My brother and I were trying to identify childhood photos. One stumped the both of us, but we were quickly able to identify the plant in the picture. My mother grew the castor bean plants for their beautiful leaves and quick shade. They grew tall around my childhood home. Imagine my surprise at finding castor beans are grown commercially in Peru, one of the leading producers of castor oil!
My knowledge of castor oil was anecdotal, even if I did know the plant by sight. Castor oil was given to children as a punishment in past generations. Many websites and blog posts discuss the use and threat of castor oil to bring a child into submission to his or her parents. The New York Times (April 4, 1884) ran an article they entitled “Substitutions” in which they suggested that if corporal punishments were no longer to be used in schools, that castor oil could be substituted as a punishment.
“So great is the juvenile horror of castor-oil that all parents know that not even the threat of a severe flogging can induce a small-boy [sic] to swallow the nauseous dose … It follows that castor-oil as a punishment in schools is far more to be dreaded than flogging, and should it be generally adopted, small-boys will everywhere petition for the restoration of the rod.”
Castor oil is no longer used to bring unruly children into line, but it is a valuable renewable oil. It is greatly prized in manufacturing and is used, according to Wikipedia, in the production of “lubricants, hydraulic and brake fluids, paints, dyes, coatings, inks, cold resistant plastics, waxes and polishes, nylon, pharmaceuticals and perfumes.”
Castor oil is rich in ricinoleic acid, (more about ricin in a moment) which is a monounsaturated, 18-carbon fatty acid. What makes ricinoleic acid popular in manufacturing its hydroxyl functional group on the 12th carbon, causing it to be more polar than most fats. (Polar refers to the electron configuration around a molecule affecting its miscibility.) The easiest way to understand the value of castor oil is that it has more chemical uses – it can be used to create oils that do not break down in high heat conditions – such as motor oils, but it can also be used to create water soluble oils, or conversely, oils that never dry out. This great versatility translates to a high market price for the oil – almost three times the value of a soy oil or canola oil.
However, I remember the dire warnings my mother had given me as a child. The seeds were dangerous! A neighbor child, even after hearing these warnings, plucked and ate a bean before my mother could stop her. I remember the horror of her parents and the rush to the hospital to have her treated (and the aftermath where my mother was pressured to pull up her castor bean hedge) I came to think of the plant as a pariah, something that people did not want, even if it were beautiful.
The castor bean, besides being rich in a marvelous oil, is also the source of ricin, a rat poison. The poison works through the binding to the cells through pathways that are ubiquitous to eukaryotic cells, entering the cell through its own networks, where it may be discovered by the cell, but ricin is immune to the cells defenses. Ricin then blocks the production of necessary proteins. In humans, death may occur in 36 – 72 hours according to the CDC, dependent on the method of exposure.
Poisons are also the stuff of mystery and mayhem, and more than one murder mystery villain used ricin as their lethal weapon. However, in 1978, George Markov, a Bulgarian writer the victim of such a crime. He was waiting at the bus stop when he felt a prick in his leg. He turned to see a man folding up an umbrella, and leaving the scene by taxi cab. Three days later, it was determined that he was dead due to the injection of a ricin pellet.