Toxic substances

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Last update: Friday, 12 May 2023 at 10.44 pm.

Toxic substances present real risks:

  • causing food intolerance ( intolerance ), toxic for certain individuals,
  • causing intoxication , toxic for all individuals.

Substances causing food intolerance:

  • allergies (immunological reactions), allergens (immunogens), (do not) induce IgE formation,
  • intolerance (non-immunological manifestations), metabolic disorders, hypersensitivity (anaphylaxis), aversion (idiosyncrasy),
    • lactose intolerance, foods with a low content (<10 g/kg), lactose-free (100 mg/kg),
    • phenylketonuria , hydrolysates without Phe,
    • favism, broad bean ( Vicia faba ).

https://www.wikiskripta.eu/w/Soubor:Toxiny-vicin.jpg

Toxins and other substances causing intoxication

Classification:

  • by structure,
  • physical properties,
  • by origin (plant, animal),
  • by effects,
  • main groups of toxins,
  • alkaloids,
  • saponins,
  • cyanogens,
  • glucosinolates,
  • lectins,
  • estrogenic substances,
  • phototoxic substances,
  • amino acids,
  • biogenic amines.

Antinutritional and toxic substances of legumes:

  • protease and amylase inhibitors,
  • α-galactosides,
  • substances causing favism,
  • lectins ,
  • cyanogenic glycosides,
  • estrogens ,
  • saponins ,
  • lathyrogens.

Toxic substances of higher mushrooms:

Alkaloids

Classification:

  • true alkaloids (N-heterocycles, derived from amino acids),
    • pyridine (nicotine) and tobacco,
    • piperidine and pepper,
    • pyrrolizidines and senecias (necines),
    • quinolizidine and. lupins,
    • quinoline and cinchona barks,
  • pseudoalkaloids (N-heterocycles, derived from other precursors),
    • purine a. coffee, tea, cocoa,
    • terpenoid (glycoalkaloids) a. potatoes, tomatoes,
  • protoalkaloids (not N-heterocycles, derived from amino acids),
    • capsaicinoids and peppers.

Pyridine alkaloids

Nicotine and minor alkaloids (~20 compounds):

  • tobacco (obligation to indicate content in tobacco products, warnings).

Pyridinov%C3%A9.jpg

Piperidine alkaloids

Piperine, homologs, geometric isomers, related substances, pepper (hot substances)

Piperidinov%C3%A9.jpg

Pyrrolizidine alkaloids

Many related esters (mono-, di-, macrocyclic), hepatotoxic substances.

Chinolizidinov%C3%A9.jpg

Quinolizidine alkaloids

A number of related compounds, lupine.

Chinolinov%C3%A9.jpg

Quinoline alkaloids

Contents in pod.

Chinolinov%C3%A9.jpg

Legislation: additive, alcoholic beverages 300 mg/l, non-alcoholic (tonics) 75 mg/l (teratogenicity)

Purine alkaloids

a number of related compounds, coffee, tea, cocoa (chocolate), mate, guarana.

Purinov%C3%A9.jpg

  • caffeine R 1 = R 2 = R 3 = CH 3
  • theobromine R 1 = H, R 2 = R 3 = CH 3
  • theophylline R 1 = R 2 = CH 3 , R 3 = H

Steroidal glycoalkaloids

  • a number of related compounds, potatoes, tomatoes, eggplant,
  • heteroglycosides, aglycone, sugar.

Potatoes

  • α-solanine = solanidine + β-solatriose,
  • α-chaconine = solanidine + β-chacotriose,
Solaniny.jpg
  • distribution,
  • legislation: 200 mg/kg.

Tomatoes

  • tomatine = tomatidine + β-lycotetraose
Tomanidin.jpg
  • legislation: 200 mg/kg, teratogenicity

Capsaicinoids

capsaicin, homologues, paprika (hot substances):

  • the effect of technological processing,
  • capsaicin, (E)-8-methyl-N-vanillylnon-6-enamide .

Kapsaicin.jpg

Saponins

a number of related compounds, foods of plant origin:

  • heteroglycosides, aglycone, sugar,
  • aglycon = sapogenin (sapogenol),
    • triterpene alcohols,
    • sterols (4-demethylsterols).

Sojasapogenol-A.jpg

Biological effects:

Properties

  • toxicity to cold-blooded animals,
  • bitter taste,
  • detergent effects, emulsion (o/w),
  • fungicidal, antioxidant, anticarcinogenic, anticholesterolemic effects.

