Targeting Reactive Astrocytes with Flavonoids to Alleviate Neuroinflammation and Promote Synaptic Function

Astrocytes are central regulators of neural homeostasis, synaptic function, and neuroinflammatory responses in the central nervous system (CNS). Upon pathological stimuli, astrocytes undergo reactive transformations, producing pro-inflammatory cytokines, reactive oxygen species (ROS), and chemokines, which exacerbate neuronal injury. Flavonoids, a diverse class of polyphenolic compounds found in fruits, vegetables, and medicinal plants, have emerged as potent modulators of astrocyte activity, promoting neuroprotection and cognitive enhancement. These compounds, including quercetin, hesperetin, rutin, casticin, and anthocyanins, attenuate astrocyte-mediated neuroinflammation by suppressing NF-κB, MAPK, TLR, and NLRP3 inflammasome signaling while activating antioxidant pathways such as Nrf2 and PI3K/Akt. Flavonoid-mediated modulation also enhances the synthesis and release of neurotrophic factors, including BDNF, GDNF, NGF, and TGF-β1, which support synaptic plasticity, dendritic spine formation, and network connectivity. By preserving astrocytic homeostasis, reducing gliosis, and regulating astrocyte-microglia crosstalk, flavonoids mitigate cytokine-mediated neuronal damage, restore synaptic integrity, and improve learning and memory in models of neurodegeneration, ischemia, and neuroinflammation. Preclinical evidence suggests that flavonoids can cross the blood-brain barrier, exhibit low toxicity, and synergize with other neuroprotective interventions. Understanding the molecular mechanisms of flavonoid-astrocyte interactions provides insight into precision therapeutic strategies aimed at alleviating neuroinflammation and enhancing CNS resilience, offering promising avenues for the prevention and treatment of cognitive and neurodegenerative disorders.