Castor

Scientific Name(S): Ricinus communis L. and R. sanguines L. Family: Euphorbiaceae

Common Name(S): Castor, Palma Christi, Tangantangan oil plant, African coffee tree, Mexico weed, wonder tree, Bofareira.

Botany: A common annual ornamental whose native habitat is in the West Indies, the castor grows to heights of 40 feet, bearing broad, deeply lobed leaves on broad stalks. The flowers develop into spiny capsules each containing three seeds. As the capsules dry, they explode, scattering the beans. The castor has been naturalized to temperate regions of the contiguous United States and Hawaii.

History: The name "ricinus" is derived from the Latin word meaning insect, because the seeds resemble some beetles in shape and markings. The plant has been used as an ornamental since antiquity. Castor beans are used as art objects and ornaments. The Egyptians used castor oil as a lamp oil and unguent and ingested the oil with beer as a purgative. The fast-drying, non-yellowing oil is used in industry to coat fabrics, in the manufacture of high-grade lubricants and in dyes and inks. The plant and oil have been used medicinally for an innumerable variety of diseases, rarely with any true clinical benefit.

Uses of Castor

The oil has long been used for laxative effect.

Side Effects of Castor

Ingestion of leaves or seeds is often fatal. Inhalation of residual dust is a hazard to those who handle sacks of castor beans or who work in enclosures where these have been stored.

Toxicology: The castor is a commonly cultivated plant. Ornamental use of the seeds increases the likelihood of toxicities since the beans usually have been drilled, rupturing the seed coat and exposing the contents. If the seeds are swallowed without chewing, poisoning is unlikely because the impermeable seed coat remains intact.

The minimal lethal dose (given IP) in mice is 0.028 mcg crude ricinlg of body weight. As few as one or two chewed beans are lethal to humans. Although the seeds are most toxic, the leaves also may induce poisoning. Toxicity is characterized by burning of the mouth and throat, severe stomach pains, dull vision, renal failure, uremia and death. Treatment is similar to that of other phytotoxin poisonings and generally consists of supportive therapy. Ricinine causes nausea, vomiting, hemorrhagic gastroenteritis, hepatic and renal damage, convulsions and death.

It should be noted that more recent analyses of clinical data from confirmed castor poisonings suggest that ingestion of castor seeds may not always result in severe toxicity. In one event, more than nine school children ingested the seeds without any signs of toxicity. In another more dramatic case, a 38-year-old woman ingested not less than 24 beans that had been cut and chopped to insure absorption. She was treated with induced emesis ad remained completely asymptomatic. Regardless of these more recent successful experiences, castor poisoning always should be treated as a serious medical emergency.

The castor has been implicated as an inhalant allergen. Burlap sacks used in the shipment of coffee beans may be contaminated with castor beans or residual castor pomace this often occurs in the holds of ships or freightcars that have held castor beans. Repeated exposure to castor dust is an occupational hazard to coffee industry workers who handle these sacks.

Summary: Ricin is one of the most potent plant toxins. The widespread cultivation of castor plants represents a potential hazard to small children who ingest and chew the seeds. More recent clinical data suggest, however, that the ingestion of castor seeds by man may not always result in severe toxicity.