Antioxidants

Oxidative stress and excitotoxicity are key contributors to neuronal damage in various neurodegenerative diseases. Caffeine, a widely used neuroactive compound with moderate antioxidant properties, may benefit from structural modifications to enhance its neuroprotective potential. In this study, a series of novel caffeine derivatives was synthesized and evaluated for antioxidant and potential neuroprotective relevance using in vitro models of oxidative stress and glutamate-induced excitotoxicity in SH-SY5Y human neuroblastoma cells. Antioxidant capacity was assessed using ABTS•⁺ radical cation decolorization and DPPH radical scavenging assays. Most derivatives exhibited strong free radical scavenging activity, surpassing both caffeine and the reference antioxidant Trolox at low concentrations (5 µM). Notably, compounds AL-7, AL-8, AL-9, and AL-10 demonstrated particularly high activity. Cytotoxicity evaluation using the MTT assay revealed low toxicity for all compounds, with calculated IC₅₀ values above 500 µM. Intracellular reactive oxygen species (ROS) levels measured by the DCFH-DA assay showed that several derivatives, especially AL-4, significantly reduced H₂O₂-induced oxidative stress. In neuroprotection assays, compounds AL-0, AL-1, and AL-4 markedly protected against hydrogen peroxide-induced damage, restoring cell viability up to 73%, while AL-7 achieved up to 85% protection against L-glutamate-induced excitotoxicity, outperforming caffeine. In silico SwissADME analysis indicated favorable oral bioavailability, with predicted gastrointestinal absorption and limited blood–brain barrier permeability. Overall, these findings highlight structurally modified caffeine derivatives as promising antioxidant and neuroprotective agents warranting further mechanistic and therapeutic investigation.

Alcohol is a molecule whose multiple effects in living organisms exemplify how profound biological complexity can arise from an exceptionally simple chemical structure interacting with the cellular biochemical machinery. This review was conceived to provide an up-to-date synthesis of the current knowledge on the multifaceted consequences of alcohol oxidative metabolism and alcohol-derived oxidative stress, ranging from disruption of subcellular and cellular homeostasis to impairment of organ function. This study primarily focuses on the consequences of alcohol metabolism and on the mechanisms by which the rise of its main metabolite, acetaldehyde, and of reactive oxygen species (ROS), generates oxidative stress by-products and molecular adducts responsible for compromising cellular energy balance and antioxidant defense mechanisms. In particular, this review aims to provide an exhaustive representation of the mechanisms, causes, and consequences of alcohol oxidative metabolism: this is accomplished by taking into account alcohol-induced modifications of gene expression of cellular antioxidant determinants, the role of epigenetic mechanisms, and that of gene polymorphisms linked to alcohol-dependent oxidative stress and responsible for serious diseases such as, among others, alcoholic hepatitis, cirrhosis, and hepatocellular carcinoma. In addition, this review highlights the role of alcohol oxidative metabolism in the brain, which, in the acute setting, activates the dopaminergic system mainly involved in alcohol reinforcing properties and, upon chronic exposure, contributes to neurodegenerative disorders. Finally, a dedicated paragraph explores autophagy as an integrative mechanism underlying the effects of alcohol-related oxidative stress across multiple organs, including the liver, heart, and brain.

Myocardial ischemia–reperfusion injury (MIRI) is a pathological process in which reperfusion-induced oxidative stress and metabolic derangement further aggravate myocardial damage and blunt the benefit of reperfusion. Ferroptosis is increasingly implicated in MIRI, with the glutathione (GSH)–glutathione peroxidase 4 (GPX4) axis constituting a key antioxidant barrier. Although GSH depletion is recognized as a critical event, its upstream regulation in MIRI remains unclear. Against this background, we investigate the BACH1–CHAC1–GSH pathway as a putative upstream regulatory axis of ferroptosis in MIRI and a potential molecular target. Here, using an oxygen–glucose deprivation/reoxygenation (OGD/R) model in AC16 and the reversibility conferred by the ferrostatin-1, RNA sequencing identified the GSH-degrading enzyme CHAC1 as a modulator that is induced by stress and promotes ferroptosis. Experiments showed that CHAC1 overexpression aggravated OGD/R-induced injury, depleted GSH, suppressed GPX4 and enhanced lipid peroxidation, whereas CHAC1 knockdown was partially protective. N-acetylcysteine (NAC) replenished GSH, restored GPX4 activity and partially rescued CHAC1-driven injury. In a mouse myocardial I/R model, cardiotropic adeno-associated virus-mediated CHAC1 overexpression worsened cardiac dysfunction, enlarged infarct and fibrosis areas, and increased myocardial iron deposition. Dual-luciferase assays revealed that the transcription factor BACH1 activates the CHAC1 promoter, and BACH1 silencing attenuated ferroptosis by suppressing CHAC1 and restoring the GSH–GPX4 axis. Collectively, our data identify the BACH1–CHAC1–GSH axis as an upstream amplifier of ferroptosis in MIRI through glutathione depletion and impairment of GPX4-dependent antioxidant defense. These findings refine the mechanistic link between reperfusion-phase redox imbalance and ferroptosis and highlight BACH1/CHAC1 inhibition or augmentation of GSH precursors as potential cardioprotective strategies in ischemic heart disease.