Three poisonous plants (Oenanthe, Cicuta and Anamirta) that antagonise the effect of γ-aminobutyric acid in human brain

Although we are familiar with common British plants that are poisonous, such as Atropa belladonna (deadly nightshade) and Aconitum napellus (monkshood), the two most poisonous plants in the British Flora are Oenanthe crocata (dead man's fingers) and Cicuta virosa (cowbane). In recent years their poisons have been shown to be polyacetylenes (n-C2H2). The plants closely resemble two of the most common plants in the family Apiaceae (Umbelliferae), celery and parsley. Unwittingly, they are ingested by naive foragers and death occurs very rapidly. The third plant Anamirta derives from South-East Asia and contains a powerful convulsant, picrotoxin, which has been used from time immemorial to catch fish, and more recently to poison Birds of Paradise. All three poisons have been shown to block the γ-aminobutyric acid (GABA) system in the human brain that normally has a powerful inhibitory neuronal action. It has also been established that two groups of sedative drugs, barbiturates and benzodiazepines, exert their inhibitory action by stimulating the GABA system. These drugs are the treatments of choice for poisoning by the three vicious plants.

The acute toxicity of water hemlock (Cicuta douglasii) in a goat model

Water hemlock (Cicuta douglasii) is one of the most toxic plants to livestock and humans. Little is known regarding the amount of plant required to cause death. The objective of this study was to determine a lethal dose of water hemlock in a goat model. Plants were dosed to goats via oral gavage of freeze-dried ground plant material. The results from this study suggest that 1-2 fresh tubers would be lethal to goats.