Conocephalum conicum

Table 5.1 Comparison of flavones of Conocephalum conicum specimens from North America and Germany...

Fig. 5.5 Compounds 425 33, essential-oil components from Conocephalum conicum...

Porter, L. J., Mues, R., Zinsmeister, H. D. and Brehm, B. G. 1976. Flavonoid variation in the hverwort Conocephalum conicum evidence for geographic races. Phytochemistry 15 147-150. 

Wood, W. E., Lancaster, W. C., Eisher, C. O. and Stotler, R. E. 1996. frans-Methyl cinnamate the major volatile from some populations of the liverwort Conocephalum conicum. Phytochemistry 42 241-242. 

Adam, K.P., Thiel, R., Zapp, J. and Becker, H. (1998) Involvement of the mevalonic acid pathway and the glyceraldehyde-pymvate pathway in terpenoid biosynthesis of the liverworts Ricciocarpos natans and Conocephalum conicum. Arch. Biochem. Biophys., 354,181-87. 

M. Toyota, T. Saito, and Y. Asakawa, A phenethyl glycoside from Conocephalum conicum, Phytochemistry, 43 (1996) 1087-1088. 

The specific rotation of natural conocephalenol was not given in the original report, therefore we tried to isolate natural product ourselves. However, the liverwort Conocephalum conicum collected in Japan does not contain conocephalenol at all, while the liverwort collected in Europe does contain conocephalenol. We have isolated pure conocephalenol (56) from the German species and the specific rotation is [a]D -4.77°, confirming that the absolute configuration of the natural one should be formulated as depicted in Fig. 6. 

Matsuo, A Nakayama, M Hayashi, S Nagai, K. Fatty acid ethyl esters in the liverwort Conocephalum conicum. Phytochemistry, 1980, 19, 1848-1849. 

Conocephalum conicum (L.) Underw. DQ463118 U87067 N152 Newton 6375... 

Bicycloelemene (227) has been isolated from Conocephalum conicum 313) and detected in both Jungermanniales and the Metzgeriales species 28). The enantiomer of (227) has been isolated from pepermint oil 339) and cold-pressed peel oil of Citrus junos 274, 302, 317). 

Cadinene (247) has been detected in European Conocephalum conicum 87). Reinvestigation of the essential oil American C. conicum resulted in isolation of (—)-8-cadinene (247) whose absolute configuration was established by comparison of its CD spectrum with that of (+)-8-cadinene (5). 

Two new guaianolides, 8a-acetoxyzaluzanin C (426) and 8a-acetoxy-zaluzanin D (427) have been isolated from the female thallus of Conocephalum conicum and sterile thallus of Wiesnerella denudata, together with the previously known zaluzanin C (424) and zaluzanin D (425) (25,40). 

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