By IANS
Kolkata : Berries of a wild weed used in ayurvedic formulations could help eliminate dengue-spreading mosquitoes, resistant to synthetic insecticides, according to a study.
Two-fifths of the global population is at risk from dengue, characterised by high fever, pain and rashes. Dengue haemorrhagic fever is a potentially lethal complication, mainly affecting children.
The weed, called Solanum villosum (S. villosum), is a member of the nightshade family known for its medicinal properties and is commonly used as an ayurvedic herb.
Researchers at Burdwan University in West Bengal used juice and extracts from the berries of S. villosum on mosquitoes known to spread a number of viruses, including dengue fever and yellow fever.
They found that S. villosum was particularly effective in eliminating the larvae of the S. aegypti mosquito. Although it was not as potent as the insecticide Malathion, they suggest that its extracts have the potential to act against mosquitoes in stagnant water.
The next step is to identify the active compounds in the berries and to test whether these are effective in field trials.
“We found that these plants produce two types of phytochemicals,” said researcher Goutam Chandra. “The most interesting are the secondary phytochemicals, such as steroids, terpenoids, flavonoids and alkaloids. These act as a repellent which protect against the lethal effects of the larval mosquitoes.”
A number of plants have been reported for their anti-mosquito potency. Most studies report the active compounds to be steroidal saponins, which are thought to kill larvae by interfering with their cuticle membranes. However, only a few plant extracts have moved from the laboratory to field use.
Mosquitoes responsible for spreading disease are increasingly becoming resistant to synthetic insecticides such as Malathion.