New Natural Compounds Combat Mosquitoes

It's no secret that mosquitoes are the cause of a lot of suffering in the world. Malaria, Dengue fever, chikungunya, and West Nile are just a few names infamously associated with those little bloodsuckers that we all hate. Now researchers have discovered a number of natural compounds found in some plants that could help limit insect growth and mosquito populations.

It's not exactly like the world doesn't have many means of controlling mosquito populations already. Pesticides have long been a last resort that third-world countries will still employ. Other, more modern and less environmentally harmful approaches have also started seeing use, including experimental DNA manipulation and designer bacterial infection. Many countries are even introducing sterile males into populations to help "dilute" the number of successful reproducers.

Researchers have even identified essential reproductive regulators in female mosquitoes, which they hope to target in what essentially could be called "mosquito birth control."

However, many of these options pose the threat of eliminating mosquitoes entirely, and most involve a great deal of tinkering with nature. Concerns remain that the use of some of these methods could gravely affect ecosystems in unforeseen ways.

This can't be said, however, for juvenile hormone antagonists (JHANs) - compounds naturally found in some plants that make up their innate resistance mechanisms against insect herbivores.

According to a study recently published in the journal Proceedings of the National Academy of Science, JHANs target a growth hormone in larvae that is exclusive to insects. By introducing JHAN compounds to mosquito and other pesky bug populations, their numbers can be limited without threatening other organisms or contaminating environments.

In a collaboration with Korean scientists, researcher Alexander Raikhel and his colleagues screened 1,651 plant species and chose active JHANs from these plants. Five JHANs from two plants in particular were found to effective at raising the death rate in yellow fever mosquito larvae.

"Our experiments showed that these five JHANs are effective against yellow fever mosquitoes," Raikhel said in a statement. "These newly discovered natural molecules could lead to the development of a new class of safe and effective pesticides to control mosquitoes."

He added that now that these compounds have been identified, his lab's Korean collaborators have begun investigating how to effectively employ them to control agricultural pest populations as well.

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