Gastrointestinal toxicity, plants causing

SAFETY PROFILE Poisons by ingestion and inhalation. Powerful irritants. Oxalates are corrosive to tissue and produce local irritation. When ingested they have a caustic effect on the mouth, esophagus, and stomach. The soluble oxalates are readily absorbed from the gastrointestinal tract and can cause severe damage to the kidneys. Oxalates are common components of poisonous plants. When heated to decomposition they emit toxic and irritating fumes. See also OXALIC ACID. 

Plant fertilizers are mildly toxic in small doses, and may lead to gastrointestinal upset and or skin irritation. Larger doses can be more harmful, especially to children, and may cause severe burns, therefore,... 

Biotransformation, especially phase I metabolic reactions, cannot be assumed to be synonymous with detoxification because some drugs (although a minority) and xenobiotics are converted to potentially toxic metabolites (e.g. parathion, fluorine-containing volatile anaesthetics) or chemically reactive intermediates that produce toxicity (e.g. paracetamol in cats). The term lethal synthesis refers to the biochemical process whereby a non-toxic substance is metabolically converted to a toxic form. The poisonous plant Dichapetalum cymosum contains monofluoroacetate which, following gastrointestinal absorption, enters the tricarboxylic acid (Krebs) cycle in which it becomes converted to monofluorocitrate. The latter compound causes toxicity in animals due to irreversible inhibition of the enzyme aconitase. The selective toxicity of flucytosine for susceptible yeasts (Cryptococcus neoformans, Candida spp.) is attributable to its conversion (deamination) to 5-fluorouracil, which is incorporated into messenger RNA. 

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