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Healing papaya

Latex from fruit found in Chile contains healing substances for different kinds of skin wounds

MÍRIAM TERESA PAZ LOPES/ UFMGIn March of this year, researcher Carlos Edmundo Salas Bravo, from the Federal University of Minas Gerais (UFMG), had, in Chile, one more proof that he is on the right track in his research with the plant called Carica candamarcensis, a sort of papaya native to the west coast of South America. He accompanied the results of an ointment made from the latex of the small papaya that healed the burnt skin of a diabetic Chilean patient who had already tried, without success, all the conventional treatments. Chilean by birth, Salas began to research the healing properties of the plant at the end of the 1980’s. From then until now, he was joined by researcher Miriam Teresa Paz Lopes, also from UFMG, and Chilean pharmacist Abrahan Schnaiderman.

In 2002, the three researchers filed a patent registration request in the United States of the therapeutic properties of the substances found in the latex of the papaya. The active ingredients of the plant are in some proteases, a kind of protein that has the function of breaking up other proteins, with the objective of activating them or of deactivating them, favoring, in these cases, the mechanism of cell proliferation.

The product has already been tested on animals. Now, the researchers hope that some institution or pharmaceutical company will be interested in the patent and testing humans. he studies show that the substances found in the latex of the fruit of C. candamarcensis have a potential for curing different kinds of skin wounds and may be extremely effective in chronic one or those difficult to heal, like the ones common in victims of diabetes, bedsores (wounds that appear in patients who remain bedridden or in the same position for long periods) and those caused by burns.

Gastric lesions
The proteases were also tested on gastric lesions and proved to be more effective against ulcers than Omeprazole and Ranitidine, medicines used for treating this problem and gastritis. For skin wounds, the studies were carried on hairless mice, and for gastric wounds, the tests were done with rats. For the time being, tests on humans are isolated, carried out only in cases like that of the Chilean woman who authorized the use of the substance on her wounds.

The interest for the high content of proteases present in the latex of C. candamarcensis made Salas, with his doctorate in biochemistry from the Universities of Chile and Michigan, in the United States, to start his studies with the fruit in 1988. The presence of these substances in this papaya prevents it from being consumed in natura as our papaya (Carica papaya) is, making it indigestible unless it is cooked. In the continuation of his studies, in 1991, at the Faculty of Medicine of the University of São Paulo (USP), Salas met biophysician Miriam Lopes, a professor at the Experimental Oncology Laboratory who was dedicating herself to research in cell development, in particular in the proliferation of tumor cells. They ended up getting married and, in 1992, were transferred to UFMG, in Belo Horizonte, where they are professors of the Biological Sciences Institute (ICB).

With the development of the studies with proteases, the researchers went on to study the action of the latex from C. candamarcensis on wounds of animals, and they started their tests on mice. “We started to observe how the enzymes acted on the cells of mammals, because we had already observed the coagulation that occurs in the fruit when it is damaged”, Miriam says.

In the 50 or so mice with wounds on their skin, they observed that fractions of this latex would bring about healing and encourage the division of cells in the neighboring regions not affected by the wound, besides cleaning up the wounded tissue. The researchers had already found out in laboratory experiments that the substances present in the latex stimulate the proliferation of fibroblasts (the deepest tissue of the skin) and the epithelial cells (the closest to the surface), fundamental in the healing process.

Miriam explains that the process of healing a wound occurs when the affected tissue is replaced by another. It seems simple, but only people that suffer from chronic wounds or wounds that are difficult to heal know the sacrifice to which they are submitted. Healing substances normally work in cleaning up the wound, which favors the work of new cells being reproduced by the organism itself, which does not always manage to do this. “In the case of healing with the protease from C. candamarcensis, the process is quicker than the conventional one, but the most important thing is the good quality of the reconstruction of the wounded tissue”, she says.

Toxicological study
The research was done almost without any financial support from the scientific research agencies. “We have been taking this project forward at the speed we have been able to. In the initial stage, between 1994 and 1996, we were funded from the National Council for Scientific and Technological Development (CNPq). A major part of the project was carried out with existing funds at UFMG’s laboratories”, Miriam explains. Besides Schnaiderman, the Chilean partner, there is another one, working in Spain. Researcher Arturo Anadón, from the Complutense University of Madrid, is carrying out toxicological studies on animals.

The expectation for producing the medicine runs into the difficulty of cultivating the plant, which is not typical of the Brazilian climate. “The solution may lie in finding a microclimate suitable for cultivating C. candamarcensis or in producing the substance in the laboratory, by means of cloning and expressing the protease in bacteria”, Miriam explains. The researchers now have the expectation of carrying on with their work, in particular carrying out clinical tests on humans. “We are open to negotiations, including with pharmaceutical laboratories, because a medicine with this potential will certainly meet with an excellent acceptance on the market”, Salas concludes.