Fighting malaria with seaweed

Some hope in the search for new antimalarial drugs has come from a surprising source — a rare seaweed found only on South Pacific coral reefs.

In a hunt for novel compounds that might be harvested to fight human disease, a research team has for some years been examining life on Fijian coral reefs. They thought that organisms such as sponges and seaweeds might produce defensive chemicals to protect themselves against marine pathogens when injured by shallow-water agitation.

The team began examining substances found at abrasion sites on these organisms, and the star species turned out to be the Fijian red alga, Callophycus serratus. The team discovered that this clumpy seaweed has a sophisticated defence system that uses a range of compounds for protection against a single species of fungus.

According to a paper given at the annual meeting of the American Association for the Advancement of Science last month, a number of these compounds — all members of a group called bromophycolides — have tested positive in the laboratory against the malaria parasite (Plasmodium spp). The next step will be to test the lead compounds in a mouse model.

The discovery is part of a long-term collaboration between the Georgia Institute of Technology — a leading US research university — and the University of the South Pacific. Georgia Tech researchers are already working on laboratory synthesis of bromophycolides. This will allow structure modifications to improve activity or reduce side effects.

Ultimately, if an effective drug for human use is found, it may be possible to grow the drug in large amounts using a genetically modified micro-organism, such as a yeast.

And malaria is not the only disease for which the red weed offers hope. The researchers have previously reported on tests suggesting that the alga’s chemical defenders may also have action against cancer cells, HIV and staphylococcal bacteria.