Papaya Leaf Discovered to Stop Cancer Growth

papaya leaf cancer enzymes

Photo by Carolyn Conner

By Case Adams, Naturopath

Researchers have found that extracts from papaya leaf inhibit cancer cells and the growth of cancer. Researchers from University of Tokyo’s Institute of Medical Science studied leaf extracts from the plant Carica papaya Linn – the papaya tree.

The researchers tested extracts of different strengths against several human tumor cell lines and human peripheral blood mononuclear cells (PBMC). They found that the extract inhibited the growth of tumor cells, and increased the production of cytokines such as IL-2 and IL-4 among the PBMC cells.

The cytokines were then analyzed in vitro by ELISA, microarray and real-time RT-PCR testing.

Leading the research study was Nam Dang, M.D., Ph.D., a professor of medicine at University of Florida. He is a Harvard Medical School graduate and leading cancer researcher. The research also documented anecdotal experiences with patients with advanced cancers who achieved remission after drinking teas or tea extracts made from papaya leaves.

The research was published in the Journal of Ethnopharmacology. The article explains that papaya leaf boosts activity and production of the signaling molecules called Th1-type cytokines. These regulate the immune system, meaning that papaya leaves could have many other immunotherapeutic benefits.

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The researchers concluded:

“Since Carica papaya leaf extract can mediate a Th1 type shift in human immune system, our results suggest that the CP leaf extract may potentially provide the means for the treatment and prevention of selected human diseases such as cancer, various allergic disorders, and may also serve as immunoadjuvant for vaccine therapy.”

Papaya fruits also contain many of the constituents, such as papain, that are present in the leaves. Papayas, and more specifically green papayas, have also been used in traditional Polynesian medicine for many centuries to heal various disorders. The fruit contains linalool, benzylisothiaocyanates, chitinase and alkaloids such as carpaine and benzyl-glucosides. The leaves contain carpain, pseudocarpain, choline, carposide, choline, and dehydrocarpaine among others.

Chitinase from papayas has been found to have antibacterial activity, and carpaine and carpasemine (a benzylisothiocyanate) have been shown to have antihelmintic (inhibits parasites) properties. The fruits have long been used in traditional medicine for digestive ailments, ringworm, skin issues and urinary tract issues.


Otsuki N, Dang NH, Kumagai E, Kondo A, Iwata S, Morimoto C. Aqueous extract of Carica papaya leaves exhibits anti-tumor activity and immunomodulatory effects. J Ethnopharmacol. 2010 Feb 17;127(3):760-7.


Case Adams is a California Naturopath with a PhD in Natural Health Sciences, and Board Certified Alternative Medicine Practitioner. He has authored 26 books on natural healing strategies. “My journey into writing about alternative medicine began about 9:30 one evening after I finished with a patient at the clinic I practiced at over a decade ago. I had just spent the last two hours explaining how diet, sleep and other lifestyle choices create health problems and how changes in these, along with certain herbal medicines and other natural strategies can radically yet safely turn ones health around. As I drove home that night, I realized I needed to get this knowledge out to more people. So I began writing about health with a mission to reach those who desperately need this information. The strategies in my books and articles are backed by scientific evidence along with wisdom handed down through traditional medicines for thousands of years.” Case connects with the elements by surfing, hiking and being a beach bum.

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