Plant Poisons of Medico-Legal Importance in India

Three species of Datura are common in India: Datura stramonium (jimsonweed), Datura innoxia and Datura metel. All three carry the same tropane alkaloid mixture: hyoscyamine (which racemises to atropine on extraction), scopolamine and traces of related alkaloids. The seed is the most toxic part, with 2 to 6 mg of mixed tropane alkaloids in a single mature seed. A small handful of crushed seeds produces a full anticholinergic toxidrome lasting 12 to 36 hours.

The mechanism is competitive blockade of muscarinic acetylcholine receptors. The clinical picture is the textbook "mad as a hatter, dry as a bone, red as a beet, hot as a hare, blind as a bat" pentad: agitated delirium, dry mucous membranes, flushed skin, hyperthermia and fixed dilated pupils, with tachycardia, urinary retention, absent bowel sounds and hallucinations. Survivors typically have no clear memory of the episode, which has made Datura a recurring agent in highway robbery cases on the bus and train corridors of Uttar Pradesh, Bihar and the trunk routes south.

The criminal pattern is documented in NCRB filings and series from RML Delhi, KGMU Lucknow and PGIMS Rohtak. The "kind stranger" on a long-distance bus or train offers a snack laced with crushed Datura seed. The traveller drifts into delirium and amnesia within an hour. Wallet, phone and luggage disappear. The traveller wakes in hospital with no memory of the journey and a positive urine screen for atropine and scopolamine. Cases are charged under BNS 2023 Section 125 (administering poison, replacing IPC 328) and Section 309 (robbery, replacing IPC 392). Where death follows, BNS Sections 103 to 105 apply.

Analytical confirmation runs on two tracks. The first is botanical: any seed fragment recovered from gastric aspirate is examined under low power microscopy. Datura seeds are kidney-shaped, 3 to 4 mm long, brown to black, with a finely pitted surface and a notch at the hilum. The second track is chemical: thin layer chromatography of an ammoniacal chloroform extract gives well-known Rf values for atropine and scopolamine, and LC-MS/MS on urine gives picogram-level confirmation with the diagnostic m/z 290.2 and 304.2 transitions.

Treatment is largely supportive. Benzodiazepines control the agitation, active cooling addresses the hyperthermia and a urinary catheter prevents bladder distension. Physostigmine 1 to 2 mg IV is the specific antidote and produces a dramatic reversal, but it is rarely stocked in Indian government hospitals and is reserved for severe central toxicity without QRS widening.

Abrus precatorius, the rosary pea or jequirity bean, is a climbing legume grown across India for its glossy red and black seeds, strung into ornaments, prayer beads and toys. The toxin is abrin, a type 2 ribosome-inactivating glycoprotein related to ricin but several times more potent. The lethal dose by injection is 0.1 to 1 microgram per kilogram, making a single pierced seed potentially lethal if its contents reach the bloodstream.

Three medico-legal patterns recur. First, accidental ingestion by children chewing seeds; the hard coat usually protects the abrin from absorption and intact seeds pass through, but cracked coats are dangerous. Second, occupational injury in jewellery makers who pierce seeds and prick their fingers, producing local necrosis, lymphangitis and systemic shock. Third, the historical "sui" or needle technique, a pellet of seed paste implanted under the skin of cattle (and historically of human victims). The cattle quack tradition in north India has used abrin pellets for livestock insurance fraud since the colonial period; case law from the Allahabad and Patna High Courts goes back to the 1920s.

Oral abrin causes severe gastroenteritis, bloody diarrhoea and delayed multi-organ failure peaking at 48 to 72 hours. Parenteral abrin causes local necrosis and rapid systemic shock. No specific antidote; fluid resuscitation and ICU supportive care are the mainstays.

Cleistanthus collinus, locally Oduvanthalai or "the tree of death", is a small dry-zone tree of the Euphorbiaceae family native to Tamil Nadu, Kerala and Andhra Pradesh. The leaves are boiled in water and the decoction is swallowed; the practice has been a major suicide method in Salem, Erode and Coimbatore since at least the 1960s. The toxins are the cleistanthins, arylnaphthalide lignans that damage the distal renal tubule, producing a type 1 distal renal tubular acidosis with profound hypokalaemia, and inflict diffuse oxidative injury on heart, lung and liver. Mortality between 1970 and 2010, in the peak decades, was reported in JIPMER and CMC Vellore case series at 25 to 50 percent.

The course is stereotyped. Within hours of ingestion the patient develops vomiting, abdominal pain and profound weakness. Serum potassium falls below 2.5 mmol/L. Arterial gas shows a hyperchloraemic non-anion-gap metabolic acidosis. By 24 to 48 hours, hypotension, ARDS and multi-organ failure set in. Death is usually from refractory ventricular arrhythmia secondary to severe hypokalaemia or from respiratory failure.

