Histopathological effects of fenugreek (trigonella foenumgraceum)‎ extracts on the larvae of the mosquito culex quinquefasciatus

الملخص EN

Background / Aim : botanical bioactive compounds represent a rich resource for the discovery of novel pesticides that are effective, cheap and environmentally safe.

The main targeted insect pests are mosquito vectors of most serious human and animal diseases in the world, such as the mosquito Culet quinquefasciatus.

Methods : the susceptibility of the 3rd-4th instar larvae of Cx.

quinquefasciatus laboratory colony from Saudi Arabia to an Aqueous as well as an ethanol extract of fenugreek was tested.

Biochemical and histopathologically effects of this extract were studied in the treated larvae.

Results : bioassays showed that larvae are highly susceptible to the two fenugreek water and ethanol extracts ; where 30 % Concentration caused 98 to 100 % mortality, respectively.

The ethanol extract is 1.5-2.5 fold more effective against the larvae compared to the water extract ; 20 % concentration caused about 98 % mortality.

Histopathologically examination showed that the midget, hindgut, muscles and nerve ganglia are the most affected tissues.

These tissues suffered major changes including rupture and disintegration of epithelial layer and cellular vacuolization.

Protein analysis indicated obvious changes in general protein profile of fenugreek-treated larvae compared to control Culex larval profile.

The changes include the loss of protein bands of high molecular weights between 75 and 212 KD.

A group of bands of molecular weights between 28-39 KD appeared in treated larvae.

The overall changes show the gain of one band in treated larvae (total bands = 9) compared to the control mosquito profile (total bands = 8).

Conclusion : these results showed that fenugreek water and ethanol extracts have high parricidal effect against mosquito larvae under laboratory conditions.

Treatment of larvae with water extract caused prominent effects on various body tissues including the midget and nervous system as well as total protein content.

The active ingredients in plant extracts have important effects on physiological processes of the mosquito and therefore could implicate its life cycle and victoria capacity for disease transmission and thus present new source for the development of insecticides against mosquitoes and other vectors.