Therapeutic Potential of Natural Compounds for Brain Ischemia-Reperfusion Injury.

Brain ischemia-reperfusion (I/R) injury, commonly occurring in ischemic stroke and post-cardiac arrest scenarios, results in complex secondary damage involving oxidative stress, inflammation, apoptosis, and blood-brain barrier (BBB) breakdown. Despite decades of research, no pharmacological agent has yet been clinically approved for post-I/R neuroprotection. Natural compounds have recently gained attention for their multimodal therapeutic potential, including antioxidant, anti-inflammatory, anti-apoptotic, and neuroregenerative effects. This review highlights nine promising candidates-resveratrol, curcumin, quercetin, berberine, ginkgolide B, baicalin, naringin, fucoidan, and astaxanthin-that exhibit efficacy in experimental models of I/R injury when administered after the insult. Their chemical structures, pharmacokinetics, and mechanisms of action are described in detail, focusing on key signaling pathways such as nuclear factor erythroid 2-related (Nrf2), nuclear factor kappa B (NF-κB), phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), and brain-derived neurotrophic factor (BDNF). Importantly, we outline the selection criteria for these compounds, including demonstrated neuroprotective efficacy, mechanistic clarity, and translational feasibility. While several challenges remain-such as limited bioavailability, BBB penetration, and species-specific metabolism-emerging strategies like nanoparticle delivery, synthetic analogs, and drug combinations offer potential solutions. By emphasizing the therapeutic versatility and mechanistic diversity of these natural agents, this review supports their clinical potential and encourages further preclinical optimization and biomarker-guided human trials.