AIDS Drug from Sunflowers?
Wednesday, February 15, 2006
filed under: Research and Development
Sunflower can produce a substance which prevents the AIDS pathogen HIV from reproducing, at least in cell cultures. This is the result of research carried out by scientists at the University of Bonn (www.uni-bonn.de/index_en.shtml) in cooperation with the Caesar Research Centre, both in Bonn, Germany.
Almost 40 million people are estimated to be living with HIV/AIDS worldwide, and it is now the leading cause of death worldwide among 15 to 59 year olds (www.knowhivaids.org). In the last few years, hopes for a completely new group of AIDS drugs have been pinned to what is known as dicaffeoyl quinic acid, or DCQA for short – a highly prized prototype for a new group of AIDS drugs. However, the substance is only available in very small quantities and is thus extremely expensive.
By using the Bonn method related to sunflower, the new class of AIDS drug may be produced for a fraction of the cost. Claudio Cerboncini of the Caesar Foundation and Ralf Theisen University of Bonn are principal investigators in the research. The researchers have patented their method, and together with the Jülich Research Centre, also of Germany, they now want to attempt to manufacture the substance on a large scale, and are looking for industry partners for assistance.
The sunflower-AIDS drug connection began when Cerboncini was investigating anti-fungal properties that the sunflower plant uses to fight off Sclerotinia sclerotiorum – this is the same type of Sclerotinia that has been problematic for sunflower produced in North America and around the world.
Cerboncini infected different types of sunflower with S. sclerotiorum. In this way he was able to isolate the antitoxins which the plants produce in response to the fungus, to help fight off infection. Among these is a substance which is also mentioned in research literature, albeit in a completely different context: DCQA, also proven to prevent the HI virus from reproducing, at least in cell cultures.
In contrast to other drugs, medical experts expect there to be only a few side-effects from DCQA. Initial clinical tests seem to confirm DCQA's potential. “We need these substances to expand our arsenal of effective weapons against the disease,” says Dr. Esther Vogt of the Immunological Out-Patient Service, Bonn University Clinic. “It remains to be seen, however, whether they will prove to be as effective in clinical practice as they seem to be at present.”
DCQA occurs in the artichoke and wild chicory, though in extremely small doses, at an extraction rate that would be expensive. But sunflower may prove to be an economical means of making the drug. Theisen explains that research can identify which genes the sunflowers activate when they produce DCQA in reaction to a fungus infection. This knowledge would make mass production of DCQA a distinct possibility.
“We want to attempt to cultivate sunflower cells or other plant cells in a nutrient solution together with Sclerotinia sclerotiorum, and then obtain the enzyme from the liquid,” Theisen says. “If things go according to plan, we could produce DCQA at a substantially reduced cost.” The process might be carried out on an industrial basis by using fermentation technology available at the Jülich Research Centre.
Potential impact in the U.S.
Brady Vick is a research chemist and research leader of the Sunflower Research Unit, Northern Crop Science Lab, USDA Agricultural Research Service, Fargo, N.D. It is the primary effort in the U.S. that is researching Sclerotinia in sunflower.
Vick says the German researchers from the University of Bonn are scientists with whom USDA-ARS Sunflower Research Unit scientists have interacted at professional meetings in Europe.
“We regard them as reputable scientists who are carrying on a long tradition of German science in the identification of natural products with activity against disease pathogens,” he says. “This is a good example of how funding of basic research, in this case plant-fungal interactions, can take a completely unanticipated path and lead to a startling new discovery that could potentially benefit millions of people afflicted with a deadly disease.”
Vick says it is possible that the groundbreaking German research could have implications for sunflower research in the U.S. For example, recent research by the USDA-ARS Sunflower Research Unit on sunflower resistance to S. sclerotiorum fungus shows that many wild perennial sunflowers native to the U.S. have demonstrated resistance to the disease. It is possible that similar research might be conducted with tissue cultures of wild sunflowers, to demonstrate antiviral activity against the HIV virus.
Sclerotinia is a devastating disease for many broad leaf crops around the world. Sunflower is infected in two ways…via the roots resulting in stalk rot and via spores which can infect the head. This plant disease may likely become more of a concern in the future as many farmers are forced to limit their rotations with small grains such as wheat and barley. There is a concentrated effort to fight this plant disease through a consortium of crops in what has come to know as the Sclerotinia Initiative. Vick reports that good progress has been made since this new funding has been made available. There are sunflower hybrids showing very good tolerance to disease and the USDA Sunflower Unit has released some resistant inbred lines for the private breeders. But, a possible cooperative or multi-pronged effort to fight both a devastating human and plant disease could be very positive.
– Tracy Sayler, with information from the University of Bonn