Chemometrics Studies Larvicidal Compounds against Aedes aegypti (original) (raw)
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Chemosphere, 2011
In the search for larvicidal compounds against Aedes aegypti L. (Diptera: Culicidae), a collection of monoterpenes were selected and evaluated. R-and S-limonene exhibited the highest larvicidal potency (LC 50 = 27 and 30 ppm, respectively), followed by c-terpinene (LC 50 = 56 ppm) and RS-carvone (LC 50 = 118 ppm). Structural characteristics which may contribute to the understanding of the larvicidal activity of monoterpenes were empirically identified. The presence of heteroatoms in the basic hydrocarbon structure decreases larvicidal potency. Conjugated and exo double bonds appear to increase larvicidal potency. Replacement of double bonds by more reactive epoxides decreases the larvicidal potency. The presence of hydroxyls in the cyclic structure resulted in decreased potency, probably due to increased polarity indicanting that lipophilicity seems to play an important role in increasing the larvicidal potency in this set of compounds.
Molecular diversity, 2010
A topological-mathematical model based on multilinear regression analysis has been built to search new terpenoid actives as mosquito repellents. The structural depiction was performed using topological indices, and a four-variable model for the prediction of corrected repellent ratio (r (2) = 0.9672, Q (2) = 0.9435) was selected. The model was checked by cross-validation, internal validation, and randomization test. The results confirm its capability to predict the property analyzed. After carrying out a virtual screening upon such a model, new structures with potential repellent activity against mosquitoes are proposed.
Journal of Medical Entomology, 2009
This research studied 31 volatile compounds for indoor control of the medically important mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say. Only adult female mosquitoes were tested. The test compounds were from six families that included Þve heterobicyclics, eight formate esters, formic acid (a hydrolyzed metabolite of formate esters), eight acetate esters, four propionate esters, three butyrate esters, and two valerate esters. Also, the organophosphate compound dichlorvos (DDVP) was tested as a positive control. Cx. quinquefasciatus was generally more susceptible than Ae. aegypti. Cx. quinquefasciatus was most susceptible to a subset of heterobicyclics and formate esters (rank: n-butyl formate Ͼ hexyl formate ϭ dihydrobenzofuran ϭ menthofuran ϭ heptyl formate ϭ ethyl formate). Ae. aegypti was most susceptible to a subset of formate esters (rank: methyl Ͼ n-butyl Ͼ propyl ϭ ethyl ϭ hexyl). The most active materials against both species had LC 50 s of 0.4 Ð1 mg active ingredient per 0.5 liter of air volume (0.8 Ð2 mg/liter), which is 50-to 60-fold less toxic than dichlorvos (an organophosphate insecticide that is being phased out from indoor use). In relation to Drosophila melanogaster Meigen, both mosquito species were generally more susceptible to formate esters but more tolerant of heterobicyclics. Generally, the most toxic compound against all dipterans tested to date is n-butyl formate, whereas menthofuran is additionally toxic against Cx. quinquefasciatus and D. melanogaster. Finally, the toxicity differences between species point to the potential for differential toxicity among mosquito genera/species, suggesting that further studies of a number of mosquito species might be warranted.
Molecules
Aedes aegypti is a vector for the arbovirus responsible for yellow fever, Zika and Chikungunya virus. Essential oils and their constituents are known for their larvicidal properties and are strong candidates for mosquito control. This work aimed to develop a quantitative structure–activity study and molecular screening for the search and design of new larvicidal agents. Twenty-five monoterpenes with previously evaluated larvicidal activity were built and optimized using computational tools. QSAR models were constructed through genetic algorithms from the larvicidal activity and the calculation of theoretical descriptors for each molecule. Docking studies on acetylcholinesterase (AChE) and sterol carrier protein (SCP-2) were also carried out. Results demonstrate that the epoxide groups in the structure of terpenes hinder larvicidal activity, while lipophilicity plays an important role in enhancing biological activity. Larvicidal activity correlates with the interaction of the sterol-...
Croatica Chemica Acta, 2008
Quantitative structure-activity relationship (QSAR) modeling of 40 DEET-related mosquito repellents was carried out using calculated molecular descriptors. When the four different classes of descriptors (topochemical, topostructural, geometrical and quantum chemical) were used in a hierarchical fashion, topochemical descriptors were found to explain much of the variance in the data and this indicated the importance of the chemical nature of the atoms and groups towards repellency of these compounds. Ridge regression (RR) outperformed partial least square regression (PLS) and principal component regression (PCR). We also used descriptor thinning via a modified Gram-Schmidt algorithm prior to ridge regression. This resulted in a four-parameter model with a 20-fold cross-validated R 2 of 0.734. The q 2 (R 2 cv) reported here is the "true-q 2 " because the descriptor thinning was embedded within the cross-validation step. Inclusion of any calculated physicochemical property (secondary descriptor) did not result in improvement of the models built with the calculated molecular descriptors (primary descriptors). This result has great implications in the QSAR assisted design of new mosquito repellents because calculation of the primary descriptors does not require any input other than the molecular structure.
Synergistic terpene combinations as larvicides against the dengue vector Aedes aegypti Linn
Drug Development Research, 2019
Most of the essential oils (EO) known for mosquitocidal activity contain terpenes as part of their chemical constituents. In this study, four monoterpenes namely γ-terpinene (T), R-(+)-limonene (L), carvacrol (C), and trans-anethole (A) were screened against late third instar Aedes aegypti Linn. larvae singly and in combination to find out the synergistic interaction. The monoterpenes γ-terpinene, R-(+)-limonene, trans-anethole, and carvacrol showed larvicidal activity with LC 50 values of
Advances in Infectious Diseases, 2015
Nowadays, dengue fever, a mosquito-borne tropical disease, has become widely distributed in Brazil. In order to prevent such disease, the population of Aedes aegypti mosquito has to be controlled. Then, the aim of this study is to assess the toxicological effects of phenolic compounds against dengue mosquitos. Hence, the larvicidal activity and toxicity of phenolic compounds against Ae. aegypti larvae and A. salina, are evaluated, respectively. The phenolic compounds 2,6-diiodophenol and 4-chloro-2,6-diiodophenol have different toxicity and larvicidal activity. The compound 4-chloro-2,6-diiodophenol shows the highest toxicity for larvae of Ae. aegypti, exhibiting higher toxicity than 2,6-diiodophenol. Although less toxic than Temephos ® (organophosphate), the phenolic compounds evaluated by this research, are proved to be effective against Ae. aegypti larvae. This study demonstrates the importance of controlling the dengue mosquito, considering toxicological aspects of phenolic compounds to prevent environmental impacts.
Proceedings of MOL2NET'21, Conference on Molecular, Biomedical & Computational Sciences and Engineering, 7th ed., 2021
The Aedes aegypti mosquito belongs to the order Diptera and is one of the main vectors of transmission of etiological agents that cause several diseases. This mosquito can transmit diseases such as dengue, yellow fever, Zika, chikungunya, among others. The aim of this study was combining structure-based and ligand-based virtual screening (VS) techniques to select potentially larvicidal active molecules against Ae. aegypti from in-house secondary metabolite dataset (SistematX). From the ChEMBL database, we selected a set of 161 chemical structures with larvicidal activity against Ae. aegypti to create random forest models with an accuracy value higher than 82% for crossvalidation and test sets. Afterward, the ligandbased virtual screen selected 38 secondary metabolites. In addition, a structure-based virtual screening was also performed for the 38 molecules selected. Finally, using consensus analyzes approach combining ligand-based and structure-based VS, five molecules were selected as potential larvicidal against Ae. aegypti.