A type of seaweed may be more effective at fighting flu than conventional drugs, say scientists in Japan.
Could seaweed stop flu?
They believe the medicinal properties
of sargassum piluliferum, found in shallow sea waters around Japan, are so strong they may even help fight Aids.
The scientists, who are based at Saga University, said an extract taken from the seaweed had proved effective in laboratory tests.
They are now hoping to use the extract to develop a new treatment for flu.
The scientists isolated a substance called MC26 from the seaweed.
Using cells taken from animals and fish, they confirmed that this substance effectively fights the influenza virus with about a third of the dosage required for amantadine hydrochloride, a widely available medication for flu.
The scientists said their extract also produced fewer side-effects.
"Our experiments have so far shown that MC26 causes few side-effects, definitely much less than amantadine," said Yuto Kamei, an assistant professor of marine biotechnology and one of those who led the study.
He said he hoped the findings can be used to create a new drug to fight flu and said the scientists were planning further studies to see if it could help tackle other diseases.
"We hope this will result in the creation of a new flu drug," he said.
"We are now focusing our research on influenza because it is so common and we believe there is a big demand and market for it.
"But the substance might fight other viruses, maybe HIV. That's something to be confirmed through further research."
However, he acknowledged that these could by "years away".
Previous studies on other types of seaweed have also suggested it may have health benefits.
In 1998, British scientists suggested proteins in seaweed could be used to treat cancer.
Researchers in the US have recently started clinical trials to see if a gel made from a type of red seaweed found along the coasts of Nova Scotia and Chile to see if it protects against HIV.
Early tests suggested the gel could help to prevent HIV transmission.