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Pharmacology

Sugar, but no arthritis

A component of guar gum alleviates pain and prevents damage in the joints progressing

Miguel BoyayanSugar from guar gum magnified 500 timesMiguel Boyayan

When you eat guar gum it staves off hunger. Because it is rich in fiber it is believed that it helps control cholesterol, diabetes and obesity. It is a common thickener in industrialized foodstuffs, cosmetics and medication. But those are not the only properties of this substance that is obtained from the seeds of a plant, Cyamopsis tetragonolobus, which originates in India and Pakistan and that seems to have a 101 uses. In experiments with rats a team from the Federal University of Ceará (UFC) noticed that one of the components of guar gum, a sugar known as galactose, can reduce pain, halt cartilage loss in joints and at least partly reconstitute the movement lost with arthritis, a disease associated with aging that tends to deform and immobilize above all the hands, hips, knees and feet.

In 2002 Francisco Airton Castro da Rocha, a professor from the Department of Clinical Medicine, and Judith Pessoa de Andrade Feitosa, from the Organic and Inorganic Chemistry Department, began jointly investigating the possibilities for using guar gum as an anesthetic. Guar gum is a galactomanane, a complex sugar or polysaccharide formed by mannose and galactose, in the proportion two to one. When used in its natural state the researchers from the UFC discovered that guar gum causes inflammation in joints corroded by arthritis, one of the areas of Rocha’s work. They subsequently removed the protein and saw that the remaining sugars could alleviate the pain caused by arthritis. After a little more work they isolated the sugar responsible for this action, galactose, which is found in fruit and in large quantities in coffee. The experiments so far carried out suggest that guar gum could function both as a gel as well as in solution. “The most recent results have shown that galactose can protect against destruction of the cartilage that covers the bones”, says Rocha. “There’s still no medication that prevents the arthritis from progressing.”

Chemical characterization, the experiments for removing or adding components and the effectiveness tests in animals have taken the form of four scientific articles published in international scientific journals, two Masters and two PhD theses, a prize awarded by the Brazilian Society of Rheumatology in 2004 and a patent lodged the following year to guarantee the right to use the knowledge generated at the university.  And that is where problems that have not yet been overcome started to appear, beginning with the toxicity tests in laboratory animals, which if they are successful may allow for tests on human beings.

Rocha believes that guar gum, because it comprises sugars that continually circulate through the organism, is not toxic and neither will it causes allergic reactions. But he will have to prove this, through a series of rigidly standardized pieces of work in order to comply with the arduous process for developing a new medication in accordance with international rules. “We have no way of doing that here in the university”, he says. “I thought about setting up a company [to do the preclinical testing], but I don’t have the expertise and this is not what I want to do in life.” Rocha says he has visited five companies, including a multinational, has shown them the gel and the scientific articles but the conversation did not progress because all would like to see the results of tests on human beings, which can only be done after the animal tests.

Botanist Marcos Buckeridge, from the University of São Paulo (USP), experienced something similar. In 2001 he found galactomananes in abundance in the seeds of a tree that is typical of the Cerrado [scrubland], the faveira (Dimorphandra mollis). As these sugars were chemically identical to those of guar gum he imagined that faveira seeds might be an alternative source of guar gum. He then created the simplest possible process for extracting galactomananes, but instead of patenting it he published the results in a scientific article in the Brazilian Journal of Food Technology. “I intended to encourage the sustainable use of the seeds and to help with conservation of the Cerrado”, says Buckeridge. “In order to exploit the seeds the trees would have to be preserved.”

In 2004 Buckeridge and his team identified another sugar, betaglucane, in the leaves of Natal (Rynchelytrum repens), which in preliminary experiments in mice reduced the level of glucose in the blood by half; it could therefore be an alternative method for treating diabetes. So far he has not managed to advance with this research, but immediately after he discovered another sugar, this time a xyloglucane, in the gum taken from a seed of the jatoba (Hymenaea coubaril), which could be used in skin creams. Instead of torturing himself doing experiments on animals and leaving the discovery to become a burden he went down another route: he requested a patent and passed it on to a cosmetics company in exchange for equipment for the laboratory he was setting up at USP.

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