Queensland researchers say a native Australian plant which "grows all over the place" may hold the key to developing a potential treatment for dengue virus.
There is no cure or vaccine for the mosquito-borne virus which infects 390 million people a year.
Scientists from the Queensland University of Technology (QUT) have conducted tests on monkey cells and found the plant, identified only as Species 8473 for commercial reasons, killed all four strains of the dengue virus.
Dr Trudi Collet said the results were promising.
"We tested it against all four strains of the dengue virus and found that we can 100 per cent kill all four strains without any damage to the host mammalian cells," she said.
"So it's pretty incredible. We're very, very excited about this finding."
Dr Collet said her research team had previously found the same plant contained compounds that could kill the Zika virus.
In the latest research, Dr Collet's team infected monkey cells with the dengue virus and about a week later added extracts of the plant.
"We've taken leaves from this particular plant, we've dried them down, ground them into a fine powder, and then we've basically extracted as many compounds as we can using either water or other chemicals," she said.
"It was effective even after two hours of putting onto the infected cells, so it was actually quite quick."
Dr Collet said it should take another eight to 12 weeks to identify the compound responsible.
She said she hoped to eventually synthesise the compound to not only treat people who were infected, but for a preventative or prophylactic drug.
"So if you're travelling overseas to a country where the virus is rife, you could take the medicine beforehand to protect yourself from contracting the virus," she said.
But she said it could be years before a drug derived from the plant was deemed safe for humans and available on the market.
"You're looking at anywhere from eight to 15 years to be quite honest," she said.
"That process however can be expedited if there is enough funding to help push that through, so that's what we're hoping for."
Long and complex road to medication
Dr Collet started investigating the plant's effectiveness against mosquito-borne viruses at a time when Zika virus was "absolutely rampant".
"I already knew that the plant in question... had anti-bacterial effects against a whole range of different bacteria," she said.
"The premise is out there already for plants that are not only antibacterial but antiviral.
"Looking at the results was just — I can't even begin to describe how excited I was."
The acting director of Queensland Health's Tropical Public Health Services in Cairns, Roscoe Taylor, said dengue fever was a serious disease for which there was currently no specific treatment.
"It is positive to see research into potential remedies for use in the future," he said.
"However, it is also important to note that the pathway from identifying a potentially effective compound and turning it into an effective and safe medicine registerable with the Therapeutic Goods Administration is usually long and complex as well as costly."
The QUT team will also investigate the plant's effectiveness against Hepatitis C, which is in the same family of Flaviviridae viruses.
The research, as well as the identity of the plant, will be published once the effective compounds are identified and patented.
