Dichapetalum cymosum Fluoroacetic acid

Fluoroacetic acid is the toxic principle of the South African plant gifblaar, Dichapetalum cymosum = Chailletia cymosa) (Dichapetalaceae). Crystals. M.p. 33° to 35°. B.p. 165° to 168°. Soluble in water and ethanol practically insoluble in most common organic solvents. 

Fluoroacetic acid has been identifled as the toxic component of the South African plant gijblaar (Dichapetalum cymosum) [34]. Its mechanism of action is based on inhibition of the citric acid cycle, the main source of metabolic energy in all animals [35]. In this cyde, fluoroacetate can replace acetate as a substrate of aconi-tase, an enzyme complex which usually forms dtrate by addition of acetate to a-oxoglutarate. The resulting fluorocitrate is binds tightly to the enzyme, but cannot be further converted to ds-aconitate and isocitrate [36], thus inhibiting aconitase. 

Huoroacetic add CHjF-COOH, a very poisonous carboxylic acid which is converted in the tricarboxylic acid cycle to fluorocitrate, a strong inhibitor of aconitase. The Thcarboxylic add cycle (see) therefore ceases to operate, with lethal results. Free F.a. occurs in the leaves of Dichapetalum cymosum, a poisonous African plant which is reponsible for cattle poisoning in South Africa. It is aira present in other plants to which it confers toxidty. [L.P. Miller and EFIemion Phytochemistry 3 (1973) 1- j nuorodtric add see Fluoroacetic add. 

Fluoroacetic acid was identified as the toxic principle of Dichapetalum cymosum, which is one of the most poisonous plants growing in South Africa (70). This acid was subsequently found in many plants belonging to several families in Africa and Australia. The seeds of D, toxicarium contain, besides a small amount of fluoroacetic acid, cofluorooleic acid as the major toxic compound (91). The presence of cu-fluoropalmitic, o>fluorocapric, and cu-fluoromyristic acids have also been reported (122). Biosynthesis of fluoroacetic acid has been proposed to occur by a nucleophilic incorporation of a fluoride ion into a C3 unit linked to... 

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