Pyrrolizidine alkaloids, flavonoids and volatile compounds in the genus Eupatorium. Eupatorium cannabinum L., an ancient drug with new perspectives.

Abstract

Within the scope of a study of antitumour compounds in higher plants a survey is given concerning the presence of pyrrolizidine alkaloids, flavonoids and volatile compounds in Eupatorium species. Preliminary results of a phytochemical study of these compounds in E. cannabinum are also presented. From the results of a GC-MS analysis of an alkaloid extract from aerial parts of E. cannabinum the conclusion can be drawn, that the composition of pyrrolizidine alkaloids is more complicated than reported in literature. This is caused by the fact that different stereoisomers exist. The presence of at least two alkaloids with a molecular weight of 283 (supinine or isomers) and four alkaloids with a molecular weight of 299 (echinatine or isomers) could be shown. In subterranean plant material also other pyrrolizidine alkaloids are present. A great number of flavonoids, also as glycosides, have been shown in Eupatorium species, often in low quantities. Rutin, present in many Eupatorium species, could not be detected in subterranean parts of E. cannabinum. Relatively little attention has been paid to the analysis of volatile compounds (essential oils) of Eupatorium species. Thymol derivatives are often reported to be present in Eupatorium species. Thirty-five compounds could be detected by means of a GC-MS analysis in the essential oil of E. cannabinum about which no literature data were available.