Papaya leaf and cancer
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 common 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. Dr. Dang 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 journal of the International Society 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.
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.
Key constituents of papaya
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.
Other research shows that fermented papaya stimulates the immune system.
REFERENCE:
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.