Analytical confirmation for abrin uses ELISA (commercial anti-abrin kits at CFSL Hyderabad and the NFSU Gandhinagar plant toxin section), LC-MS/MS of marker peptides from tryptic digestion of the A chain, and qPCR of Abrus seed DNA from any recovered plant material. For Cleistanthus the markers are cleistanthin A and B detected by HPLC-DAD with confirmation by LC-MS/MS on viscera and gastric aspirate; assays are run at CFSL Chennai and the Forensic Sciences Department, Government of Tamil Nadu.

Strychnos nux-vomica, locally kuchla and known in older English literature as dog button or poison nut, is a small tree of central and southern India whose disc-shaped grey seeds yield the indole alkaloids strychnine and brucine. The alkaloids act as competitive antagonists at the glycine receptor in the spinal cord, lifting the normal inhibitory brake on motor neurons. The result is a hyperexcitable spinal reflex arc, where every light touch, sound or current of air triggers a sudden generalised tonic spasm. The body arches into opisthotonos, the face twists into a fixed grimace called risus sardonicus, and the patient remains conscious through the spasms.

Death usually occurs within one to two hours of a lethal ingestion, from respiratory muscle failure during a sustained spasm, or from rhabdomyolysis and hyperthermia. The lethal oral dose in adults is 30 to 100 mg of strychnine, roughly half a teaspoon of crushed kuchla seed.

The Indian record on kuchla is long. The Bombay Presidency case of Sundara Devi in the 1840s was a homicidal kuchla case heard before the IPC existed; the Indian Penal Code drafted by Macaulay's commission was not enacted until 1860 and did not come into force until 1862. Through the 20th century strychnine was sold openly as a rodenticide; state pesticide schedules restricted it by the 1990s. Sporadic cases continue in north Indian rural districts where small lots remain in informal trade.

Detection is straightforward. Strychnine and brucine separate cleanly on TLC with iodoplatinate spray and on reverse-phase HPLC. GC-MS or LC-MS/MS confirms identity in viscera, gastric aspirate and urine, with the strychnine product ion at m/z 334.2. The kuchla seed is recognisable on visual examination: disc-shaped, 1.5 to 2.5 cm in diameter, ash grey to pale brown, velvety surface, central depression on one face.

ICU treatment is supportive and effective if the patient reaches care alive. High-dose intravenous benzodiazepines suppress the spinal reflex; where seizures cannot be controlled, neuromuscular blockade with intubation is used. Active cooling addresses hyperthermia. The patient is nursed in a darkened, quiet room because external stimuli precipitate spasms. Reported survival in Indian and Sri Lankan series is 60 to 80 percent if airway control is established before the first fatal spasm.

Cerbera odollam, the yellow oleander or pinnambuli, is a small evergreen tree of the Apocynaceae family that grows along brackish waterways in coastal Kerala, Tamil Nadu, the Sundarbans of West Bengal and parts of the Konkan. The green fruit ripens to a fibrous brown drupe enclosing a single woody seed about the size of a walnut. The kernel contains cardenolide cardiac glycosides, principally cerberin and neriifolin. The mechanism is identical to digoxin: inhibition of the sodium-potassium ATPase pump in cardiac myocytes, with secondary effects on automaticity, conduction and serum potassium.

The clinical picture is a cardiac glycoside toxidrome: nausea and vomiting within an hour, sinus bradycardia, AV block, hyperkalaemia and ventricular arrhythmia. Death is from refractory bradyasystole or ventricular fibrillation. The typical Kerala presentation has been a young person, often a woman, who has chewed two to four seeds, presenting with vomiting and a heart rate of 30 to 40.

The Kerala public health record on Cerbera is well documented. An ICMR-supported series from 2006 documented Cerbera as the leading suicide agent in Kannur and Kasaragod districts, with hundreds of deaths per year recorded through 1990 to 2010. Kerala FSD audit reported in-hospital case fatality of 10 to 20 percent. Awareness campaigns and restrictions on roadside plantations have reduced numbers since 2015.

Detection uses LC-MS/MS on serum and urine, with the cerberin precursor at m/z 535.3 and a loss of the digitoxose sugar. Seed fragments are confirmed by microscopy and DNA barcoding. The Forensic Sciences Department of Kerala at Thiruvananthapuram has run a dedicated Cerbera analysis section since the 1990s.

