Acriflavine, an antiseptic in widespread use early last century, but abandoned with the discovery of Penicillin, could help tackle the rise of antibiotic-resistant bacteria, often known as superbugs. Even more remarkably, Acriflavine appears to boost the body's immune response to viruses, providing a defense against the common cold, and possibly more serious viral diseases.

The great German scientist Paul Ehrlich discovered in 1912 that Acriflavinium chloride, known as acriflavine, could treat certain diseases when applied to the skin. It was used to treat sleeping sickness in sub-Saharan Africa, to prevent wounds becoming infected during World War I and even intravenously against gonorrhea.

Dr Michael Gantier of Australia's Hudson Institute of Medical Research thinks there is life in the chemical yet, providing an alternative method for controlling bacteria that have developed resistance to widely used antibiotics. Gantier is senior author of a paper in Nucleic Acids Research presenting evidence that very small doses of Acriflavine produce an immune response in cultured cells, enhancing their capacity to fight off pathogens.

“We have shown for the first time that Acriflavine binding to cellular DNA could activate the host immune system, unleashing a powerful immune response on a potentially broad range of bacteria,” Gantier said in a statement. 

First author Dr Genevieve Pepin, also of the Hudson Instittute, added: “Our study indicates that Acriflavine stimulates the host immune system, rather than simply killing bacteria, suggesting it wouldn’t be as likely to drive mutations in bacteria – showing a safeguard against resistance and a potential alternative to current antibacterial drugs.”

More surprisingly, the immunity boost, at least in cultures, extends to fighting viruses. Gantier and his co-authors propose herpes as an example of a virus against which Acriflavine could prove useful, since it could be applied at the site of an outbreak, just as it was for external wounds.

Acriflavine is poisonous if consumed or inhaled, but Gantier told IFLScience the immunity boosting appears to take place at doses far lower than those that do damage. Consequently, he suggests, it should be possible to use an intranasal inhaler to deliver a small dose to the cells of the nose and lungs, to fend off upper respiratory tract infections. This could protect against cold viruses in an ordinary season, and prove a life saver if given to those most at risk during an outbreak of something like SARS. 

Gantier told IFLScience Acriflavine appears to have been abandoned for intravenous use “because it was very short lived in the blood stream.” However, it is much more long-lasting when applied to the skin, and Gantier suspects the same will prove true for the respiratory tract, although clinical trials have yet to be conducted.

Acriflavine's revival can in part be attributed to the Internet, with German scientific papers from the early 20th century now being easily available to researchers worldwide, providing very useful pointers for research.

[H/T: ABC.net.au]