Lethal 'antibiotic Class' Found Effective Against Malaria Parasite

by Hannah Punitha on Nov 6 2008 3:40 PM

A new class of antimicrobial agent with broad-spectrum activity has been found effective against Plasmodium falciparum, the parasite that is responsible for the most lethal form of human malaria, a new study has found.

The researchers have found that small molecule defensin-mimetic compounds discovered by Radnor, Penn.-based biopharmaceutical company PolyMedi could irreversibly kill P.falciparum responsible for lethal form of human malaria, sparing human red blood cells.

Lead researcher Doron Greenbaum, from University of Pennsylvania showed that these compounds kill P.falciparum irreversibly, meaning the cells do not recover when the agent is depleted.

Irreversible killing distinguishes a "cidal," or true killing mechanism, from a "static" mechanism that holds the infectious agent at bay while the body's immune system fights off the infection.

"If we treat for ten hours and remove the compound, the parasites never recover," said Greenbaum.

PolyMedix antibiotics are small-molecule non-peptide analogs of natural host defence peptides that higher animals use to fight infections. In humans these molecules are known as defensins.

They are believed to work by inserting themselves inside the lipid bilayers of cells that are deficient in cholesterol, thereby causing the cells to rupture and die.

Therefore these molecules kill pathogens by targeting membranes rather than proteins.

The study was presented at 48th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC).