The Healing Power of Rainforest Herbs

What a natural medicine expert says about soursop and cancer

If natural medicine Leslie Taylor is right, soursop — or graviola, as some call it — is a miracle herb that all cancer patients should be consuming as part of their plan to get well.

Taylor is a cancer survivor herself, and after beating leukemia in her 20s she set out to study the extensive catalog of plants found in Amazon rain forests to uncover their medicinal uses that have been

In her book The Healing Power of Rainforest Herbs she summarizes soursop’s medicinal use as follows:

  • Kills cancer cells
  • Relieves depression
  • Slows tumor growth
  • Reduces spasms
  • Kills bacteria
  • Kills viruses
  • Kills parasites
  • Reduces fever
  • Reduces blood pressure
  • Expels worms
  • Lowers heart rate
  • Stimulates digestion
  • Dilates blood vessels
  • Stops convulsions


Soursop dosage from naturopath Leslie Taylor:

Taylor says that the dosage using soursop leaves for any of the conditions above is as follows:

Infusion (Soursop Tea)

1 cup 3 times daily (see also our free soursop tea guide)

Tincture (Concentrate made from soursop leaves or fruit)

2-4 ml 3 times daily.

Note: A tincture is a liquid extract of an herb that you take by mouth. It is a liquid concentration of the useful chemical constituents and medicinal properties of a plant. The liquid is usually alcohol, vegetable glycerin, or even apple cider vinegar. Learn more about how to make a tincture here.

Capsules (powder in capsule form):

2 grams x 3 times daily


Why you should consume soursop when fighting cancer

In her book and on her web site Taylor wrote:

“Many active compounds and chemicals have been found in graviola, as scientists have been studying its properties since the 1940s.”

The research on soursop/graviola has been focused on a plant chemicals called Annonaceous acetogenins.

These natural compounds can be found in sourop’s leaves and stems. It is also present in its bark, fruit, and seeds.

Taylor, who’s book was published in 2005,  said: “Three separate research groups have confirmed that these chemicals have significant antitumorous properties and selective toxicity against various types of cancer cells (without harming healthy cells) publishing eight clinical studies on their findings.”

These  acetogenins are selectively toxic for tumor cells “at very low dosages —as little as 1 part per million.”

Taylor explained that four studies published in 1998 specified the chemicals and acetogenins in soursop / graviola have the strongest anti-cancerous, anti-tumor and anti-viral capabilities.

She also said: “Mode of action studies in three separate laboratories have recently determined that these acetogenins are superb inhibitors of enzyme processes that are only found in the membranes of cancerous tumor cells.”

This explains why the acetogenins are toxic for cancer cells, but they are not toxic for healthy cells.

If you are familiar with soursop research then you may have heard about a laboratory research study conducted at Purdue University, in West Lafayette, Indiana.

A lot of this research was funded by The National Cancer Institute and the National Institute of Health (NIH).

Purdue University and its researchers have filed at least nine U.S. and/or international patents on their work around the anti-tumor and insecticidal properties and the related uses of the acetogenins they studied.

Purdue University revealed that (see this 1997 Purdue announcement) several of the Annonaceous acetogenins were “…not only are effective in killing tumors that have proven resistant to anti-cancer agents, but also seem to have a special affinity for such resistant cells.”

How cancer cells become drug resistant

Here is how that works: Cancer cells that are not killed by chemotherapy drugs can become resistant to the the anti-cancer agent. This process is called multi-drug resistanceCancer cells can create a pump within their walls that pushes anti-cancer drugs out of the cell. They stops them from being killed by these agents.

Only a small percentage of cancer cells in any given individual (approximately 2%)  may develop this defence mechanism. But they can replicate and become multi-drug-resistant tumors.

Research on acetogenins reported that the compounds were able to disable these intercellular pumps. This killed multi-drug-resistant tumors.

How soursop anti-cancer compounds work

The researchers at Purdue researchers said that the acetogenins block the transfer of ATP, which is where a cell gets its energy from. Starve them of an energy source and cancer cells will not grow or reproduce. They cannot run their pumps and defend themselves. Sothe result is that they eventually die.