Use

  • foaming agents (cosmetics),
  • emulsifiers (cosmetics),
  • sweeteners (glycyrrhizin, licorice: 0.2−5.6% saponins).
  • Glycyrrhizin.jpg

Cyanogenic glycosides

  • a number of related compounds, foods of plant origin,
  • HCN content in cyanogens,
  • heteroglycosides, aglycone, sugar,
  • aglycone = 2-hydroxynitrile (cyanohydrin),
  • 2-hydroxy acid nitrile.Nitril-2-hydroxykyseliny.jpg

Substituents - Chirality:

  • aliphatic – acetone, methyl (ethyl) ketone,
  • aromatic – benzaldehyde.

Sugar

  • usually Glu,
  • genciobiosis disaccharides etc.
Genciobiosa.jpg

Properties

  • decomposition (β-glucosidase) → HCN, toxicity (inhibition of cytochrome oxidase in the respiratory chain),
  • acute intoxication, chronic intoxication (cassava, cassava).

Glucosinolates

  • thioglucosides (glucosides of mustard oils), a number of related compounds, foods of plant origin (cruciferous plants),
  • names and structure,
  • dominant glucosinolates in vegetables,
    • heteroglycosides, aglycone, sugar, aglycone = thiohydroxamate-O-sulfonate, counterion K+

Glukosinol%C3%A1ty.jpg

Substituents

  • aliphatic,
  • aromatic,
  • heterocyclic.

Sugar

  • exclusively Glc.

Properties

  • decomposition (myrosinase) → isothiocyanates, nitriles, etc.,
  • toxicity, isothiocyanates and goitrin strumogenic, nitriles hepatotoxic.

Vznik-goitrinu.jpg

Plant phenols

estrogenic substances

  • phytoestrogens - foods of plant origin, Estradiol.jpg
    • isoflavones,
    • content in soybeans.
Isoflavonoidy.jpg
daidzin, R = H aglycon daidzein
genistin, R = OH aglycon genistein
soybeans (0.13−0.42%)
    • pterocarps,
    • lignans.
content in food
coumestrol − sprouting − soybeans Kumestrol.jpg
secoisolariciresinol − flax seeds Sekoisolariciresinol.jpg
  • mycoestrogens,
  • xenoestrogens.

Properties

  • simultaneously useful and harmful.

Phototoxic substances

  • coumarins,
  • furanocoumarins,
  • foods of plant origin.
  • Kumariny.jpg

Properties

  • phototoxicity (sensitivity of non-pigmented skin, association with skin cancer, acute dermatitis),
  • phytoalexins (phytonicides, plant antibiotics, pesticides), blastocolins (inhibits seed germination),
  • antimicrobial and other effects.

Phototoxic pigments

  • hypericin (St. John's wort), fagopyrin (buckwheat).

Lectins (phytohemagglutinins)

foods of plant origin (seeds and other parts)

Proteins with a non-catalytic center:

  • merolectins (1 center, catalytic no),
  • hololectins (2 centers, no catalytic),
  • chimerolectins (1−2 centers, catalytic yes).

Soy lectin

  • metalloprotein, 120 kDa, hololectin, N-acetyl-D-galactosamine binding.

Properties

  • precipitation of erythrocytes, interaction with sugars in glycoproteins and glycolipids of membranes (plant protection mechanism against predators, parasites),
  • toxic intravenously, some orally, some not at all, some probiotics (garlic).

Amino acids

Lathyrogens:

  • foods of plant origin (seeds of vetiver and peas),
  • amino acids (peptides, nitriles) -3-(N-oxalyl)-2,3-diaminopropanoic acid Diaminopropanov%C3%A1.jpg

Properties

  • structural form with proteinogenic amino acids, metabolic disorders,
  • deformation of the lower limbs (osteolathyrism), damage to blood vessels (angiolatyrism), disorders of the nervous system (neurolathyrism), humans, mainly farm animals.

Biogenic amines:

  • precursors,
  • aliphatic, aromatic, heterocyclic bases with biological activity, fermented and microbially degraded foods of plant and animal origin

Emergence

  • from amino acids by microorganisms
    • histamine (His) Histamin.jpg, cadaverine (Lys) Kadaverin.jpg

Properties

  • tissue hormones (allergic reactions, anaphylactic shock)
  • psychoactive and vasoactive substances

Content

  • changes in salami

Source