Seaweed’s Tricks May Lead To More Effective Malaria Drugs In Future
An antifungal compound produced by a species of tropical seaweed also attacks the malaria parasite, Plasmodium falciparum, scientists reported on Monday at the annual meeting of the American Association for the Advancement of Science (AAAS). If researchers can replicate their findings in animal and human tests, the compound could lead to the development of more effective malaria drugs in the future.
In 2009, there were an estimated 225 million cases of malaria worldwide, and 781,000 deaths caused by the disease, according to the World Health Organization’s 2010 Malaria Report – the most recent data available. Even though these statistics represent a drop in the numbers of malaria cases and deaths from previous years, health experts worry about the emergence and spread of strains of malaria that are resistant to artemisinin – the most effective antimalarial to date – could reverse these gains if new agents are not discovered soon.
Julia Kubanek, of the Georgia Institute of Technology, was leading a team of researchers interested in how marine plants and animals protect themselves from infection, when they came across the seaweed Callophycus serratus, which lives on tropical coral reefs in waters off Fiji. The red algae produced a class of compounds known as bromophycolides, which protected it from the growth of Lindra thalassiae, a common marine fungus. Biomedical screening revealed bromophycolides had antimalarial properties.
Science Now describes the mechanism Kubanek’s group believes bromophycolides are using to kill off the malaria parasite: “Malarial parasites infect red blood cells and they thrive on hemoglobin, the body’s oxygen-carrying molecules,” but as they break hemoglobin down, “they release heme, a pigment that is toxic to them.” As Kubanek reported on Monday, early studies suggest bromophycolide interferes with the parasite’s natural response to heme, resulting in the poisoning of the parasite. It’s a strategy similar to that taken by the drug chloroquine – an early generation antimalarial that Falciparum has developed a resistant to in parts of the world where malaria is endemic.
“We are still working on this area, but so far we know that bromophycolides are toxic to Plasmodium falciparum, including at least one chloroquine-resistant strain, at sub-micromolar concentrations,” Kubanek said, according to Guardian. “That is not whopping potency – artemisinin is more effective. But it is promising as a lead molecule and we hope to eventually design a more potent and selective derivative.” The researchers now plan to test the effectiveness of the compound in mice infected with malaria.
The World Health Organization has been increasingly focused on the issue of antimicrobial resistance worldwide. In January, the agency launched a global initiative to stop the spread of artemisinin-resistant malaria by increasing surveillance, improving access to diagnostics and greater investment in artemisinin-related research. In April, the WHO plans to introduce several policy measures to fight the spread of antimicrobial resistance worldwide.
