Obtenção de modelos QSAR na plataforma livre de computação em nuvem OCHEM e uma aplicação para atividade acaricida de monoterpenos

Abstract

The present work focuses in using the resources of the free access cloud computing web platform OCHEM - English Online Chemical Modeling Environment, designed for data storage, development of models and publication of chemical information. As an example of application on the platform, we sought to obtain QSAR models - Quantita-tive Structure-Activity Relation for insecticidal activity on the species of Spider Mite (Tetranychus Urticae), a common pest in family farming in the Northeast region of Bra-zil, from a series of compounds of the monoterpene class: α-pinene, p-cymene, β-pinene, menthol, α-terpineol, geraniol, R-limonene, 1-8-cineole, R-linalool, terpenyl ac-etate, and terpinolene and 4- (S) ter-pineol. To this end, we carried out a literature review on the monoterpenes usage in agriculture pest control, as well as a review of the Quantitative Structure-Activity Relation-ship method, QSAR. For the application of the OCHEM platform to obtain QSAR models for the series of monoterpenes, we per-formed the molecular modeling of the series compounds by methods of Quantum Chemistry, generating the molecular structures in order to feed the OCHEM platform, to calculate the molecular descriptors and obtain of QSAR models. We explored differ-ent sets of descriptors as well as different types of machine learning methods, such as Multiple Linear Regression (MLR), Partial Least Squares (PLS) and Neural Networks (NN - Neural Networks). The models so obtained for the series under study, however, did not have sufficient statistical quality, probably due, firstly, to the small number of compounds in the training set with available experimental data and, also, to a likely strong degree of non-linearity present in the relationship between the chosen de-scriptors and the activity.