Minden Press-Herald

Oct 01st

From worst to best


Salvinia compound may bring hope to cancer patients

It has been called the worst vegetation known to man, but recent research findings at Stephen F. Austin State University's National Center for Pharmaceutical Crops may soon change the way people think about giant Salvinia.

Researchers have discovered that extracts of giant Salvinia can inhibit the growth of human tumor cells with minimal damage to normal cells.

"I was very surprised in the beginning to find this compound in the plant," said Dr. Shiyou Li, research professor and director of the center located in the Arthur Temple College of Forestry and Agriculture at SFA. Li has worked on researching invasive plants of all varieties for 21 years.

In 2005, his team identified leaves of Sweetgum as a high-yielding alternative source for imported shikimic acid. A limited supply of shikimic acid is the main reason for the global shortage of the antiviral drug Tamiflu.

To date, more than 30 compounds, including four new compounds, have been isolated from giant Salvinia. One of those may have potential to help alleviate inflammation associated with arthritis and other diseases.

Giant Salvinia is a fern species native to Brazil. It is one of the most widespread and environmentally, economically and socially destructive invasive plant species in the world and has created such a problem with local lakes that a task force (the Bistineau Task Force) was formed to battle it.

In May, BTF was fighting 40 acres of the weed. That number has significantly reduced thanks to spraying and drought, but BTF knows it won't stay down for long.

"We are still researching biocontrol – such as a more cold tolerant weevil – as well as new chemical conglomerations," said Evan Thames of the Louisiana Department of Wildlife and Fisheries and BTF. "So far there have not been any ecosystem impact studies, but it has been thrown around that we might need to start such a study."

There are no natural controls to halt the spread of giant Salvinia. It is highly invasive and can double in size every five to seven days. The plant can regenerate even after severe damage or drying.

The explosive growth of giant Salvinia not only adversely affects the natural ecological system of the infested region, but it also causes considerable economic damage and sanitation problems.

Dr. Li said there might be another issue with the plant.

"What worries me is this plant is blooming and sooner or later we may see a parasitic disease known as Snail Fever Disease," he said.

Snail Fever Disease, or Schistosomiasis is caused by several species of snails that carry a parasitic worm that thrive in giant Salvinia plants.

The disease can damage internal organs and, in children, impair growth and cognitive development and is the second most devastating parasitic disease after malaria.

While it is most commonly found in Asia, Africa and South America, Dr. Li thinks it could reach America.

"This plant is in its perfect environment here in the south," said Li. "Because of the potential for this parasite to make it here, getting rid of the plant is very important."

Li is interested in coming to Webster Parish to take samples of the giant Salvinia. Li said he thinks the variety found locally and the one in Texas are the same, but there could be some significant differences.

"Their chemical compounds may be different because of the different nutrients they take in due to the different ecosystems they thrive in," he said.

After the initial discovery, M.D. Anderson Cancer Clinic researchers joined in and are now doing studies on molecular makeup. The next step, Li said, is hopefully toward animal testing of medication made from the compounds.

Part of the NCPC project is funded by the National Institute of Food and Agriculture of the U.S. Department of Agriculture.

"I think nature gave us this disaster to bring us the good," said Dr, Li about the giant Salvinia.






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