A group of compounds commonly found in garlic may not only be an effective treatment for malaria – the mechanism by which they inhibit the infection appears to be similar to the mechanism they use to fight cancer cells.
Researchers from the University of Toronto reported these findings in early November 2001 at the 50th Annual Meeting of the American Society of Tropical Medicine and Hygiene in Atlanta.
“Does eating garlic influence the outcome of malaria? There is evidence that yes, it may,” says Ian Crandall, Assistant Professor of Laboratory Medicine and Pathobiology at the University of Toronto, who presented the study.
The compounds, called disulfides, occur naturally in garlic, onions and mahogany trees and are known to have antifungal, anticancer and antibacterial properties.
For years scientists have suspected that one of these compounds in garlic may be helpful against malaria and have proven it in animal models.
Crandall and his colleagues, though, were more interested in understanding how these disulfides worked against infection.
They tested 11 different synthetic disulfide compounds against malaria-infected cells. They also tested the effect of these compounds on cancer cells. While not all of the disulfides were effective against Plasmodium falciparum, the malaria parasite, those that were also effective at killing the cancer cells.
“We looked at the active compounds to see what they had in common. Apparently P. falciparum-infected cells and these cancer cells seem to have the same susceptibility profile,” says Crandall.
Crandall believes that the mechanism of action may be on the glutathione system within the cell. In this system, the glutathione is reduced (the opposite of oxidation) and stored in the cell like energy in a battery. This reduced glutathione can then be brought out to absorb damage caused by oxygen and other harmful particles when needed.
The glutathione system is of particular importance in cells that rapidly reproduce, like cancer cells or malaria-infected cells, because these harmful particles are natural by-products of metabolism.
Ajoene, the disulfide that naturally occurs in garlic, is a known inhibitor of glutathione reduction. “Normal cells recharge glutathione and therefore are able to deal with the oxidative stress that normal metabolism generates, but in the presence of an inhibitor they cannot recharge and therefore are more prone damage and eventually death,” says Crandall.
Crandall hopes that one days these compounds may be used to treat not only malaria, but some types of cancer as well. There is one drawback, though. “Does this stuff smell like garlic? Well, every time we open a vial of it in the lab everybody runs.”