Will medicinal herbs hold an answer for avian flu?

Progress in search for 'bird-flu herbs'

Identifying the right herb as an alternative treatment for the bird-flu virus could take years, as it would not be simple to narrow down the list and complete testing, researchers have said.

Until recently, they were concerned about the cost of using the conventional tissue-culture method on 30,000 substances derived from 150 types of herbs to decide which could be effective.

But a new development has been helping in the fight - Kasetsart University's "Chemiebase", an Internet database of herbal extracts which could be used in simulating tests on whether certain herbal substances were worth further trial.

Containing about 100,000 3D chemical structures of herbal substances, the new database allows scientists to find herbal medication to fight bird flu.

With this "virtual screening" of 30,000 structures, it was found that only about 40 were actually worth further investigation, according to Chak Sangma of Kasetsart University's Chemino-fomatic Research Unit said.

This technique has just been introduced to herbal research in Thailand, although the programme has been widely used in the other countries such as China and India where herbal research is very advanced, said Chak, who is involved in Biotec's research.

Out of the 40 likely substances taken from a few types of plants, only one turned out to be effective in suppressing the H5N1 strain of bird flu, said Prof Pilaipan Puthavathana of Siriraj Hospital's Department of Microbiology, who tested the substances for Chak.

"This is the way to go. Even with the help of this programme, it took me several months to finish," she said. "I can't imagine how long and how impractical it would be to do a tissue culture on all of those substances to eventually get only one worth further investigation."

Developed by Kasetsart's Facul-ty of Science, the database is available free of charge at "http://chemiebase.ku.ac.th".

The researchers have decided to withhold the name of the herbal substance which in preliminary tests has proven effective in the fight against the bird-flu virus.

They were also still testing a few other substances which showed promise like the one already tested by Siriraj, according to Chak, who warned: "Don't hold your breath. It's not time to open the champagne just yet."

The researchers also have to bear in mind a drug that can effectively fight the virus in the laboratory might not always work when used on humans. So it could take 10 to 15 years to develop one herbal drug.

Arthit Khwankhom

The Nation