Mosquitocidal effect of monoterpene ester and its acetyl derivative from Blumea mollis (D. Don) Merr against Culex quinquefasciatus (Diptera: Culicidae) and their insilico studies

The present study was conducted to assess the mosquitocidal efficiency of compound isolated from Blumea mollis (D. Don) Merr against Culex quinquefasciatus. Eggs and larvae of Cx. uinquefasciatus were exposed to different concentrations 0.5, 1.0, 1.5 and 2.0 ppm of compounds prepared using DMSO. Compound 1 was identified as (4R, 5S)-4-hydroxy-7-tigloyloxy carvotanacetone, from which new derivative was synthesized and confirmed as (4R, 5S)-4-acetoxy-7-tigloyloxy carvotanacetone. Both the compounds presented larvicidal and ovicidal activities. Compounds 1 and 2 at 2-ppm concentration showed 64% and 78% larval mortality in 24 h, respectively. The LC50 and LC90 values of compounds 1 and 2 on Cx. quinquefasciatus larvae were 1.73, 1.27 and 4.59, 3.33 ppm, respectively. The eluted compound 1 and synthesized compound 2 presented 68% and 77% of ovicidal activity, respectively, against eggs of Cx. quinquefasciatus at 120 h post-treatment. Histopathological studies of the compound-treated larvae revealed serious damage on the larval midgut cells. Furthermore, compounds 1 and 2 was tested for toxicity study and the results showed both the compounds were found to be harmless to nontarget organism Poecilia reticulata. Computational analysis of compound 2 showed strong binding interaction with the AChE1 of Cx. quinquefasciatus. These results clearly suggest that compounds from Blumea mollis could act as good mosquitocidal agents against Cx. quinquefasciatus and compound 2 was first time reported.

Automated summary

The study evaluated the mosquitocidal efficiency of compounds isolated from Blumea mollis against Culex quinquefasciatus, showing larvicidal and ovicidal activities. Compound 2 was reported for the first time and caused serious damage to the larval midgut cells. Toxicity tests indicated both compounds were harmless to the non-target organism Poecilia reticulata, with compound 2 showing strong binding interaction with the AChE1 of Cx. quinquefasciatus.