3. TOXICOLOGY
Toxicology is derived from Greek words “toxicos” meaning
poison and “logos” meaning knowledge.
“It is a study of adverse effects of chemicals on living
organisms, in other words it is a study of symptoms,
mechanism , treatments and detection of poisoning
especially the poisoning of peoples. Chief criteria regarding
the toxicity of the chemicals is dose.”
4. PLANT TOXINS
Plant toxins are toxic secondary plant metabolites which naturally occur in food,
feed, weeds and ornamental plants.
Toxicity Class
• Major Toxicity: These plants may cause serious illness or death.
• Minor Toxicity: Ingestion of these plants may cause minor illnesses such as
vomiting or diarrhea.
• Oxalates: The juice or sap of these plants contains oxalate crystals. These
needle-shaped crystals can irritate the skin, mouth, tongue, and throat, resulting
in throat swelling, breathing difficulties, burning pain, and stomach upset..
• Dermatitis: The juice, sap, or thorns of these plants may cause a skin rash or
irritation. Wash the affected area of skin with soap and water as soon as possible
after contact. The rashes may be very serious and painful..
5. Poisonous plants:
A poisonous plant is one which, as a whole or a part thereof; under all or certain
conditions, and in a manner and in amount likely to be taken or brought into contact
with an organism, will exert harmful effects or cause death either immediately or by
reason of cumulative action of the toxic property, due to the presence of known or
unknown chemical substances in it, and not by mechanical action.
Classification of poisonous plants:
Poisonous plants can be classified in a number of ways; however the most common
classifications are:
• Based on active chemical constituents
• Based on physiological action
• Based on taxonomical system
However, they can also be classified based on the poisonous parts (bark, root, leaves,
seed etc.) of the plant.
6. CLASSIFICATION OF PLANT
TOXINS
Plant toxins are classified on their structural and chemical
properties as follows:
a) Alkaloids :
These are organic compounds containing nitrogen in
heterocyclic ring, basic in nature and derived from amino
acid, most of which exhibit strong physiological activity. For
example, colchicines, nicotine, aconitine, taxine, cocaine
and many other.
Some common toxins from this class include:
Indole Alkaloids, Pyrrolizidine, Tropanes, Glycoalkaloid etc.
7.
8. b) Glycosides:
Some common toxins from this class include:
Cyogenic glycosides, Cardiac glycosides, Goitrogenic glycosides,
Mustard seed oil glycosides etc.
9. c) Tannins :
These substances have the capability to precipitate
proteins. They make the skin tough by deception of
the proteins in the skin.
d) Proteins :
A few protein toxins produced by plants enter
eukaryotic cells and inhibit protein synthesis
enzymatically. Examples of poisonous proteins include
ricin (castor plant), abrin (rosary pea) and white
acacia. Lathyrism occurs due to a toxic amino acid.
10. e) Volatile oils :
Volatile oils are liquid substances formed in special oil cells,
glands, hairs, or channels. They are all soluble in alcohol. At
certain concentrations, some are irritant (forming blisters) and
emetic. Some volatile oils are nephrotoxic.
f) Oxalic acid and oxalates :
These substances may be present in trichomes or in raphides
(needle-like structures). They can provoke mechanical irritation.
Ingested oxalate will be absorbed. Oxalate in blood binds
calcium to form the insoluble calcium oxalate. Severe
hypocalcaemia with tetany can occur. (Tetany is a symptom that
involves involuntary muscle contractions)
11. PLANT TOXICITIES IN HUMANS
AND ANIMALS
1.The seeds of certain plants like aristida may pierce the skin giving rise to
subcutaneous or intramuscular abscesses. These seed have bored into the salivary
ducts of the cattle and caused injury. This action is purely mechanical, so it cannot
be termed as poisonous plants.
Fig: Aristida plant
2. All parts of the plant may not be poisonous. Seed of family Rosacea contain
dangerous amount of prussic acid but the outer fleshy portion of the fruit is eaten.
12. 3. Certain plants are poisonous to one species and the same quantity may not
affect the other species. Example; Belladonna is poisonous to most species
but rodents like rabbit can have it in large quantities.
