ricine

Ricine is a highly toxic protein found in the seeds of the castor bean plant (Ricinus communis), which is native to the eastern Mediterranean region but now grows in tropical and subtropical areas worldwide. The plant is widely cultivated for its oil, castor oil, which is used in various industrial and medicinal applications, including lubricants, cosmetics, and laxatives. However, the seeds themselves remain dangerous due to their ricin content.

Ricin is classified as a type II ribosome-inactivating protein, meaning it inhibits protein synthesis by depurination of ribosomal RNA. This action disrupts cellular function, leading to cell death and systemic toxicity. The protein is heat-stable and resistant to denaturation, making it difficult to neutralize through cooking or processing. Even trace amounts can be lethal, with symptoms including nausea, vomiting, diarrhea, abdominal pain, and, in severe cases, organ failure and death. Ricin has no known medical use and is considered a potential bioterrorism agent due to its ease of production and high lethality.

Exposure to ricin can occur through ingestion, inhalation, or injection. Ingested ricin may take 6–24 hours to produce symptoms, while inhalation can cause rapid respiratory distress. There is no specific antidote, and treatment focuses on supportive care, such as fluid replacement and respiratory support. Ricin is regulated in many countries, and its possession or distribution without proper authorization is illegal.

The plant’s toxicity has been exploited historically in warfare and sabotage, though modern regulations have restricted its misuse. Research into ricin continues in the context of biosecurity, with efforts focused on detection methods and countermeasures. Proper handling of castor beans and their byproducts is essential to prevent accidental exposure.