Modern approaches of computer support for virtual screening of antioxidants

For the first time, the mathematical and theoretical foundations of a complex approach to the creation of a computer program for the virtual screening of NO scavengers in a number of newly synthesized compounds were developed. Approaches to the implementation of the software complex are described.
In our work, for the first time, the antioxidant activity of 532 xanthine derivatives was evaluated in vitro for NO inhibition. For the first time, with the help of semi-empirical quantum chemical methods, the main descriptors of the frontier molecular orbitals of xanthine derivatives have been substantiated
by their influence on the ability of these compounds to bind NO. This research aims to assess the in vitro antioxidant properties of 532 xanthine derivatives with regard to NO inhibition. The dependence of antioxidant activity on the quantum chemical parameters of xanthine derivatives was analyzed using machine learning algorithms using the following models: Linear Regression, Support Vector Machine Regression, Random Forest Regression, Gradient Boosting Regression, K-Nearest Neighbor Regression. As a result of our analysis, we tested several models for solving regression problems. The best models without optimization turned out to be the "Support Vector Machine Regression" and "K-Nearest Neighbors Regression" models. When optimizing the studied models, the Gradient Boosting Regression model showed the best generalizing ability with an error within 16%. This model can be used for the prediction of antioxidant activity based on quantum chemical parameters. The model's quality can be further improved by increasing the training and test samples, as well as expanding the features to deepen the model and improve the generalization ability. A program of virtual screening of substances with the properties of NO scavengers has been developed and created. In the process of testing the new synthesized xanthine derivatives, a computer program made it possible to predict the most pronounced properties of the NO scavenger in 8- enzylaminotheophilinyl-7-acetic acid hydrazide (C-3). In vitro experiments confirmed the prediction of the properties of the NO scavenger in C-3 (267.3%). Addition of C-3 (10 -5 M) to the incubation mixture leads to a decrease in nitrotyrosine by 45% and oxidized glutathione by 53.2% concomitantly with an increase in the concentration of reduced glutathione by 43.8% and increase in the activity of GSH-dependent enzymes - GPR by 337% and GR by 195% (p < 0.05). It should be noted that the antioxidant effect of C-3 is accompanied by an increase in concentration of HSP ₇₀ by 34.7%. By regulating the level of NO and its cytotoxic forms, C- 3 is able to reduce the suppression of GSH, which determines the concentration of HSP ₇₀ . In terms of potency, C-3 is significantly superior to Mexidol (10 ^-5 M). The obtained results in vitro confirm the results of the NO scavenger’s C-3 compound obtained as a result of the virtual screening.