Ricin - Potential Medicinal Use

Potential Medicinal Use

Some researchers have speculated about using ricins in the treatment of cancer, as a so-called "magic bullet" to destroy targeted cells. Because ricin is a protein, it can be genetically linked to a monoclonal antibody to target malignant cells recognized by the antibody. The major problem with ricin is that its native internalization sequences are distributed throughout the protein. If any of these native internalization sequences are present in a therapeutic, then the drug will be internalized by, and kill, untargeted epithelial cells as well as targeted cancer cells.

Some researchers hope that modifying ricin will sufficiently lessen the likelihood that the ricin component of these immunotoxins will cause the wrong cells to internalize it, while still retaining its cell-killing activity when it is internalized by the targeted cells. Generally, however, ricin has been superseded for medical purposes by more practical fragments of bacterial toxins, such as diphtheria toxin, which is used in denileukin diftitox, an FDA-approved treatment for leukemia and lymphoma. No approved therapeutics contain ricin.

A promising approach is also to use the non-toxic B subunit as a vehicle for delivering antigens into cells thus greatly increasing their immunogenicity. Use of ricin as an adjuvant has potential implications for developing mucosal vaccines.

Ricinine has some insecticidal effects on three insect pests as well as a hepatoprotective activity. Ricinine, when administered to mice at low doses has memory-improving effects. The signs of intoxication caused by ricinine can be used as chemical model of epilepsy in the screening of anticonvulsant drugs.