A cure for the common cold is a step closer following a study into tiny molecules found in immune systems, according to scientists.

Researchers at Edinburgh Napier University say treatments based on "antimicrobial peptides" could be used to fight colds.

A five-year study into peptides from different mammals found they were all able to combat rhinovirus, the most frequent cause of the common cold.

It is hoped scientists will be able to use this information to develop drugs that treat colds as well as chronic lung conditions such as asthma.

Dr Peter Barlow, associate professor of immunology and infection at Edinburgh Napier, hailed the new research as "an exciting development".

He said: "There is no cure and no vaccine so the development of effective therapies for human rhinovirus, the main causal agent of the common cold and one of the most common causes of viral respiratory tract infections, is an urgent requirement.

"This study represents a major step towards finding a treatment."

Dr Barlow's research found certain peptides from pigs and sheep, as well as those in human immune systems, were "potent" at treating rhinovirus in humans.

The £200,000 study, published in the journal Peptides, was funded by the Chief Scientist Office and medical research charity Tenovus Scotland.

Using peptides "synthesised" in the laboratory, researchers Filipa Henderson Sousa and Dr Victor Casanova assessed the impact of the different peptides on lung cells infected with human rhinovirus.

The peptides successfully attacked the virus, and could provide clues for developing novel treatments based on peptides found in nature.

Dr Barlow said: "This is an exciting discovery and our next steps will be to modify the peptide to make it even better at killing this virus.

"This research is still in the early stages but we will ultimately be looking to develop drug treatments that have the potential to cure the common cold."