The Geography of Phytochemical Races

5.2 Nonvascular Plants 225
of the Atlantic were the presence of (+)-cis-2-hydroxycalamenene [412] from the
former, and (−)-δ-cuparenol [413] from the latter (see Fig. 5.4 for structures). This
difference is interesting, in that it is akin to the observations of Konecny et al. (1985)
that this liverwort collected in Czechoslovakia afforded compound [412], whereas
material obtained from Japan yielded compound [413].
5.2.6 Conocephalum conicum (Conocephalaceae)
The fi rst indication that Conocephalum conicum (L.) Dum., a thallous liverwort widely
distributed in the Northern Hemisphere, consisted of geographically separated chemical
races came from study of two widely separated collections by Markham et al. (1976).
Plant material from Germany (Saarland) and the United States (Washington State) exhibited
not only several fl avonoid derivatives in common but also compounds unique to
each site. The arrays of compounds held in common were identifi ed as O-glycosides
of apigenin [414], luteolin [415], and luteolin 3′-methyl ether (chrysoeriol) [416],
and the fl avone di-C-glycosides apigenin 6,8-di-C-glucooside (vicenin-2) [417] and
luteolin 6,8-di-C-glucoside (lucenin-2) [418] (see Fig. 5.4 for structures). The O-linked
sugar was glucuronic acid in all cases, with additional rhamnose residues in some. The
distribution of these compounds in shown in Table 5.1.
Subsequently, Porter (1981) expanded the survey by looking at specimens collected
over a much larger part of the range of the species: 23 sites in Europe, fi ve
in North America, and six in Asia. The majority of compounds identifi ed were
again revealed as derivatives of apigenin, luteolin, and chrysoeriol, with the major
Flavonea Table 5.1 Comparison of fl avones of Conocephalum conicum specimens from North America and
Germany
North America Germany
Vicenin-2 + +
Lucenin-2 + +
Apigenin 7-Gln + +
Luteolin 7-Gln + +
Chrysoeriol 7-Gln + +
Apigenin 7-Gln-4′-Rhm + +
Luteolin 7-Gln-4′-Rhm + +
Chrysoeriol 7-Gln-4′-Rhm + +
Apigenin 7,4′-diGln − +
Luteolin 7,4′-diGln − +
Apigenin 7-diGln-4′-Rhm − +
Luteolin 7,3′-diGln + −
Luteolin 7-Gln-3′,4′-diRhm + −
Two Luteolin 7-Gln derivatives + −
a Vicinin-2 and lucenin-2 = apigenin and luteolin 6,8-di C-glucosides;
Gln = glucuronic acid; Rhm = rhamnose.