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Dengue fever is one of the main public health problems in the world. Many mosquitoes have developed resistance to the conventional insecticides used. Thus, the search for vegetable extracts and natural substances as alternative insecticides has increased. In this study, chemometric methods were employed to classify a group of terpenoid and phenylpropanoid compounds with biological activity against the larval of the A. aegypti mosquitoes. The AM1 (Austin Model 1) method was used to calculate a set of molecular descriptors (properties) for the studied compounds. Then, the descriptors were analyzed using the following methods of pattern recognition: Principal Component Analysis (PCA) and Hierarchical Clustering Analysis (HCA). The PCA and HCA methods have shown to be very effective for the classification of the study compounds in two groups (active and inactive). The electronic variables EHOMO-1, EHOMO-2, ELUMO, ELUMO+2, and the structural LogP were used to classify as active and inactive compounds. In most studied compounds, the variables responsible for separating active from inactive compounds were electronic descriptors. Thus, it can be concluded that electronic effects play a fundamental role in the interaction between biological receptor and terpenoid and phenylpropanoid compounds with activity against larval A. aegypti mosquitoes.

We study theoretically the amodiaquine-adenine and amodiaquine-guanine adducts formation using Density Functional Theory (B3LYP) and the 6-31G(d) basis set for the geometry optimizations and 6-31+G(d,p) for the analysis of the global indexes: electrophilicity (w), electronic chemical potential (m), hardness (h) and softness (S), based in the Frontier Molecular Orbital Theory – FMO. Local softness for nucleophilic reaction (sk+) sites over guanine was evaluated using Fukui function (f k). We also evaluated the guanine Electrostatic Potential (EP) values using the (MSK) charge scheme. The theoretical calculations had demonstrated that the amodiaquine has greater electronic affinity for the guanine, with irreversible formation of the amodiaquine-guanine adduct, as reported before on a previous experimental work.