See question

Answer: Both!

The castor plant is a beautiful, large semi-woody shrub that can grow to 40-feet tall in the right environment. The star-shaped leaves can grow more than 2.5 feet across. Each lobed leaf has serrated edges and prominent central veins that vary in color from green to red to white. Many species have glossy green leaves; others can be purplish, dark red, or maroon. The stems are often a striking red color.

The female flower develops a bundle of seed capsules, each about the size of a large walnut, which are covered with soft flexible spines after pollination. They have notable colors of coral pink or red that fade to brown with maturity.

To protect and defend themselves from herbivores, some plants develop innate immune systems. These defense mechanisms include lectins and proteins that act to make the threatening animals ill after ingestion, resulting in future plant avoidance.

Properties

The castor plant has been recognized for thousands of years as having properties that can be used for health benefit but may also be harmful. The two major components are castor oil and ricin.

Ricin: The Poison

Castor Bean Plant
Ricinus Communis

Ricin is a poison found naturally in castor beans. A nonmalicious exposure might occur if a castor bean is chewed and swallowed. Mastication releases ricin and causes injury.

Ricin is a natural product that is created from waste material when processing castor beans. It is a heat-labile powder, dissolvable in water or weak acid.

Ricin is a toxalbumin (protein toxin) that is composed of two chains, A and B (the “killer” and the “key”). As a group, they are referred to as ribosome-inactivating proteins (RIPs).

The B chain (key) is a lectin that binds to cell membrane surface glycoproteins and glycolipids, which causes endocytosis and allows ricin to access the cell. Once inside, the A chain (killer) irreversibly inactivates RNA, stopping protein synthesis, leading to cell death.

Ricin is estimated to be 6,000 times more poisonous than cyanide and 12,000 times more poisonous than rattlesnake venom.

One milligram of ricin can kill an adult. The symptoms of human poisoning begin within a few hours of ingestion.

Exposure Route

After ingestion, nonspecific symptoms—including nausea, vomiting, diarrhea, and abdominal pain—develop after approximately 12 hours. Ultimately, this progresses to hypotension, liver failure, renal dysfunction, and may progress to death due to multiple organ failure or cardiovascular collapse. After inhalation, symptoms develop within eight hours and include cough, dyspnea, arthralgias, and fever, which may progress to respiratory distress and death, without other organ system manifestations.

Castor Oil

Castor oil, historically known as Oleum Palmae Christi, comes from the seeds of the Ricinus communis plant and has been used therapeutically for centuries. No ricin is thought to remain in the oil and it would be inactivated during extraction due to heating of the oil.

Castor oil is metabolized to ricinoleic acid, which is absorbed in the intestine. This acts as a strong laxative that has been used medicinally dating back to ancient cultures. Castor oil can also induce labor but has a poor safety profile and thus is not used clinically.

Treatment

There is no antidote and no specific treatment for ricin poisoning. The treatment is supportive for the organs affected.

Interesting Facts

The name Ricinus is a Latin word for tick because the seed of the plant has markings and a bump at the end that resemble certain ticks.

This plant is commonly regarded as one of the most poisonous in the world.

Four seeds can kill an average-sized adult, while ingestion of lesser amounts has resulted in gastrointestinal symptoms and convulsions.

Ricin is suspected to have been the poisonous agent used to assassinate Georgi Markov, a Bulgarian journalist who spoke out against the Bulgarian government, in 1978. He was stabbed with the point of an umbrella while waiting at a bus stop in London. His autopsy revealed a perforated metallic pellet embedded in his leg that presumably contained ricin.

It is advisable to keep children away from the castor bean plant or necklaces made with its seeds.

Ricin has been used experimentally in medicine to kill cancer cells.

Dr. Hack (Oleander Photography) is an emergency physician and medical toxicologist who enjoys taking photographs of beautiful toxic, medicinal, and benign flowers that he stumbles upon or grows in his garden. Contact him at ToxInRI@gmail.com.