Fig: Belladonna Fig: Senecio
4. Some plants if eaten affect only a particular organ of the body. It does not
cause serious body harm but render the organ unable to carry on their
normal functions, e.g. Senecio of sunflower family causes hepatic cirrhosis in
man and animals and prevent the liver from carrying out its normal
functioning
13. 5. Certain plants loose their toxicity on being dried or cooked, e.g. species of
Ranunculaceae is toxic in green state but can be used as food when dried.
6. Certain plants provide food but under certain conditions produce varying
amount of poisonous substance, e.g. potato is a vegetable but at time of
sprouting produces dangerous amount of solanine.
7. Certain plants like khesari (Lathyrus sativus) give rise to pathological
conditions when fed in large doses for prolonged use.
Fig: Sprouting potatoes Fig: Lathyrus sativus
14. 8.Pyrrolizidine alkaloids are among the most significant plant chemicals
causing disease in animals and humans. After absorption from the gut, the
compounds are converted to electrophilic pyrroles in the liver which, apart
from causing damage to this organ, may escape to cause injury to extra
hepatic tissues such as the lungs, heart, and kidneys.
15. 9) Consumption of cycad plants by cattle may cause a neurotoxicity characterized
mainly by a posterior sensory ataxia.
کنگھی
پام
Fig: Cycad plant
10) Many legumes contain phyto-oestrogens, notably isoflavones. Consumption of
these compounds at high levels by sheep can cause extensive lesions of the genitalia
of females and castrated males.
16. HIGHER PLANTS,
• Higher plants, also known as vascular plants, is a large group of
plants that have vascular tissues (with veins) to distribute
resources through the plant.
18. TOXICITY OF ESSENTIAL OILS
TERPENE:
I. Cineol
• Botanical source : Eucalyptus glublus
• Family : Myrtaceae
• Part used: Leaves
• Toxicity: Systemic toxicity can result from
ingestion or topical application at higher than
recommended doses. The probable lethal
dose of pure eucalyptus oil for an adult is in
the range of 0.05 mL to 0.5 mL/per kg of body
weight. Severe poisoning has occurred in
children after ingestion of 4 mL to 5 mL of
eucalyptus oil.
19. 2: Pine oil
Botanical source : Pinus sylvestris
Part used: Seed
Family: Pinaceae
Chemical composition: The main chemical constituents of pine
oil are borneol, bornyl acetate and b-phallandrene, alpha and
beta - pinene and 3-carene.
Toxicity: Pine oil has a relatively low human toxicity level,
however, it irritates the skin and mucous membranes and has
been known to cause breathing problems. Large doses may
cause central nervous system depression.
MONOTERPENES:
1: Thujone
Botanical source : Artemisia absinthium
Family: Asteraceae
Part used: Leaf & flowering top constituents
Borneol
Bornyl
acetate
20. Chemical constituents: The hydro distilled essential oil of the aerial parts
mainly contain caryophyllene oxide , p-cymene,1,8-cineole and (Z)-lanceol
acetate .
Toxicity: Thujone is reported to be toxic to brain, kidney, and liver cells and
could cause convulsions if used in too high dose. In extreme quantities,
thujone is toxic and may cause hyperactivity, excitability, delirium, seizures or
worse
II Menthafuran
Botanical source : Mentha pulegium
Family: Lamiaceae
Common name: Pennyroyal
Part used: Leaves
Common name : Pennyroyal
Toxicity: Menthofuran is an organic compound found in a variety of essential
oils including that of Pennyroyal. It is highly toxic and believed to be the
primary toxin in Pennyroyal responsible for its potentially fatal effect. After
ingestion of menthafuran,it is metabolically activated to chemically reactive
intermediates that are hepatotoxic
P- cyamine
Menthafuran
21. PHENYL PROPANE:
i: Apiol
Botanical source : Petrosileum hortense
Family : Apiaceae
Part used: Leaves
Toxic effects: The toxic dose is difficult to define, because it
depends on the mode of preparation and on the association
with other substances that can enhance the toxicity of the
product. But the facts that patient ingests an exceedingly
large dose of the drug in a short period of time may help to
enhance the severity of the symptoms. Patients show a
bleeding tendency associated to thrombocytopenia and an
anemia, hematuria, Fatty liver and necrosis and
demyelination of peripheral nerves. All the cases reported
would tend to show that the process is limited to the
peripheral nerves and there is no involvement of the CNS.
