rycyna

Rycyna, known in English as ricin, is a highly toxic protein derived from the seeds of the castor oil plant, Ricinus communis. It is classified as a type 2 ribosome-inactivating protein, consisting of two linked polypeptide chains: A, an enzyme that inactivates ribosomes, and B, a lectin that binds to cell surfaces and facilitates entry. By inhibiting protein synthesis, ricin can cause cell death and organ damage.

Exposure to ricin can occur through ingestion, inhalation, or injection. Ingestion typically leads to severe gastrointestinal symptoms such as vomiting, diarrhea, abdominal pain, and dehydration; inhalation can cause respiratory symptoms, including cough, fever, chest tightness, and pulmonary distress; injection can produce rapid systemic toxicity. The severity and outcome depend on the route and dose, as well as individual factors. There is no widely available antidote; medical care is supportive, with decontamination and symptom management as priorities.

Ricin has been studied for medical and research purposes but is tightly regulated due to its potential for harm. Under international law, it is listed as a Schedule 1 toxin, and possession, production, or transfer is strictly controlled. The toxin has appeared in criminal cases and bioterrorism concerns; a well-known historical reference is the assassination attempt on Bulgarian dissident Georgi Markov in 1978, reportedly involving a ricin-containing delivery mechanism.

Public health and forensic laboratories monitor for ricin exposure and employ specialized detection methods. Public information emphasizes risk awareness, proper handling of castor beans, and adherence to legal restrictions to prevent misuse.