Nerium oleander, the common pink or white kaner shrub of road dividers and temple gardens across north and central India, contains oleandrin and nerioside. The toxidrome is identical to Cerbera. Indian cases include accidental childhood ingestion, suicidal leaf decoctions and rare homicidal addition of crushed seeds to food. LC-MS/MS for oleandrin (m/z 577.3) and the same clinical package (atropine, magnesium, pacing) apply. Thevetia peruviana, sometimes confused with Cerbera in older literature, is a separate species containing thevetin and is managed similarly.

Aconitum ferox and Aconitum napellus, locally vatsanabh and bish, are tuberous herbs of the Himalayan foothills in Uttarakhand, Himachal Pradesh, Sikkim and Arunachal Pradesh. The root is one of the most potent natural toxins in the Indian pharmacopoeia. Aconitine and mesaconitine, diterpenoid alkaloids, bind to and persistently activate the alpha subunit of voltage-gated sodium channels in cardiac and neural tissue, causing sustained depolarisation, neuromuscular block, refractory ventricular arrhythmia and characteristic peri-oral and acral numbness within minutes of ingestion.

The clinical signature is distinctive. Tingling and numbness around the lips, tongue and fingertips arrive within ten to thirty minutes. Nausea, vomiting and salivation follow. Within the first hour the patient develops a bidirectional or polymorphic ventricular tachycardia, often refractory to standard antiarrhythmics. Death from ventricular fibrillation in the first two hours is the classical "aconite cardiac death". The lethal dose of pure aconitine is as low as 2 to 5 mg.

Ayurvedic and Tibetan medicine use processed aconite tuber after shodhana (prolonged boiling in cow's milk, which hydrolyses aconitine to less toxic aconine derivatives). Indian medico-legal cases are usually accidental overdose with unprocessed root taken for joint pain or chronic illness, often from informal village suppliers. The historical European casebook includes the George Henry Lamson case of 1881, an early prosecution in which forensic chemistry distinguished aconitine from common alkaloids.

Detection is routine in the LC-MS/MS era. Aconitine, mesaconitine and hypaconitine separate on reverse-phase HPLC and are confirmed by precursor ions at m/z 646.3 and m/z 632.3 with picogram-per-millilitre sensitivity. CFSL Hyderabad and NFSU Gandhinagar both run validated methods. Treatment is supportive with aggressive arrhythmia management: magnesium sulphate, amiodarone, lignocaine, pacing and ECMO where available. No specific antidote exists.

Ricin, the toxin of the castor bean Ricinus communis, sits in its own category. The castor plant is cultivated across Gujarat, Rajasthan and Andhra Pradesh for castor oil, which is non-toxic; the toxin concentrates in the seed cake after oil extraction. Ricin is a type 2 ribosome-inactivating glycoprotein that depurinates 28S rRNA and arrests protein synthesis. The lethal dose by injection is in the microgram range; oral toxicity is far lower because of poor absorption, but crushed castor seed ingestion still produces severe gastroenteritis and delayed multi-organ failure.

Detection of ricin uses commercial anti-ricin ELISA for rapid screening, LC-MS/MS of marker peptides from tryptic digestion of the A chain, qPCR of the ricin gene from any seed or seed cake material, and immunohistochemistry on tissue sections at autopsy. There is no licensed clinical antidote, although passive immunisation candidates are in development. Treatment is intensive supportive care.

The eight agents above cover the bulk of Indian plant poisoning practice. Other plant-derived agents, including opium, cannabis and capsaicinoids, are covered in the related toxicology topics.

The identification workflow at an Indian FSL plant poisons section runs three tracks. The botanical track examines seed, leaf or root fragments under microscopy: the Datura kidney-shaped pitted seed, the red-and-black Abrus seed, the Cerbera walnut kernel, the kuchla disc-shaped grey seed and the mottled brown castor seed are all recognisable to a trained examiner, with SEM for fine surface detail on fragments.

The chemical track uses TLC with class-specific sprays (Dragendorff and iodoplatinate for alkaloids, Kedde and Baljet for cardiac glycosides), HPLC-DAD for tentative identification and LC-MS/MS for confirmation. Cardiac glycosides require LC-MS/MS because digoxin immunoassays cross-react unreliably. The molecular track uses DNA barcoding (rbcL, matK, ITS), routine at NFSU Gandhinagar and CFSL Hyderabad, and recovers identification when the chemical signature has been lost to cooking, gastric acid or post-mortem degradation.

Interpretation runs through the pathologist and FSL chemist together. Plant alkaloids degrade variably after death: tropane alkaloids and strychnine survive months in viscera; cardiac glycosides degrade faster; aconitine sits in between. The opinion to the court has to state what was detected, what could have been there and degraded, the post-mortem interval, and the chain of custody under BNSS 2023 Section 105 and BSA Section 63. Careful reports set out both positive findings and the limits of negative findings.