22. Ii: Safrol
Botanical source: Pimpinella anisum
Family: Umbelliferae
Part used: Root bark or fruit
Toxic effects:
I. Following the ingestion of sassafras oil symptoms can include vomiting,
vertigo and pallor which can appear within 10 to 90 minutes. Excessive
consumption of tea prepared from the roots of the shrub sassafras has
produced sweating.
II. It was also used as a tea. But sassafras tea contains a lot of safrole, the
chemical in sassafras that makes it poisonous.
III. One cup of tea made with 2.5 grams of sassafras contains about 200 mg
of safrole. That equates to a dose of about 3 mg of safrole per 1 kg of
body weight. This is about 4.5 times the dose that researchers think is
poisonous. So, in 1976, the US Food and Drug Administration (FDA)
ruled that sassafras could no longer be sold as sassafras tea.
Safrol
vertigo
23. Iii: Myristicin
• Myristicin is found in spices and herbs such as nutmeg, black pepper, carrot, parsley
Nutmeg abuse : As narcotic.
tachycardia,
salivation
CNS excitation
PLANT ACIDS:
1: Oxalic acid: The term "oxalic acid" is formed from the Latin word oxalis, which
refers to plants with leaves similar to clover. It is important to note that the leaves of a
plant almost always contain higher oxalate levels than the roots, stems, and stalks.
• Fruits - blackberries, blueberries, strawberries, kiwifruit, Oxalic acid concord (purple)
grapes, figs, tangerines and plums
• Vegetables - spinach, Swiss chard, beets (root part), beet greens (leaf part), parsley,
leeks and quinoa are among the most oxalate-dense vegetables. Nuts and seeds -
almonds
24. Toxicity:It has been reported that the lethal oral dose is 15 to 30 grams. toxicity of
oxalic acid is due to kidney failure caused by precipitation of solid calcium oxalate, the
main component of kidney stones. Oxalic acid can also cause joint pain due to the
formation of similar precipitates in the joint , there is a possible risk of congenital
malformation in the fetus; may be harmful if inhaled, and is extremely destructive to
tissue of mucous membranes and upper respiratory tract; harmful if swallowed;
harmful to and destructive to tissue and causes burns if absorbed through skin or is in
contact with the eyes
Oxalic acid
25. PLANT ACIDS
2: Amino acids:
• Proteins are polymerized residues of amino acids
• The number and proportion of AA vary from protein to protein
• When proteins are denatured, the AA remain
• To study protein, you must study AA
• At least 30 different AA, some essential others non-essential
• Most AA are made using short-chain fatty acids (FA; such as
acetic, proprionic or butyric acid)
• Naturally-occurring have L-configuration
• Synthetic have large proportion of D configurations
27. Amino acid Quality:
Amino acids divided into two groups:
• Essential
• Non-Essential
AMINO ACID TOXICITY:
• Toxicity/antagonisms are result of dietary imbalances in EAA
• when one EAA is fed in excess it can also increase the requirement for another,
structurally-similar EAA
Toxicity
overfeeding of one EAA and negative effects not mitigated by increasing other EAA
• Gastrointestinal distress, such as bloating
• Abdominal pain
• Diarrhea
• Increased risk of gout (build up of uric acid in the body, leading to joint
inflammation)
• Unhealthy drop in blood pressure
• Changes in eating patterns
• Need for your kidneys to work harder to maintain balance
ESSENTIAL
AMINO ACID
• lysine (LYS)
• arginine (ARG)
• methionine
(MET)
• histidine (HIS)
• isoleucine
(ILE)
• leucine (LEU)
• threonine
(THR)
• tryptophan
(TRY)
• phenylalanine
(PHE)
• valine (VAL)
28. AMINO ACID ANTAGONISM
3: Resin acid
• Resin acid refers to mixtures of several
related carboxylic acids,
primarily abietic-type acid and pimaric-type acids
Toxicity : It can cause :
•Carcinogenicity, Reproductive developmental toxicity,
•Neurotoxicity, Contact dermatitis,
•Eye irritation
•Nose irritation
•Throat irritation
•Asthma
•Changes in lung function.
