TLC-Derived High-Polar Fractions of Celastrus paniculatus Seeds Attenuate Astrocyte-Driven Microglial Activation Through Suppression of CD40/iNOS Signaling and Pro-Inflammatory Cytokines

Neuroinflammation mediated by astrocyte–microglia interactions plays a critical role in the progression of neurodegenerative disorders. Celastrus paniculatus (CP) seeds have long been associated with cognitive benefits; however, the chemical composition and anti-inflammatory potential of their high-polarity fractions remain poorly characterized. In this study, thin-layer chromatography (TLC)-derived high-polarity fractions (F6 and F7) from CP seeds were analyzed using untargeted LC–MS/MS metabolite profiling. After quality filtering, 99 metabolites were retained for classification, with enrichment of alkaloids and terpenoid-related compounds, including 41 structurally complex metabolites. To evaluate biological relevance, BV2 microglia were exposed to astrocyte-conditioned medium derived from H2O2-treated astrocytes (ACM-H), modeling sterile inflammatory signaling. ACM-H stimulation induced microglial activation characterized by morphological transformation, increased CD40 and inducible nitric oxide synthase (iNOS) expression, and elevated production of pro-inflammatory cytokines TNF-α and IL-6. Co-treatment with CP fractions attenuated ACM-H-induced inflammatory responses, with fraction F7 showing stronger effects than F6. Fraction F7 showed stronger inhibitory effects on CD40 and iNOS expression, suppressed TNF-α and IL-6 production, and partially restored ramified microglial morphology, whereas F6 exhibited comparable anti-inflammatory activity and showed a stronger effect on microglial phagocytic responses. Metabolomic analysis further indicated a higher relative abundance of terpenoid-related metabolites in F7. Collectively, these findings indicate that CP seed fractions, particularly F7, attenuate astrocyte-driven microglial activation in an in vitro sterile neuroinflammatory model.