The Geography of Phytochemical Races

2.7 North and Central America 121
specimens obtained from the Amador County site and only about 10% of those collected
in Mendocino County. Populations at these sites are considered to be relictual and
are thought to have been separated from one another for a considerable period of time.
2.7.25 Echinacea angustifolia (Asteraceae)
Echinacea angustifolia DC., one of the most sought after medicinal herbs in North
America, occurs in a variety of habitats ranging across much of the Great Planes
of the United States north to the Canadian prairies, east to the Appalachian uplands
and to the southeastern coastal plains. The species grows in a variety of habitats
and exhibits a range of morphological forms. A qualitative and quantitative study
of secondary products, with a view to evaluating the phytochemical diversity, was
undertaken by Binns et al. (2002) who sampled nine populations, fi ve in Oklahoma,
two in Kansas, and one each in Nebraska and Iowa, with an overall latitudinal
range of 34.368–42.917 N. Between 8 and 17 individual plants were taken from
each population. Roots of Echinacea are a rich source of caffeic-acid derivatives,
long-chain unsaturated amides, and long-chain unsaturated ketones. Representative
structures of some of the 28 compounds identifi ed in this study are illustrated
below (Fig. 2.77). The family of amides are here represented by structure [246],
Fig. 2.77 Compounds 246–249, caffeic-acid derivatives from Echinacea angustifolia. Compounds
250 and 251, sweet principals from Lippia dulcis