Oil nut is an evergreen shrub or small tree growing up to 10m in height, with palm shaped leaves up to 30 cm wide. The plant produces greenish flowers with prickly, round pods which contain the seeds.
In Jamaica, the leaves/ are applied externally for relief from headache and toothache. Castor oil, which is extracted from the dried seeds of the has many applications. Castor oil is used as a purgative, to treat skin problems and for the hair. The oil can also be used for sprains, bruises, inflammation and internally for stomach aches.
In the Eastern Caribbean the leaves are heated and used as a poultice. A tea made with oil nut leaves and other herbs is used there to treat gonorrhoea.
In India oil nut leaves are used for swellings, sores and carbuncles. The oil is used as a purgative and for internal inflammations and externally for swollen breasts and dermatitis.
Modern Research & Uses
A lot of research has been carried out on the toxicity of ricin, the active plant chemical in oil nut, which can be deadly if ingested. This has led to the use of immunotoxins from ricin to target cancer cells. In bone marrow transplant procedures, ricin derived immunotoxins have been used to reduce the likelihood of rejection of bone marrow in host patients. These procedures have proven successful in cases where steroids have failed.
Clinical trials into the possible use of these immunotoxins in treating cancerous tumours have been less successful, due mainly to leaking from blood vessels. Research is however continuing in the use of ricin derived immunotoxins in treating cancers and AIDS.
The main plant chemical in oil nut is ricin, which is very poisonous. Ricin is not transferred into the oil made from the seeds. Oil nut also contains alkaloids and glycerides; ricinoleic acid; stearic, linoleic and dihydroxystearic acids, lectins, flavonoids, steroidal sapogenin, gallic acid, and potassium nitrate in the leaves.
One of the main reasons that castor oil is so widely used, is the fact that it does not congeal at low temperatures. Castor oil is used to make soaps, various cosmetics, candles, crayons, varnishes, lubricating oils, high performance fuels, polyamide fibre and leather preservative.
Residue from the oil extraction process is used in the manufacture of fertilizers and the stems can be used to make paper and wallboard.
Research has indicated that one milligram of ricin can kill an adult and that just one seed can kill a child. If the seed of the castor plant is swallowed and the seed coat is not damaged, it can pass through the body without danger. However if the seed is damaged or chewed, ricin will be absorbed into the intestines, which can lead to severe poisoning and death.