The spray of topic is luminol – a chemical compound that glows in the dark when it comes into contact with an oxidizing agent. One such oxidizing agent is hemoglobin – a protein molecule in red blood cells that carries oxygen throughout the body.
In their study, first author Paul Sigala and colleagues, from Washington University in St. Louis, reveal how luminol triggers an amino acid present in hemoglobin to kill the malaria parasite Plasmodium falciparum in red blood cells.
When P. falciparum infects a human red blood cell, it takes hold of the non-protein, oxygen-carrying part of hemoglobin – known as heme – for survival. However, it was unclear exactly how the malaria parasite captures heme.
The researchers infected human red blood cells with P. falciparum and observed an “unnatural channel” that appeared on the cells’ surface.
On introducing an amino acid present in heme to a solution containing the red blood cells, the team found the amino acid entered the cells through the newly-created channel and began making heme. This process, say the authors, led to an accumulation of a molecule called protoporphyrin IX.
Researchers say luminol – a compound used at crime scenes to identify blood traces – may also be an effective tool in the fight against malaria.
Luminol and the antimalarial drug artemisinin were introduced to the malaria-infected blood cells. The team found protoporphyrin IX reacted to the light and produced free radicals that killed the P. falciparum parasites.
“The light that luminol emits is enhanced by the antimalarial drug artemisinin,” explains senior author Dr. Daniel Goldberg. “We think these agents could be combined to form an innovative treatment for malaria.”
New approach may offer more effective treatment for malaria
According to the World Health Organization (WHO), there were around 198 million cases of malaria in 2013 and around 584,000 deaths from the disease – around 90% of which occurred in Africa among young children.
At present, artemisinin is considered the first-line treatment for malaria, though WHO recommend it only be used in conjunction with other treatments because P. falciparum is developing resistance to the drug.
Sigala and colleagues believe their research may represent a more effective treatment strategy for malaria, primarily because their approach targets proteins produced by red blood cells, which P. falciparum is unable to mutate as a way of developing drug resistance.
Next, the team will test their novel approach in animal studies, and they are confident such studies will yield encouraging results. Dr. Goldberg says:
“All of these agents – the amino acid, the luminol and artemisinin – have been cleared for use in humans individually, so we are optimistic that they won’t present any safety problems together. This could be a promising new treatment for a devastating disease.”
Last month, Medical News Today reported that European drugs regulators have given their approval for the world’s first malaria vaccine, bringing us closer to prevention of the devastating disease.