This document discusses the classification, identification, and chemical constituents of poisonous plants. It outlines several categories of toxic plant compounds including alkaloids, terpenes, glycosides, proteinaceous compounds, organic acids, and resins. Specific poisonous plants and their toxic principles are provided as examples for each compound category. The document serves as an introduction to plant toxicology and identification of poisonous plants.

1. CLASSIFICATION,
IDENTIFICATION &
CHEMICAL
CONSTITUENTS
OF POISONOUS PLANTS
Dr. Sindhu K
M. V. Sc. Scholar, Dept of VPT,
COVAS, Pookode.

2. INTRODUCTION TO PLANT TOXICOLOGY
Toxic plant may be defined as “one which detrimentally affects the health of
man or animal when eaten in such amount as would be taken normally or under
special circumstances like restriction of choice of diet or extreme hunger”.
The toxic (active) principles present in the plants = PHYTOTOXINS.
The basic framework of protoplasm = Amino acids (20)
Pathway of metabolism Primary metabolites  glucose, AA.
Secondary metabolites  alkaloids,
glycosides,
terpenes, resins.

3. SECONDARY PLANT METABOLITES
{SPM}
Plant toxins may be referred as SPM.
SPM  defense mechanism / survival adaptations.
Toxic plants are of 2 types
i. Plant containing toxic ingredients & are known to be toxic to animals.
ii. Plants which are normally not toxic to animals but becomes so under
unfavorable conditions.

4. CLASSIFICATION OF
TOXIC PLANTS
I. Alkaloids
II. Terpenes
III.Glycosides
IV. Proteinaceous compounds
V. Organic acids
VI. Resins & Resinoids

5. ALKALOIDS
Complex nitrogen containing
organic compounds having one/more heterocyclic rings.
Alkaline in nature.
Readily soluble in alcohol, but sparingly soluble in water.
Both alkaloids + alkaloid salts precipiated by tannic acid &
oxidized by potassium permanganate.
Bitter in taste & often poisonous.
Name ends with suffix –ine.
Eg: atropine, epinephrine, ergotamine, apomorphine.

6. TROPANE/ATROPINE LIKE
ALKALOIDS
Atropine
Datura (jimsonweed)
Erythroxylum (coca tree)
Hyoscyamus (henbane)
Mandragora (mandrake)

7. PYRROLIZIDINE ALKALOIDS
Retronecine
Senecio (ragwort)
Crotalaria sp.
Heliotropium sp.
Trichodesma sp.

8. PYRIDINE/PIPERIDINE ALKALOIDS
Conium (Hemlock)
Lobelia (Indian tobacco)

9. PYRROLIDINE-PYRIDINE
ALKALOIDS
Nicotine
Nicotiana sp. (Tobacco)
Equisetum sp. (Horse tail)

10. PURINE ALKALOIDS
caffeine
Coffea sp. (Coffee)
Theobroma sp. (Cocoa)
Camellia sp. (Tea)

11. QUINOLINE ALKALOIDS
Quinine
Cinchona sp. (Quinine tree)
Echninops sp. (Globe thistle)

12. ISOQUINOLINE ALKALOIDS
Morphine
Papaver somniferum
(opium)
Sanguinaria sp.
Dicentra (Blood root)

13. INDOLE/
INDOLIZIDINE ALKALOIDS
Strychnine
Strychnus (strychnine)
Claviceps (Ergot)
Psilocybe (Magic mushroom)
Astragalus sp. (locoweed)
Gelsemium sp.

14. QUINOLIZIDINE ALKALOIDS
Anagyrine
Laburnum sp. (Golden chain)
Baptisia sp. (False indigo)
Cytisus sp. (Scotch broom)

15. STEROIDAL
GLYCOALKALOIDS
Solanidine
Lycopersicum sp. (Tomato)
Solanum sp. (Nightshades)

16. STEROIDAL ALKALOIDS
Jervine
Veratrum sp.
Zigadenus sp.

17. DITERPENOID ALKALOIDS
Aconitine
Delphinium sp. (Larkspur)
Aconitum sp. (Monkshood)

18. PHENYLAMINE ALKALOIDS
Ephedrine
Lophophora sp. (peyote)
Ephedra sp.

19. TERPENES
Biosynthesized by plants
Contains the branched 5-carbon skeleton of isoprene.
On the basis of number of isoprene units present in the
structure of the molecule, terpenes are categorized as
C-10 compounds  monoterpenes
C-15 compounds  sesquiterpenes
C-20 compounds  diterpenes
C-30 compounds  triterpenes

