Graviola is a tree indigenous to the rainforests of the Amazon basin and Caribbean islands, where its fruit is enjoyed fresh or used to flavor beverages, ice cream and other foods. The plant is also a traditional medicine in those regions. In recent years, the herb has been promoted as a cancer treatment because it has shown anti-tumor activity in cultured cancer cell samples. No clinical trials in humans exist, however, so efficacy of the supplement form is not established. There are also potential safety issues to consider. You should not use this herb to treat any condition, especially a serious disease such as bladder cancer, without close medical supervision.
Chemical Composition
According to the Memorial Sloan-Kettering Cancer Center, the leaves, bark and stems of graviola, or Annona muricata, contain active compounds collectively called annonaceous acetogenins. Numerous acetogenins have been isolated and identified to date, but the primary graviola acetogenin and the compound most studied is annonacin.
Biological Actions
The active phytochemicals in graviola are lectins, sugar-binding proteins that are widely distributed in plants. The affinity for glucose shown by annonaceous acetogenins appears to be the mechanism responsible for anti-tumor activity. Specifically, these compounds induce tumor cell apoptosis, or cell death, by limiting available adenosine triphosphate, the main source of energy for cell metabolism. In other words, the active ingredients in graviola starve cancer cells to death by cutting off their food supply.
Bladder Cancer
Graviola is reputed to have an effect on all types of cancer cells, including, according to Memorial Sloan-Kettering, multidrug-resistant cancer cells. A study published in the May 9, 2003 issue of "Life Sciences," showed that purified annonacin triggered cell death in various cancer cell lines, including T24 bladder cancer cells. Not only did this substance cause apoptosis in these cells but it also caused them to become dormant during the G1 phase in which cells increase in size to prepare for the replication of DNA before entering the S phase for cell division.
Safety Concerns
Although this herb may have potential as an anti-cancer medicine in the future, there is no guarantee as of 2011 that graviola supplements contain the same active compounds used in research or that they will have the same results in the human body as they demonstrate in a test tube. Also, the results of a 2006 animal-based study published in the "Journal of Neural Transmission" indicate that annonacin crosses the blood-brain barrier and may contribute to the degeneration of basal ganglia and increase the risk of Parkinson's disease and other movement disorders.
References
- Memorial Sloan-Kettering Cancer Center: Graviola
- "Life Sciences"; Annonacin, A Mono-tetrahydrofuran acetogenin, Arrests Cancer Cells at the G1 phase and Causes Cytotoxicity in a Bax- and Caspase-3-related Pathway; S. Yuan, et al.; 2003
- "Journal of Neural Transmission"; Is Atypical Parkinsonism in the Caribbean Caused by the Consumption of Annonacae?; A. Lannuzel, et al.; 2006
