Background: Reactive oxygen species (ROS) are important mediators in a number of degenerative diseases. Oxidative stress refers to the imbalance between the production of ROS and the ability to scavenge these species through endogenous antioxidant systems. Since antioxidants can inhibit oxidative processes, it becomes relevant to describe natural compounds with antioxidant properties which may be designed as therapies to decrease oxidative damage and stimulate endogenous cytoprotective systems. The present study tested the protective effect of two xanthones isolated from the heartwood of Calophyllum brasilienses against FeSO₄-induced toxicity. Methods: Through combinatory chemistry assays, we evaluated the superoxide (O₂ ^●—), hydroxyl radical (OH^●), hydrogen peroxide (H₂O₂) and peroxynitrite (ONOO^—) scavenging capacity of jacareubin (xanthone III) and 2-(3,3-dimethylallyl)-1,3,5,6-tetrahydroxyxanthone (xanthone V). The effect of these xanthones on murine DNA and bovine serum albumin degradation induced by an OH• generator system was also evaluated. Additionally, we investigated the effect of these xanthones on ROS production, lipid peroxidation and glutathione reductase (GR) activity in FeSO₄-exposed brain, liver and lung rat homogenates. Results: Xanthone V exhibited a better scavenging capacity for O₂ ^●—, ONOO^- and OH^● than xanthone III, although both xanthones were unable to trap H₂O₂. Additionally, xanthones III and V prevented the albumin and DNA degradation induced by the OH^● generator system. Lipid peroxidation and ROS production evoked by FeSO₄ were decreased by both xanthones in all tissues tested. Xanthones III and V also prevented the GR activity depletion induced by pro-oxidant activity only in the brain. Conclusions: Altogether, the collected evidence suggests that xanthones can play a role as potential agents to attenuate the oxidative damage produced by different pro-oxidants.

Sleep deprivation is a recognized risk factor for neuroinflammatory and neurodegenerative disorders. Dopamine signaling through D2 receptors (DRD2) has emerged as a potential immunomodulatory pathway in the central nervous system. The present study investigated whether activation of DRD2 by quinpirole (QUIN) modulates astrocytic and microglial responses and NF-κB nuclear translocation in a murine model of rapid eye movement sleep deprivation (RSD). Male CD1 mice were subjected to 72 h of RSD and treated with QUIN (2 mg/kg/day). GFAP, Iba-1, and NF-κB expression were evaluated in hippocampal subregions (CA1, CA3, dentate gyrus) and the medial parietal cortex using immunofluorescence and confocal microscopy. RSD increased GFAP and Iba-1 expression and induced morphological changes consistent with glial activation. Notably, RSD increased NF-κB nuclear expression in microglia. QUIN administration reduced Iba-1 expression, attenuated microglial morphological alterations, and reduced NF-κB nuclear expression across all analyzed regions, even in RSD-subjected mice. These findings suggest that DRD2 activation exerts anti-inflammatory effects in the brain during REM sleep deprivation and that dopaminergic signaling may represent a key target for neuroinflammation associated with sleep loss.