Frog mucus might seem like a bizarre flu remedy a witch doctor would suggest, however in the future, more respected medical professionals could be prescribing it. Researchers at Emory University have found that certain peptides excreted by frogs can fight off human flu strains and they could be used in emergency situations of flu outbreaks when regular vaccines aren’t available.
Composed of short chains of amino acids, peptides are essentially mini-proteins and they perform a variety of functions in the body. Some peptides are antimicrobial, playing a role in animal’s immune system though they generally benefit the species that are producing them. Researchers wanted to see if these flu fighters could carry across to humans.
Different frogs make different peptides depending on their habitat. Researchers found out one frog that makes peptides that is effective against the H1 influenza type.
For this work, researchers collected 32 different peptides from a frog species called Hydrophylax Bahuvistara, that is native to southern India. Frogs are good resources since their peptides are easy to collect and isolate. Researchers give them a mild electric shock or rub powder on their back, and they secrete them in defense.
The team tested the peptides against human flu strains and 32 types were collected, of which 4 of them proved effective. That was a much higher number than the researchers were expecting.
Of the four, only one may be safe for human use. In lab tests, researchers exposed human RBCs to the different peptides, using electron microscopy found that 3 of them were toxic. The 4th which the team dubbed “Urumin” was lethal to the flu but harmless to us.
Urumin was effective against dozens of Flu strains. However, the exact mechanism is not clear, it appears that the peptide’s tactics involve binding to a protein called hemagglutinin on the surface of the virus. Putting the H in H1, this protein is a key part of how the flu virus gains grips and attacks healthy human cells.
The virus requires hemagglutinin to get inside our cells. This peptide does it binds to the hemagglutinin and destabilizes the virus and kills it.
When tested on mice, Urumin administered through the nose was found to protect the animals from lethal doses of some types of flu, like the H1N1 swine flu that struck in 2009, but had little effect against current strains like H3N2. While the peptides probably won’t make up for vaccines, they could be used as stop-gaps where vaccines aren’t yet available to help slow the spread of future pandemics.
Researchers are now developing ways to keep the peptides stable inside the body where natural enzymes would work to break them down and continuing to search for frog peptides might be effective against other viruses.