Scientists at the Georgia Institute of Technology say that a type of tropical seaweed may hold the key to producing the next generation of treatments for malaria.
A group of chemical compounds used by a species of tropical seaweed to ward off fungus attacks may have promising anti-malarial properties for humans.
The compounds are part of a unique chemical signaling system that seaweeds use to battle enemies – and that may provide a wealth of potential new pharmaceutical compounds.
Using a novel analytical process, researchers found that the complex antifungal molecules are not distributed evenly across the seaweed surfaces, but instead appear to be concentrated at specific locations – possibly where an injury increases the risk of fungal infection.
The class of compounds is known as bromophycolides.
“These molecules are promising leads for the treatment of malaria, and they operate through an interesting mechanism that we are studying,” said Julia Kubanek, an associate professor in Georgia Tech”s School of Biology and School of Chemistry and Biochemistry.
“There are only a couple of drugs left that are effective against malaria in all areas of the world, so we are hopeful that these molecules will continue to show promise as we develop them further as pharmaceutical leads.”
The new findings have been reported at the annual meeting of the American Association for the Advancement of Science (AAAS) in Washington, D.C.
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Researchers are turning to traditional medicines to fight against malaria.
As of now, patients are treated with Artemisinin combination therapy but resistance of the parasite to this treatment is increasing.
In the face of this resistance, researchers are looking at natural compounds to provide a starting point for the development of new drugs.
Traditional remedies are widely used especially in areas of poverty or where there is no access to medical treatment.
The combination of artemisinin, flavanoids, and other compounds, which occur naturally in the leaves of Artemisia annua, increases the effectiveness of the treatment and decreases metabolism of the active ingredient.
Circumin (from turmeric) has anti-malarial properties and is being tested for use against cerebral malaria. Adding piperine (from black pepper seeds) to circumin increases the effectiveness of circumin 2000 times.
Plant extracts such as lemon eucalyptus, citronella, and neem oil also have use as insect repellents but are not as yet recommended for use by the Environmental Protection Agency.
Researchers suggest following the Research Initiative on Traditional Anti-Malarial Methods (RITAM), which shows a consensus of observational and laboratory results with clinical clearance of parasites.
They also advocate the inclusion of native healers for the review of disease surveillance, ethnobotanical treatments, and changes in health care policy to increase the validity of these traditional medicines.
The study would appear in Malaria Journal on World Malaria Day on the 25th April 2011.
A class of chemotherapy drugs designed to block signalling pathways in cancer cells also kills the parasite that causes malaria, opening up a whole new way of combating this deadly disease.
The research shows that the malaria parasite depends upon a signalling pathway present in the host, initially in liver cells, and then in red blood cells (RBCs), in order to proliferate.
The enzymes active in the signalling pathway are not encoded by the parasite, but rather hijacked by the parasite to serve its own purposes.
These same pathways are targeted by a new class of molecules developed for cancer chemotherapy known as kinase inhibitors, the journal Cellular Microbiology reports.
When a team from the Global Health Institute (GHI) and Inserm, the French agency for biomedical research, subjected RBCs infected with malaria to the chemotherapy drug, the parasite was stopped in its tracks, according to a GHI statement.
Christian Doerig and his colleagues tested RBCs infected with plasmodium falciparum parasites and showed that the specific PAK-MEK signalling pathway was more highly activated in infected cells than in un-infected cells.
When they disabled the pathway, the parasite was unable to proliferate and died. Applied in lab, the chemotherapy drug also killed a rodent version of malaria (P. berghei), in both liver cells and red blood cells.
This indicates that hijacking the host cell’s signalling pathway is a generalized strategy used by malaria, and thus disabling that pathway would likely be an effective strategy in combating the many strains of the parasite known to infect humans.
Malaria infects 250 million and kills one to three million people every year worldwide.
A new study has suggested that a genetically engineered fungus carrying genes for a human anti-malarial antibody or a scorpion anti-malarial toxin could be a highly effective, specific and environmentally friendly tool for combating malaria.
University of Maryland-led team of scientists said that this general approach could be used for controlling other devastating insect and tick bug-borne diseases, such as or dengue fever and Lyme disease.
“Though applied here to combat malaria, our transgenic fungal approach is a very flexible one that allows design and delivery of gene products targeted to almost any disease-carrying arthropod,” said Raymond St. Leger, a professor of Entomology at the University of Maryland.
“In this current study we show that spraying malaria-transmitting mosquitoes with a fungus genetically altered to produce molecules that target malaria-causing sporozoites could reduce disease transmission to humans by at least five-fold compared to using an un-engineered fungus,” said Leger.
The researchers created their transgenic anti-malarial fungus, by starting with Metarhizium anisopliae, a fungus that naturally attacks mosquitoes, and then inserting into it genes for a human antibody or a scorpion toxin. Both the antibody and the toxin specifically target the malaria-causing parasite P. falciparum.
The team then compared three groups of mosquitoes all heavily infected with the malaria parasite. In the first group were mosquitoes sprayed with the transgenic fungus, in the second were those sprayed with an unaltered or natural strain of the fungus, and in the third group were mosquitoes not sprayed with any fungus.
The research team found that compared to the other treatments, spraying mosquitoes with the transgenic fungus significantly reduced parasite development. The malaria-causing parasite P. falciparum was found in the salivary glands of just 25 percent of the mosquitoes sprayed with the transgenic fungi, compared to 87 percent of those sprayed with the wild-type strain of the fungus and to 94 percent of those that were not sprayed.
Even in the 25 percent of mosquitoes that still had parasites after being sprayed with the transgenic fungi, parasite numbers were reduced by over 95 percent compared to the mosquitoes sprayed with the wild-type fungus.
The study has been published in the journal Science.