Frog slime may provide a new way to prevent flu epidemics, research suggests.
Frogs have received a lot of attention, because it is easy to isolate peptides from the slimy layer of mucus on their skin.
In another part to the study, the scientists tested the action of urumin in vivo by testing the extent to which peptide treatment could protect mice infected with the flu.
"The frogs secrete this peptide nearly certainly to combat some pathogen in [their] niche", lead researcher Joshy Jacob told Gizmodo. "In the beginning, I thought that when you do drug discovery, you have to go through thousands of drug candidates, even a million, before you get 1 or 2 hits".
The frog mucus research is the first evidence of the slime's flu-killing ability. "And here we did 32 peptides, and we had 4 hits". They discovered that four of them were able to act against the virus. Well, at least one type of frog.
One of the molecules, urumin, successfully killed several viral strains, as well as a number of harmful microbes.
When researchers squeezed some urumin into the noses of lab mice, the peptide protected them against what would have otherwise been a lethal dose of H1 flu virus, the kind responsible for the 2009 swine flu pandemic. However, it was not effective against other current flu strains such as H3N2, the investigators found.
Developing antimicrobial peptides into effective drugs has been a challenge in the past, partly because enzymes in the body can break them down.
Dr Jacob's team is now looking at ways to stabilise anti-viral peptides such as urumin. Additionally, other studies with amphibians have highlighted the potential of their host-defence peptides against a range of different viruses, in-vitro.
Such drugs could prove important when vaccines aren't available to deal with new strains of pandemic flu, or when known flu strains develop resistance to current medications, said study senior author Joshy Jacob. It binds the stalk of hemagglutinin, a less variable region of the flu virus that is also the target of proposed universal vaccines. "And then it kills the virus".