399). Our interest in this species is the existence of several chemotypes
with interesting patterns of occurrence involving Pacifi c Rim countries and several
oceanic islands, including the Hawaiian Islands, islands in the southern Pacifi c, and
the Philippines.
Sesquiterpenes identifi ed from the sedge include cyperene [536], cyperotundone
[537], patchoulenone [538], patchoulenyl acetate [539], sugeonyl acetate [540], and
ß-selinene [541] (see Fig. 6.4 for structures 536–541). Several chemotypes involving
these compounds have been identifi ed, although there is overlap in the countries
involved in some instances (Komai et al., 1991). The “H-type” occurs in Japan and
in the Kalapana area of southeastern Hawaii (Island of Hawaii). Plants exhibiting the
“M-type” chemical phenotype occur in Japan, Taiwan, southern China, Hong Kong,
and Vietnam. “O-Type” plants occur in Japan; Taiwan; the Philippines; Thailand;
Indonesia; the Hawaiian Islands (Hawaii, Kauai, Maui, and Oahu); southern Pacifi c
Islands, including Guam, Samoa, Saipan, Palau, and Tonga; Australia; and southern
United States. The “K-type” plants are known from four of the Hawaiian Islands
(Hawaii, Kauai, Maui, and Oahu), southern California, and Mexico. Despite the
presence of both H- and O-chemotypes, the predominant chemotype in the Hawaiian
Islands is the K-type. Selected occurrence data are summarized in Table 6.1.
Fig. 6.4 Compounds 536–541, sesquiterpene derivatives from Cyperus, the nut sedge