Indian researchers develop herbal formulation that could repel the malaria mosquito

Syed Akbar
Hyderabad: A group of Indian researchers has developed a
herbal formulation that could not only repel the malaria mosquito, but
also kill its eggs and larvae. The herbal extract gains significance
as various species of Anopheles mosquito that transmit different forms
of malaria to human beings have developed resistance of synthetic
insecticides.

The research group comprising Dr G Elango Dr A Abduz Zahir, Dr A
Bagavan and others the Postgraduate and Research Department of
Zoology, CA Hakeem College, Vellore, obtained extract from the leaves
of the trees, Andrographis paniculata, Eclipta prostrata and Tagetes
erecta and used them against the Anopheles species subpictus Grassi.

As many as 30 species of Anopheles mosquito transmit malarial
parasites - Plasmodium species -  to humans. The species, Anopheles
subpictus Grassi transmit Plasmodium vivax, causes the vivax type of
malaria. Both the vector (mosquito) and the parasite (Plasmodium) have
turned resistant to insecticides and anti-biotics respectively.
Tackling Anopheles subpictus mosquito will also help in the control of
filariasis, as it is known to carry the filaria worm too.

"Mosquito control is facing a threat due to the emergence of
resistance to synthetic insecticides. We obtained the ethyl acetate,
acetone and methanol extracts of Andrographis paniculata, Eclipta
prostrata and Tagetes erecta leaves and found that the herbal
formulation repels the adult mosquito from both biting people and
laying eggs in water. The mortality i.e killing of eggs was 100 per
cent if about 1000 mg of the  herbal extract was mixed with one litre
of water and sprayed," the researchers pointed out.

According to them, the extract also deters the mosquito from laying
eggs in water. This eco-friendly formulation will not only prevent
malaria spread, but also check mosquito menace. In India, malaria is
one of the most important causes of direct or indirect infant, child,
and adult mortality with about 1.50 crore people affected annually.
About 20,000 people succumb to malarial fevers.

Synthetic insecticides leave residual effects behind both on
environment and human health, besides helping in vectors and pathogens
generating resistance to chemicals and medicines.