UC IRVINE RESEARCHERS CREATE NEW CHEMICALS THAT SHOW PROMISE IN FIGHTING AIDS
Chemicals Derived From Extracts of South American Coffee Beans, Exotic Flowers
Irvine, Calif., Feb. 11, 1999 -- Using extracts from plants prescribed by Bolivian shamans for more than 1,500 years, researchers at UC Irvine's College of Medicine have created a group of chemicals that appear to slow the infection of healthy cells by HIV, the virus that causes AIDS. The chemicals could be used to create a new type of medicine to treat AIDS if they ultimately prove to be effective in humans.
Dr. Edward Robinson, associate professor of pathology and microbiology at UCI, and his research team--working with Dr. Manfred Reinecke, professor of chemistry at Texas Christian University in Fort Worth--created seven chemicals that, in laboratory tests, proved to inhibit HIV as well as or more effectively than the actual plant extracts. The researchers' findings are reported in the Feb. 11 Journal of Medicinal Chemistry.
These chemicals, called analogues, are similar to the natural extracts that were derived from plants, but have been refined in the laboratory to provide more potency against disease. Many current drugs are analogues of organic materials, including aspirin, which originated from the bark of a willow tree.
The plants from which Robinson and his researchers made extracts range from rare flowers to chicory and green coffee beans. Once the extracted chemicals were identified, the researchers created the analogues and tested them for potency. The seven synthetic chemicals that were most effective included two variants of chicoric acid, which is chemically similar to an extract from chicory; four forms of tartaric acid, similar to a popular food preservative, and a chemical related to other Bolivian extracts called dicaffeoylglyceric acid.
Chemicals derived originally from plants account for nearly one-third of all medicines used today. The extracts studied by Robinson and his research colleagues are from a group of plants used by Kallawaya shamans in Bolivia for centuries to treat a variety of illnesses. The Kallawaya use approximately 900 plants as sources for medicines.
The current research on the AIDS-fighting value of these plants started several years ago when Robinson began working with Dr. Joseph Bastien, professor of anthropology at the University of Texas at Arlington, who had gathered about 60 of the Kallawaya plants. Reinecke made extracts of the plants and tested them for chemical activity against a variety of disorders, including cancer, infections and malaria. Robinson then worked to test how effectively Reinecke's plant extracts acted against AIDS.
"These analogues are important because they show that we can make a synthetic molecule that works better than natural substances at curbing HIV activity," Robinson said. "They are helping us to understand what are the key elements of a chemical that are effective against the AIDS virus."
Robinson and his research group have been looking at how the plant extracts slow the activity of an enzyme called HIV integrase, which helps cause AIDS by integrating the infectious virus into the DNA of healthy cells. Integrase then forces the healthy cell to create more HIV, which helps spread the virus to even more cells.
HIV integrase is one of three key enzymes that cause the AIDS virus to spread. The other two enzymes, HIV protease and HIV reverse transcriptase, have for years been the targets of anti-AIDS "cocktails," which are mixtures that arrest the course of the disease and have been prescribed routinely to AIDS patients for several years. The chemicals that fight HIV integrase, if proven effective, could become part of this anti-AIDS cocktail.
The researchers also have found that the chemicals that fight HIV integrase can do the job at doses that are not toxic to cells, a promising sign of their ability to combat AIDS. Currently, cocktails used against AIDS are toxic to healthy cells and have negative side effects.
The next step in Robinson's research is to make even more chemical derivatives to find out which work most effectively on HIV, a process Robinson estimates may take up to two years. He cautions that the process of testing for medicinal use in people will take even longer. "We'll need to go through several levels of testing on animals before we're confident enough to test any chemicals on humans," he said.
###
Contact: Andrew Porterfield
(949) 824-3969
[email protected]
A complete archive of press releases is available on the World Wide Web at http://www.communications.uci.edu/~inform/
RSS