—Barrie Cassileth, PhD
ALSO KNOWN AS: Rose laurel, adelfa, rosenlorbeer, karavira.
SUMMARY: Nerium oleander, an evergreen shrub, is native to the Mediterranean regions of Africa and Europe. It has been cultivated as an ornamental plant throughout the tropical and subtropical parts of the world; it is used in traditional medicine to treat hemorrhoids, ulcers, and leprosy—and as an abortifacient.
All parts of the plant contain compounds called cardiac glycosides, which are known for their toxicity. However, while cardiac glycosides in high doses are toxic, optimal doses can be effective in treating heart conditions. Also, some of these compounds exhibit selective toxicity against tumor cells.
Extracts of oleander are promoted to treat cancer, AIDS, and congestive heart failure, and a few of these extracts are being investigated in clinical trials. There are no data yet on their efficacy. In vitro studies indicate that oleandrin, a cardiac glycoside extracted from the leaves of oleander, causes apoptosis in several cancer cell lines[1-3] and increases the sensitivity to radiotherapy of PC-3 human prostate cells.[4] Results from a phase I study showed that oleandrin can be administered at doses up to 1.2mL/m2/day intramuscularly with no dose limiting toxicities.[5] More research is warranted.
Putative mechanisms of action include improved cellular export of fibroblast growth factor-2 (FGF-2)[1], induction of the Fas gene in tumor cells leading to apoptosis,[6] formation of superoxide radicals that cause tumor cell injury via mitochondrial disruption,[7] and inhibition of interleukin-8, which mediates tumorigenesis.[8] Oleandrin is also claimed to have analgesic properties.[9]
ADVERSE REACTIONS/ CONTRAINDICATIONS: The leaves of Nerium oleander are toxic when consumed.[10] Onset of toxicity occurs several hours following consumption; symptoms can include vomiting, abdominal pain, cyanosis, hypotension, hypothermia, vertigo, respiratory paralysis, and death.[11] Consumption of oleander leaves resulted in the death of an adult diabetic male.[12]
Patients with hypercalcemia, hypokalemia, bradycardia, ventricular tachycardia, or heart failure should not use this product.[11]
HERB/DRUG INTERACTIONS: It has been hypothesized that the cardiac glycosides in Nerium oleander may have an additive effect with digoxin(Drug information on digoxin), resulting in toxicity.
