CIMO - Artigos em Revistas Não Indexados à WoS/Scopus
Permanent URI for this collection
Browse
Browsing CIMO - Artigos em Revistas Não Indexados à WoS/Scopus by Author "Abreu, Rui M.V."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- Python-based QSAR modeling protocol for antioxidant activity: a case-study using a library of di(hetero)cyclic amines or amidesPublication . Mateus, Cristiano; Abreu, Rui M. V.; Abreu, Rui M.V.; Mateus, CristianoConstructing a QSAR model involves several critical steps, including chemical structure preparation, molecular descriptor calculation and selection, and model development and validation. This study presents a comprehensive methodology for preparing QSAR models using freely open-source software tools. A detailed, stepby- step protocol outlines the entire process, from compound library preparation to statistical validation. As a case study, we developed a QSAR model to predict the antioxidant activity, specifically radical scavenging activity, of 70 di(hetero)aryl amine and amide compounds. Molecular descriptors (12,072 total) were calculated using the OCHEM platform, and PyQSAR built-in tools were used for descriptor selection and model construction. Four key descriptors (B06[C-O], Eig04_AEA(dm), JGI2, and J_Dz(p)) were selected to develop a MLR model with strong statistical performance (Q2CV = 0.8676, RSRCV = 0.3518). Internal validation showed strong predictive stability, while external validation demonstrated the model’s generalizability with a Q2EXT > 0.5. This study not only demonstrates the application of a freely open-source QSAR approach but also contributes to ongoing efforts in identifying and designing potent antioxidant agents with potential therapeutic applications. All relevant files and the detailed protocol are provided, allowing other researchers to replicate the antioxidant QSAR model and apply the methodology to develop QSAR models for other compound libraries and biological activities.
- Stress oxidativo, antioxidantes e fitoquímicosPublication . Ferreira, Isabel C.F.R.; Abreu, Rui M.V.A manutenção do equilíbrio entre a produção de radicais livres e as defesas antioxidantes (enzimas e moléculas não enzimáticas) é uma condição essencial para o funcionamento normal do organismo. Quando este equilíbrio tende para a produção de radicais livres dizemos que o organismo está em stress oxidativo, e nestas situações os radicais livres em excesso podem oxidar e danificar lípidos celulares, proteínas e DNA, inibindo a sua função normal e conduzindo a várias doenças. Em organismos aeróbios, os radicais livres são constantemente produzidos durante o funcionamento normal da célula, na maior parte sob a forma de espécies reactivas de oxigénio (ROS) e de nitrogénio (RNS). A exposição dos organismos a radicais livres, conduziu ao desenvolvimento de mecanismos de defesa endógenos para os eliminar. Estas defesas são a resposta da evolução à inevitabilidade da existência de ROS em condições aeróbias. Alguns produtos naturais com actividade antioxidante, podem auxiliar o sistema protector endógeno. Nesta perspectiva, os antioxidantes presentes na dieta assumem grande importância como possíveis agentes protectores, reduzindo os danos oxidativos. São aqui descritos alguns desses agentes antioxidantes, os fitoquímicos, compostos bioactivos provenientes de diferentes partes de plantas (sementes, cereais, vegetais, frutos, folhas, raízes, especiarias, ervas) envolvidos na redução do risco de doença, como o cancro. Foram já identificados mais de 5000 fitoquímicos, no entanto, grande parte destes compostos é ainda desconhecida, sendo a sua identificação essencial para a compreensão da sua contribuição na saúde, ao serem incluídos na dieta. Maintenance of equilibrium between free radical production and antioxidant defences (enzymatic and non enzymatic) is an essential condition for normal organism functioning. When this equilibrium has a tendency to the production of free radical we say that the organism is in oxidative stress. In this situation, excess free radicals may damage cellular lipids, proteins and DNA, inhibiting his normal function and leading to various diseases. In aerobic organisms, the free radicals are constantly being produced during the normal cellular functioning, mainly in the form of Reactive Oxygen Species (ROS) and Reactive Nitrogen Species (RNS). Exposition of the organism to free radicals has led to the development of endogenous defence mechanisms to eliminate them. These defences were the response of evolution to the inevitability of ROS production in aerobic conditions. Natural products with antioxidant activity may help the endogenous defence system. In this perspective the antioxidant present on the diet assume a major importance as possible protector agents reducing oxidative damage. Phytochemicals with antioxidant activity, obtained from different plant parts (seeds, cereals, vegetables, fruits, leaves, roots, spices, herbs), and involved in disease risk reduction are review. More than 5000 phytochemicals were already discovered, but most of these compounds remain yet to be discovered. Their identification and the study of their contribution to health is essential.