The ubiquitous white pine isn’t just the source of Maine’s nickname.
It turns out the tree’s aromatic needles are a source for a rare starter material in the anti-flu drug Tamiflu, researchers in the University of Maine chemistry department have discovered.
They reported their findings to the American Chemical Society in Boston last month and are getting ready to publish their work. The researchers hope to attract interest from the state’s forest products industry to develop a market for shikimic acid, as they refine their technique for extracting the substance from pine needles.
“There are a heck of a lot of conifer needles just lying out in the forest,” said Ray Fort, a chemistry professor who has worked on the research project for four years with fellow chemistry professor Barbara Cole, graduate student Gedivinne Nelmini and several undergraduate and high school students.
Tamiflu was one of only two drugs recommended last flu season by the federal Centers for Disease Control and Prevention. Manufactured by the Roche drug company, its generic name is oseltamivir.
Shikimic acid is produced naturally by all plants and bacteria, said Fort. But only a few plants store it so that it can be extracted. For years, scientists knew that conifer needles contained more shikimic acid than most plants, but no one was particularly interested. That changed with the bird flu scares and the swine flu pandemic in the last decade.
The major source of shikimic acid has been star anise, a small tree that bears a hard, star-shaped fruit that is prized as a spice. Star anise grows only in a few mountainous regions of northwest China, and it’s very expensive. During the peak of the swine flu pandemic last year, the price soared to $700 a kilogram –about 2.2 pounds.
This isn’t the first time scientists have looked to iconic Maine resources for profits.
A group in Bangor is trying to develop technology to create plastics out of potatoes. Old Town Fuel and Fiber is working with the University of Maine to make ethanol from Maine trees. And a University of Maine food scientist, Alfred Bushway, has experimented with blueberry purees and powders as a nutritional and flavor enhancement in meat patties.
Fort and Cole got the idea for their research from Greg Cyr, who owned a lumber company in Ashland. A few years ago, Cyr read about an effort by a Canadian company to extract shikimic acid from used Christmas trees.
“He came to us and said, ‘This collecting Christmas trees is hogwash. It’s very labor-intensive, and here we have this logging industry that is cutting trees all the time and they don’t use the foliage,’” Cole said.
With a $10,000 seed grant from the Maine Technology Institute, Cyr, who has since moved on, and the researchers set out to test various species of conifer foliage for shikimic acid. White pine needles, which are plentiful, turned out to be an excellent source.
The acid makes up 3.5 percent of the dry weight of the needles, compared with 6 percent in star anise. The needles of the tamarack larch, also known as the hackmatack in Maine, also are good sources of the acid.
Scientists basically extract the acid by brewing a pine needle tea. “The lab smells really good, like Christmas in July,” said Fort.
They have discovered that the needles should be fairly fresh, and they have experimented by brewing the needles in a gigantic tea bag, stitched together from muslin by Cole.
The researchers are now looking at whether more of the acid is present at certain times in the growing season, and are working to speed up the extraction process by using microwaves.
They envision an extraction unit mounted on the back of a truck to cook the needles right in the woods. “It takes no real skill to do the extraction,” Fort said.
Patrick Strauch, executive director of the Maine Forest Products Council, said he is intrigued by the research.
He said that extracting shikimic acid from pine needles could be a source of extra income for logging companies, and that the chemical properties of trees have potential for the forest industry in Maine.
“There is a future for this,” he said.
Staff Writer Beth Quimby can be contacted at 791-6363 or at: firstname.lastname@example.org