DOES IT WORK?:Oleander and its effects on cancer
OLEANDER IS a small tree grown primarily as an ornamental shrub. Also called dogbane, its beautiful clusters of small blossoms led to its other name, the “desert rose”. However, it is also one of the most poisonous plants on earth. The plants are native to the Himalayas, where they are used as a means of suicide.
In recent years, however, extracts of oleander have been advertised on the internet as a cure for cancer. Many reports mention that during the 1990s, over 100 cancer patients in Ireland received a particular oleander extract from their physician. While they are said to have benefited, no details of their outcomes have been published.
The extract used by the Irish patients was developed by a Turkish physician, Dr Ozel. The precise details of how Dr Ozel discovered oleander vary from one report to another. He is said to have noticed that people living at certain elevations in Turkish mountains had lower incidences of cancer. The rates were lowest in those regions where oleander grew naturally and was used by the local people to make a natural remedy.
Dr Ozel produced his own extract of oleander and patented it, calling it Anvirzel. He then conducted research on the extract and eventually tested it on people. Claims abound about remarkable results, but few results are publicly available. The story has different versions after this, involving disputes over at least three companies claiming to have the rights to the remedy. All claim that people benefit from oleander, but that the costs of doing controlled studies have prevented further research.
For many years it has been known that oleander contains several compounds called cardiac glycosides. Similar compounds purified from foxglove (digitalis or digoxin) are used to treat heart failure and other cardiac diseases.
However, the amounts taken by patients must be carefully monitored as the difference between beneficial doses and those causing toxicity is relatively small.
The main cardiac glycoside in oleander is called oleandrin. The plant contains numerous other glycosides, most of which have not been investigated scientifically.
In laboratory tests, oleandrin stimulates the heart and has been found to inhibit the growth of cancer cells grown in laboratories.
After reports were released about cancer patients in Ireland improving with Anvirzel, the manufacturers announced that a phase 1 clinical trial would begin in 2000.
Such studies are short-lasting and designed to determine the safety of drugs and the maximum dose that people can safely tolerate.
The results were published in 2006, involving 18 patients with advanced cancer who were no longer receiving conventional cancer treatments. Patients received Anvirzel by intramuscular injection for between three and 24 weeks. None showed any evidence of their cancer regressing during the study.
The side effects reported were relatively mild, with patients experiencing pain at injection site, tiredness, nausea and breathlessness. Heart problems were not reported.
The phase 1 trial of Anvirzel found that the extract was relatively safe for cancer patients. This is in marked contrast to the fatalities reported when oleander plant material is consumed. Poisonings have occurred in adults and children after ingesting the flowers, leaves or nectar, and even after using the branches as skewers for roasting food.
Symptoms of oleander toxicity resemble those of digitalis toxicity, including nausea, vomiting, dizziness, drowsiness, slow and irregular pulse, and other cardiac effects leading eventually to heart failure. Medical personnel should be informed immediately if oleander is consumed as poisonings respond well to the same treatments used for digitalis toxicity.
Oleander is one of the most poisonous plants known and should not be consumed. As with many other natural products, purified extracts appear to be less toxic.
Given the anecdotal reports, extracts like Anvirzel should be investigated further. However, claims that these extracts cure cancer are premature.
In 2000, the US Food and Drug Administration ordered Anvirzel’s manufacturers to stop making such claims on its website.
Unfortunately, no controlled trials have been published since to provide the necessary evidence to help people make informed decisions about these extracts.
- Dónal OMathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, Dublin City University. He is author of Alternative Medicine: The Christian Handbook, Updated and Expanded Edition, Zondervan, 2007
