Botanical Name: Strychnos nux vomica
Common Name: Poison nut and dog buttons
● Basically, kuchila grows in Tamil Nadu, Malabar and Uttar Pradesh.
● A vine found in South India.
● These plants bear oval dark green leaves.
● The ripe fruit of this plant contains seeds which are very poisonous.
● Fruits are globular and contain disk-shaped seeds.
● The seeds are round, disk shaped, concave on one side and convex on the other side.
● Seeds are ash gray in color and have a shining surface with short hair.
● The seeds are about 2.5 cm in diameter and 5 mm in thickness.
● The pericarp of seed is tough possess no odour and are very bitter in taste.
● It is used as as rodenticide.
● It is used as vermin killers. Sometimes, it is used for killing stray dogs (hence the name “dog buttons”).
● It is used as folk medicine such as respiratory stimulants, tonics, and cathartics.
● It is used in arrow poison for hunting.
Toxic Parts of Plants
- Root and stem
Order of Toxicity
Leaves < Fruits < Seeds
Seed contains two active principles that are:
● The chemical formula of strychnine is C21H22O2N.
● It is colourless, odourless white crystalline prism that melts at 275 to 285 degree Celsius with decomposition.
● It is very bitter in taste.
● It is more powerful than brucine.
● It is soluble in alcohol but insoluble in water.
● The chemical formula of brucine is C23H26O4N2.
● It is colourless and has prismatic crystalline form.
● It has bitter in taste.
● It is one-eighth times poisonous as compared to strychnine.
Root, stem, bark and leaves contains active principle that are-
- Lagonin as glycoside
● About 30 to 50 mg for strychnine.
● About 1 to 3 grams for strychnos seeds.
The fatal period of kuchila is 1-2 hours.
Absorption, Metabolism and Excretion
● Strychnine is well absorbed from gastrointestinal mucosa and nasal mucosa but not through the skin.
● It is metabolized in liver. In non-fatal human poisoning, strychnine disappearance followed first order kinetics with a half-life of 10 hours to 16 hours.
● It is excreted mainly by kidneys with traces in bile, milk and saliva.
Mechanism of Action
● Strychnine antagonizes the inhibitory neurotransmitter amino-acid glycine at postsynaptic receptors.
● Inhibitory glycine receptors are abundant in the spinal cord and brain stem where they are mainly involved in regulation of motor functions. When inhibitors are blocked, ongoing neuronal excitability is increased and sensory stimuli produce exaggerated reflex effects thus producing powerful muscle contractions.
● Glycine receptors in higher brain centers such as substantia nigra, neostriatum and hippocampus are commonly insensitive to strychnine, explaining why strychnine symptoms are largely spinal in origin.
Sign and Symptoms
● If seeds are swallowed uncrushed, the hard pericarp resist digestion and seeds are passed in feces without any poisonous symptoms.
● With crushed seeds, symptoms begin to appear within 15 to 30 minutes.
● Bitter taste in mouth.
● Sense of uneasiness.
● Fear and anxiety
● Increase difficulty in breathing and swallowing.
● Muscle twitching and spasm of muscle followed by convulsions.
● The convulsions are more marked in anti-gravity muscles and body arches in hyperextension position and lies on heel and head. This position of body is known as opisthotonos. It is most common position. However, at time, the body may bend forward and the condition is called as emprosthotonos. If body bends side wise (i.e. lateral bending), the condition is called as pleurothotonos.
● Contraction of the muscles of face causes widening of the angle of mouth with creases appearing around eyelids. This condition is known as risussardonicus. Also called as sardonic smile due to grimacing that occurred due to muscle contraction of face.
● There is difficulty in breathing during convulsions due to contraction of chest muscles and diaphragm.
● Patient remains conscious and maintains clear sensorium during and between convulsions.
● There may be frothing at mouth.
● Pupils are dilated.
● Death usually occurs due to Medullary paralysis, hypoxia as well as Respiratory failure due to spasm of respiratory muscles
● Patient should be managed in calm environment.
● Induction of Emesis is contraindicated as the procedure may precipitate convulsions.
● Gastric lavage may be carried out after protecting air way.
● Activated charcoal should be administered and is considered as effective.
● Management of convulsions is important and can be treated by lorazepam or diazepam is a good alternative.
● Rest symptomatic measures.
Post Mortem Findings
● Firstly, rigor mortis appear and disappear early.
● Postmortem caloricity.
● Signs of asphyxia.
● Froth at mouth.
● Serosal surface may show hemorrhagic areas.
● Occasionally muscle may show hemorrhages or evidence of rupture.
● Spinal cord is congested. Microscopy shows multiple hemorrhages in anterior and posterior horns with ring hemorrhages around the capillaries.
● Neurons may show chromatolysis.
● Organs are congested.
● Dilated pupils.
● Thin Layer Chromatography gives reliable qualitative results on gastric aspirate, urine, blood, or tissues. The best specimens are urine and gastric aspirate.
●High Performance Liquid Chromatography provides accurate quantitative data.
● Blood levels in the range of 0.1 to 0.3 mg/100 ml are generally lethal.
Samples to be Preserved
- Routine viscera
- Spinal cord
Medico legal Importance
● Accidental poisoning may occur in children who may chew the seeds out of curiosity.
● Accidental poisoning may occur in adults due to consumption of folk/indigenous medicinal preparation.
● Accidental poisoning in adults may occur due to strychnine consumption as it is considered as aphrodisiac.
● Homicide rare due to bitter taste and dramatic appearance of symptoms, however cases have been reported.
● It is also used as cattle poisoning.
● Owing to the agonizing nature of death, strychnine is rarely employed in suicide but has been reported.
Dr. K.S. Narayan Reddy. The essential of forensic medicine and toxicology.34th edition.
VV Pillay. Modern medical toxicology 4th edition.
R.K.Sharma. Concise textbook of forensic medicine and toxicology. 3rd edition.