Pimeric acid
29. GLYCOSIDES
1: Cardiotonic glycosides:
Agents that have a strengthening effect on the heart or that
can increase cardiac output.
• Biological source: Digitalis purpuea
TOXICITY:
• An irregular heartbeat that causes dizziness, feeling that the heart has skipped a
beat, shortness of breath, sweating or fainting.
• Hallucinations, confusion and mental changes like depression.
• Trouble with eyesight, such as blurry eye sight, double vision, seeing yellow, green
or white halos around objects.
• A loss of appetite or an upset stomach.
• It frequently causes vomiting, anorexia and diarrhea.
Digitalis pupurea
30. 2: Cyanogenic glycosides:
• Cyanogenic glycosides serve as important chemical weapons in the defence of the plant
against herbivores because of the potential to generate toxic hydrogen cyanide
• Amygdalin is the most common of the cyanogenic glycosides
• Present in abundance in the seeds and kernels of fruits such as apricot, almond, apple, cherry,
plum, peach and nectarine
Toxicity :
Occur in humans at doses between 0.5- 3.5 mg kg-1 body weight . When cyanogenic plants
are ingested by humans, enzymes produced by the intestinal microflora are able to
hydrolyse intact cyanogenic glycoside to produce hydrogen cyanide in vivo.
Symptoms :
Headache, nausea, vomiting, abdominal pain, dizziness, weakness, mental confusion,
convulsions, cardiac arrest, circulatory and respiratory failure, coma and in extreme cases
death
31. ALKALOIDS
• Alkaloids form the most important group of vegetable base. These are complex heterocyclic
nitrogenous compounds having a basic nature and are mostly tertiary amines. These have profound
physiological action and in many cases are of intense poisonous nature.
• These plants contain bitter taste and sufficient protection from being eaten by cattle. Some of the
poisonous alkaloids are—aconitine from aconite root, morphine from poppy capsules, emetine from
ipecachuanha root, strychnine from nux vomica seeds, nicotine from tobacco leaves, curarine from
curare, etc
1: Imidazole
Biological source: Jaborandi leaves (Pilocarpus microphyllus and P. jaborandi)
Toxicity
• high level of amino transferase enzyme and hepatocellular toxicity
• Renal toxicity
• Eye toxicity by damaging cornea and retina.
Imidazole alkaloid
32. 2: Pyrrolizidine
Biological source: Senecio and Crotalaria spp
Pyrrolizidine alkaloids are among the most significant plant chemicals causing disease in animals
and humans. After absorption from the gut, the compounds are converted to electrophilic
pyrroles in the liver which, apart from causing damage to this organ, may escape to cause injury
to extrahepatic tissues such as the lungs, heart, and kidneys
Senecio vulgaris Crotalaria jucea
33. 3: Tropane:
Biological source: Datura stramonium, Atropa belladonna
Toxicity :
The toxicity (anticholinergic effects) of Solanaceae plants can
be attributed to their tropane alkaloids content and profile
(i.e., the relative amount of atropine, hyoscyamine, and
scopolamine), which can differ greatly between species,
geographical regions, and harvesting stages . All parts of the
plants are toxic, including the flowers, seeds (fruits), leaves,
and stems.
Tropane alkaloids compete with acetylcholine for binding sites
on the muscarinic receptors, producing both peripheral (e.g.,
dilated pupils, blurred vision, hyperthermia, dry mouth, dry
flushed skin, tachycardia, reduced bowel motility, and urinary
retention) and central (e.g., hallucinations, delirium,
drowsiness, amnesia, ataxia, seizures, and coma) effects.
Their toxicity is dose-dependent, with more profound effects
as the dose increases.
Tropane skeleton
Flushed skin
