Helenium microcephalum

Helenium microcephalum is a herbal plant distributed in the South of the USA, and in North Mexico, where it is responsible for poisoning of cattle, sheep and goats. The toxic substance is helenalin (29, 30). 2.5 g of fresh plant material per kg body weight lead to the death of the animals. The symptoms occur early, after one hour already and include salivation, colic, diarrhea, vomiting and progressive faintness, and finally death, usually within 24 hours. Post mortem findings include changes in liver, heart, brain, kidney, and mucosa (31). 

Sesquiterpene lactones from Parthenium species were strongly inhibitory to growth of larvae of Helicoverpa zea and Spodoptera exigua (Isman and Rodriguez, 1983). Tenu-lin (111), the major sesquiterpene lactone of Helenium amarum, imparts a bitter taste to milk and is toxic to livestock. Helenalin (112) from Helenium microcephalum is toxic to several mammalian species in oral doses as low as 85 fjLg/kg. Hymenoxys odorata, from which a toxin, hymenovin... 

Fig. 98.3 Compound 13 apressin has been isolated from Achillea depressa [19], 14 3-chlorodehydroleucodm liom Kaunia lasiophihalma [20], 15 saussureamine from Saussurea lappa [21], 16 crepidiaside B from Cichorium intybus and other species [22], 17 lappaphen A from Arctium lappa [23], 18 from Apalochlamys spectabilis [24], 19 from deep sea gOTgraiian (Placogoria sp.) [25] but also from terrestrial plants Taraxacum wallichii [26] and Artemisia gilvescens [27], and the norguaianolide (20) mexicanin E from Helenium microcephalum [28]...

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