Normal cells rarely develop this kind of internal pump. They don’t require a lot of energy as a consequence. Therefore they are not impacted by ATP inhibitor compounds. Purdue scientists said that 14 different acetogenins show effective ATP-blocking properties (several of these are found only in soursop).

The scientists also revealed that 13 of the 14 acetogenins tested were more potent against MDR breast cancer cells than all three of the standard drugs (adriamycin, vincristine, and vinblastine) used as controls.

Will extracts from soursop follow the same drug development path as Taxol?

Taylor suggests that research into sourop seems to be following the same path as Taxol, a well known cancer drug. Researchers discovered an anti-tumor capabilities of the bark from the Pacific Yew tree. From that work, Taxol was developed. This process, Taylor wrote, “took 30 years of research by numerous pharmaceutical companies, universities, and government agencies before the first FDA-approved Taxol drug was sold to a cancer patient.”

With graviola, it has taken researchers almost 10 years to successfully synthesize (chemically reproduce) the main antitumorous chemical, annonacin. These acetogenin chemicals have a unique waxy center and other unique molecular energy properties which thwarted earlier attempts, and at least one major pharmaceutical company gave up in the process (despite knowing how active the natural chemical was against tumors). Now that scientists have the ability to recreate this chemical and several other active acetogenins in the laboratory, the next step is to change the chemical just enough (without losing any of the antitumorous actions in the process) to become a novel chemical which can be patented and turned into a new patented cancer drug. (Naturally-occurring plant chemicals cannot be patented.) Thus far, scientists seem to be thwarted again—every time they change the chemical enough to be patentable, they lose much of the antitumorous actions. Like the development of taxol, it may well take government agenies like the National Cancer Institute and the National Institute of Health to step forward and launch full-scale human cancer research on the synthesized unpatentable natural plant chemical (which will allow any pharmaceutical company to develop a cancer drug utilizing the research as happened with taxol) to be able to make this promising therapy available to cancer patients in a timely fashion.

In the meantime, many cancer patients and health practitioners are not waiting… they are adding the natural leaf and stem of graviola (with over 40 documented naturally-occurring acetogenins including annonacin) as a complementary therapy to their cancer protocols. After all, graviola has a long history of safe use as a herbal remedy for other conditions for many years, and research indicates that the antitumorous acetogenins are selectively toxic to just cancer cells and not healthy cells—and in miniscule amounts. While research confirms that these antitumorous acetogenins also occur in high amounts in the fruit seeds and roots of graviola, different alkaloid chemicals in the seeds and roots have shown some preliminary in vitro neurotoxic effects. Researchers have suggested that these alkaloids might be linked to atypical Parkinson’s disease in countries where the seeds are employed as a common herbal parasite remedy. Therefore, using the seeds and root of graviola is not recommended at this time.

The therapuetic dosage of graviola leaf, (which offers just as high of an amount of acetogenins as the root and almost as much as the seed) is reported to be 2-3 grams taken 3 or 4 times daily. Graviola products (capsules and tinctures) are becoming more widely available in the U.S. market, and now offered under several different manufacturer’s labels in health food stores. As one of graviola’s mechanisms of action is to deplete ATP energy to cancer cells, combining it with other supplements and natural products which increase or enhance cellular ATP may reduce the effect of graviola. The main supplement which increases ATP is a common antioxidant called Coenzyme Q10 and for this reason, it should be avoided when taking graviola.

Graviola is certainly a promising natural remedy and one that again emphasizes the importance of preserving our remaining rainforest ecosystems. Perhaps—if enough people believe that the possible cure for cancer truly is locked away in a rainforest plant—we will take the steps needed to protect our remaining rainforests from destruction. One researcher studying graviola summarized this idea eloquently: “At the time of preparation of this current review, over 350 Annonaceous acetogenins have been isolated from 37 species. Our preliminary efforts show that about 50%, of over 80 Annonaceous species screened, are significantly bioactive and are worthy of fractionation; thus, this class of compounds can be expected to continue to grow at an exponential rate in the future, provided that financial support for such research efforts can be found. With the demise of the world’s tropical rain forests, such work is compelling before the great chemical diversity, contained within these endangered species, is lost.”

Posted in cancer.