1 Natural Poisons

1.1 Definitions

• Poisons are substances that, under certain circumstances, can cause temporary or permanent harm to the body, organs, tissues, cells, or DNA, or can lead to death when introduced or absorbed.

• Toxins, also called 'natural poisons', 'biological poisons', or 'biotoxins', are poisons produced by living organisms. The term 'toxin' was first used in 1890 by the physician Ludwig Brieger (1849-1919), professor at the Humboldt University in Berlin, during his work with bacterial poisons. Initially, the term was used to describe animal or bacterial compounds that trigger the formation of antibodies in animals and humans.

• Today, the term 'toxin' is used with different meanings:

  • as a general expression for poisons produced by living organisms, or

  • as an expression for natural or synthetic poisons that target specific organs, e.g., nephrotoxins (damaging the kidneys), hepatotoxins (harming the liver), cardiotoxins (harming the heart), or hemotoxins (damaging red blood cells), regardless of whether they are of natural or synthetic origin.

• Toxicant is a poorly defined term. Mostly, it is used to describe a toxic substance capable of causing deleterious effects in living organisms. Some authors include in this category only man-made synthetic substances showing such effects.

• Toxicology is the scientific discipline describing poisons, poisonings, kind of action of poisons and potential treatments of poisoned organisms.

• Toxinology is a branch of toxicology. It comprises the knowledge about the chemistry of natural poisons, the biology of their producers, their biosynthesis, their pharmacokinetic behavior (toxicokinetics), their mechanism of action (toxicodynamics), their effect pattern on the affected living being (toxicography), and the knowledge about the treatment of poisonings (clinical toxicology). The term 'toxinology' is not generally accepted.

• Venoms are mixtures of toxins produced and used by animals for their defense. They are specifically designed for the poisoning of individuals of other species. Venoms are purposefully applied to target organisms using specific tools like teeth, other mouthparts, or stings.

• Poisoning is the process in which an organism becomes intoxicated by an exogenous substance.

• Toxicosis is any kind of disease condition caused by poisoning.

• Envenomation is the process of venom application by venomous animals to target organisms, mostly by biting or by stinging.

• The clinical pictures of poisoning in humans are also called intoxications or toxicoses (e.g., mycotoxicoses). If they are due to the exposure to mixtures of different toxins, they are also referred to as polyintoxications.

• Toxicity is the extent of the poisonous effect. It is determined by

  • the type of substance;

  • the amount of the substance administered in relation to the body weight (BW) of the affected living being;

  • the mode of application into the organism: peroral, percutaneous, intramuscular, intravenous, intraarterial, rectal, by inhalation;

  • in case of local application, the duration of exposure and the sensitivity of the affected individual (there are significant differences in toxin sensitivities between children and adults, females and males, and humans and different animal species);

  • the frequency and time course of toxin intake designated as

    • acute toxicity: adverse effects occurring following a single exposure or multiple exposures in a short period of time (<24 h) manifested within 14 days upon administration;

    • subacute toxicity: adverse effects following multiple toxin exposures (13-40 doses over a period of 14-28 days);

    • chronic toxicity: adverse effects following long-term exposure to multiple doses of toxins that have per se no acute toxicity;

    • subchronic toxicity: adverse effects occurring during a treatment regime of 90 daily doses that have per se no acute toxicity;

    • long-term toxicity: adverse effects that become manifest only after a long latency period, mainly mutagenic and carcinogenic effects (see later).

• Thus, the designation of a substance as a poison or toxin depends on many variables and is not to be understood as an absolutum.

• Habituation is the development of tolerance for a poison upon frequent exposure to doses of a poison that has per se no acute toxicity (also designed as mithridatism).

• Addiction is the overwhelming desire or need to continue the use of a substance after habituation.

• Withdrawal syndrome is a term to describe a group of symptoms occurring upon abrupt discontinuation of intake of a medicine, a narcotic substance or a toxin after development of addiction.

• Toxicological relevance is a term which describes the likeliness of exposure of humans or animals to a certain poison.

• Toxification means that a substance, nontoxic in its native form, is converted into a poison by biotransformation in an organism.

• Detoxification means the conversion of a poison to a nontoxic substance by biotransformation in an organism.

• Mutagenicity is the ability of a substance, a mutagen, to promote the occurrence of mutations, i.e., to induce changes in the nucleotide sequence of the DNA in cells or organisms.

• Carcinogenicity is the potential of a substance, a carcinogen, to provoke the development of cancer. Primary carcinogens have a carcinogenic effect without metabolic activation. Secondary carcinogens are noncarcinogenic precursors which must be transformed into effective carcinogens in the organism's metabolism. Most natural carcinogens, e.g., aflatoxins or pyrrolizidine alkaloids, are secondary carcinogens.

• Tumor promoters are substances that promote tumor growth but are not carcinogens themselves.

• Teratogenicity is the capacity of a substance, a teratogen, to induce irregularities in the embryonic development causing malformations in the structure or function in the offspring or fetal or embryonic mortality.

• Phototoxins are substances that cause deleterious photosensitivity of the skin or other external organs.

• Phytotoxins are toxins produced by parasitic microorganisms that are directed against plants and cause chlorosis (bleaching), wilting, malformations of the plant, or its death. Substances that are covered by this definition are not considered in this book series. However, the term phytotoxins is sometimes used to describe toxic peptides and proteins produced by plants and directed against other organisms, e.g., as defensive chemicals. Such toxins are considered in this book series.

In the present series of our books, only those natural poisons are considered which are capable to cause adverse effects in animals and humans. Interesting toxins that are harmful to microorganisms, fungi, or plants are mentioned but not comprehensively discussed.

1.2 History of Natural Poisons

Our knowledge about poisonous plants, mushrooms, and animals is as old as mankind itself. It was acquired in the course of exploration of the environment through accidental discoveries at the cost of many sacrifices. Some of them have already been made by our animal ancestors.

Every adult wild animal 'knows' dangerous plants and poisonous animals in its familiar environment. Poisoning occurs in animals only when they encounter poisonous plants in an unfamiliar form, e.g., in hay, when...