Ricin

CAS RN: 9009-86-3

Health Effects

0.2.1 SUMMARY OF EXPOSURE
  • A) USES: Plants containing toxalbumins grow in the wild (mainly in tropical areas) or are used for ornamental purposes (mostly in warmer areas). Seeds (abrin) of Abrus precatorius are brightly colored and used for decorative purposes (eg, bracelets or necklaces). The beans from Ricinus communis (ricin) are a commercial source of castor oil and the remaining powder (pomace) is used as a fertilizer. Castor oil and its derivatives, which are used in a variety of products and extracted from the seeds of the castor plant, have ricin removed as part of the purification process. In addition, the Jatorpha species contain poisonous seeds; the toxin, jatorphin, is a plant lectin (toxalbumin) related to ricin. There are concerns that ricin might be used as a chemical warfare agent.
  • B) TOXICOLOGY: RICIN: Ricin is a protein consisting of 2 approximately equal in size subunits (A and
  • B) bound by disulfide bonds. The B part of the toxin binds to galactose containing receptors in the cell wall, allowing the intact ricin protein to be actively transported into a cell. The A part then inhibits protein synthesis by disabling the 60S ribosomal units. Disruption of protein synthesis inhibition is considered the primary mode of toxicity. Other mechanisms that may contribute include activation of apoptotic pathways, direct cell membrane damage, and release of cytokine inflammatory mediators. ABRIN: Abrin, a toxalbumin that can be found in the seeds of the Abrus precatorius plant acts via a similar mechanism and function to ricin. However, abrin is considered more potent.
  • C) EPIDEMIOLOGY: Exposures in the United States are very uncommon, and severe manifestations are even rarer.
  • D) WITH POISONING/EXPOSURE
    • 1) OVERDOSE: INGESTION: MILD TO MODERATE TOXICITY: CASTOR BEANS or ABRUS SEEDS: Significant toxicity is not expected after ingestion of intact or whole seeds. Nausea, vomiting, diarrhea and abdominal pain may develop. SEVERE TOXICITY: CASTOR BEARS or ABRUS SEEDS: The majority of patients that ingest castor beans or abrus precatorius seeds recover with supportive care. However, there have been reports of severe toxicity. Nausea, vomiting and diarrhea generally develop within hours of severe overdose, and may lead to volume depletion and hypotension. Severe irritation of the GI mucosa may develop, which may result in gastrointestinal hemorrhage and sloughing of tissue. Electrolyte abnormalities may occur. Fever may develop early. Severe exposures may ultimately result in death, reflecting the severe cytotoxic effects of the toxins to the liver, central nervous system, and kidneys. ABRUS PRECATORIUS: Other systemic effects such as hepatic and renal damage, decreased mental status, coma and seizures may be delayed several days after ingestion of Abrus precatorius seeds. INHALATION EXPOSURE: Inhalation exposure to toxalbumins is generally mild. Castor beans do contain an allergen protein that may cause an asthma-like reaction in susceptible individuals. Poison by inhalation of ricin can in rare cases cause systemic symptoms such as fevers and arthralgias and can proceed to respiratory distress and death. DERMAL EXPOSURE: Dermal exposures are generally mild and are due to allergens in the parent plants rather than toxalbumins. EYE EXPOSURE: It may result in mild irritation. PARENTERAL EXPOSURE: Parenteral exposures are very rare and usually intentional. In one case, local tissue necrosis from a ricin injection may have potentiated a bacterial infection. Clandestine injection of a pellet filled with ricin caused a high fever within a few hours, an elevated white count, hypotension and hypothermia, and death 3 days after the original injury.
0.2.3 VITAL SIGNS
  • A) WITH POISONING/EXPOSURE
    • 1) FEVER may be the major and presenting clinical feature; hypotension may also be observed.
0.2.4 HEENT
  • A) EYES: Both miosis and mydriasis have been reported. Retinal hemorrhages may be seen in poisoning. Application of abrin to the eyes may result in mild irritation to loss of eye tissue, depending on the concentration.
0.2.5 CARDIOVASCULAR
  • A) Fast, weak pulse is common. No direct cardiotoxic effects are generally seen. Shock due to fluid and electrolyte loss may occur.
0.2.6 RESPIRATORY
  • A) Castor beans contain an allergen protein that has caused various asthma-like reactions.
0.2.9 HEPATIC
  • A) Liver damage may occur in serious overdoses. Disturbances in carbohydrate metabolism may occur if liver function deteriorates.
  • B) Other hepatic enzymes may also be increased, such as ALT, total bilirubin, AST, alkaline phosphatase, and GGT.
0.2.10 GENITOURINARY
  • A) Hematuria is often seen. Serum creatinine may be elevated.
0.2.13 HEMATOLOGIC
  • A) Toxalbumins are hemagglutinating. Effects in poisoning are minimal, even though the effect is prominent in vitro.
0.2.20 REPRODUCTIVE
  • A) No specific toxicities have been noted in pregnancy of humans. Abrin has been used by herbalists as an abortifacient.
  • B) Birth defects and seizures were reported in an infant born to a young mother who had taken castor oil seed (Ricinus commuis) orally as a contraceptive for 8 weeks after conception.
Find more information on this substance at: PubChem, PubMed