20. MONOTERPENES
• Cantharidine  an animal monoterpene
from fly ash.
• Picrotoxin from Anamirta cocculus
(Fish berries).

21. SESQUITERPENES
• Coramyrtin from Coriaria myrtifolia
• Geigerin from Geigeria
• Helenalin from Helenium microcephalum

22. DITERPENES
• Andromedotoxin
• Mezerein
• Aconitine from Aconitum sp.

23. TRITERPENES • Cicurbitacins (toxic principles of bittergourd)
• Lantadenes from Lantana sp.

24. GLYCOSIDES
Complex organic compounds having glycone attached to
aglycone/genin moiety by ether linkage
Neutral in reaction
Soluble in alcohol, less soluble in water & insoluble in ether
They don’t combine with acids to form salts
Names ends with suffix –in.
Eg: digitoxin, ouabin, scillarin, glycyrrhizin, senegin.

25. CYANOGENIC GLYCOSIDES
Amygdalin
Amygdalin (Almond seed)
HCN in Hydrangea, Linum
(Linseed)
Prunus (Wild cherry)
Sorghum vulgare (Jowar)
Sorghum sudanese (Sudan grass)
Gossypol (cotton seed)

26. STEROIDAL
(CARDIONILIDES/CARDIAC
GLYCOSIDES)
Digitoxin
Digoxin from Digitalis sp.
Oubain from Strophanthus
Convallarin from Convallaria
Ascleipas (Milk weed)
Nerium oleander

27. STEROIDAL
(SAPONIGENIC
GLYCOSIDES)
Argostemme (Corn cockle)
Phytolacca (Poke weed)
Hedera (English ivy)

28. COUMARIN GLYCOSIDES
Esculin
Ausculus glabra
Moldy Meliolotus sp.
(White sweet clover)
Ipomoea sp. (Sweet
potato)

29. ANTHRAQUINONE
GLYCOSIDES
Cassia fistula (Senna)
Aloe sp.

30. MUSTARD GLYCOSIDES
Sinigrin
Thiocyanates/isothiocyanates
of mustard oil.
(Brasssica nigra)

31. PROTEINACEOUS COMPOUNDS
Plant proteins = harmless + beneficial agents.
Plant protein + seed reserve proteins  important source of food.
Ingestion  protein hydrolysis  enzymatic reactions in GIT 
absorption of amino acids  protein biosynthesis in the body.
However; there are no. of proteins, peptides/amines which are of
toxicological importance.
Eg: toxalbumins, polypeptides, amines.

32. TOXALBUMINS
(PROTEINS)
• Abrin from Abrus precatorius
• Ricin from Ricinus communis

33. POLYPEPTIDES • Amatoxins, phallotoxins &
phalloidin from Amanita sp.

34. AMINES
• Aminotryptaline from seeds of Sativus odoratus
• Phoradendron sp. (Berries of mistle toe)
• Mimosine from Mimosa pudica
• Canavanine from Canavalia ensiformis (Jack beans)
• Leucaena leucocephala (Subabul)

35. ORGANIC ACIDS
Acids accumulated in plants, particularly in their fruits but
are non-toxic.
1. Malic acid
2. Tartaric acid
3. Citric acid
4. Ascorbic acid
But other plant acids possess significant toxic property
solely due to their acidity
Eg: plant oxalic acid & its soluble Na, K or NH4 salts.

36. OXALIC ACID & SOLUBLE SALTS • Oxalic acid
• Potassium oxalate
• Sodium oxalate

37. RESINS & RESINOIDS
Toxic plant resins = phenolic compounds
Important naturally occurring phenolic resin in plants
Exists as amorphous & brittle solids
Insoluble in water, soluble in organic solvents (alcohol, chloroform
& ether)
I. Tetrahydrocannabinol
II. Hypericin
III. Urushiol

38. TETRAHYDROCANNABINOL
• Cannabis sativa
(marijuana or hemp)

39. HYPERICIN • Hypericum perforatum

40. URUSHIOL • Poison ivy
• Poison oak
• Rhus sp.

41. DISCUSSION

42. REFERENCES
Textbook of veterinary toxicology by Harpal singh Sandhu &
Rajinder Singh Brar.
Veterinary toxicology by Satish K. Garg.
Indian medicinal plants (I-IV volumes) by Arya Vaidya Sala.
Google images.