Tuesday, May 27, 2008

S&T Watch-7: "New Powerful Insect Repellants"

American researchers have identified several potential insect repellants that are three times more potent than DEET, the active ingredient in most tick and insect repellents, a study released on Monday said.

In laboratory tests, the new compounds protected human volunteers from mosquitoes for periods two to three times longer than DEET (n,n-diethyl-m-toluamide), which has served as the gold standard of repellents for more than 50 years.

While DEET repellents offer broad-based protection from a variety of insects, mosquitoes continue to spread diseases such as malaria, and some mosquitoes can bite through an application of DEET, the paper said.

“It would be good to have more effective repellents that protect against a greater number of insect species,” said Ulrich Bernier, a research chemist with the Mosquito and Fly Research Unit of the U.S.Department of Agriculture (USDA), who worked on the project.

Back in the 1940s, it took USDA scientists a decade to screen 40,000 chemical compounds in a search for new and more effective insect repellents. That quest ultimately led them to DEET.

USDA investigators were able to screen thousands of potential compounds using a drug discovery computer program that uses information about chemical structures and insect receptors to predict repellents’ effectiveness against mosquitoes.

The program allowed the scientists to winnow a field of 2,000 compounds down to just 34, which they then tested on human volunteers in the laboratory. The volunteers were exposed to mosquitoes for 17.5 days, some of the new compounds lasted up to 73 days. - AFP

Courtesy: The Hindu, Madurai, May 27, 2008

Grateful thanks to AFP and The Hindu.

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