Neuroprotection of (+)-2-(1-HYDROXYL-4-OXOCYCLOHEXYl) ethyl caffeate against hydrogen peroxide and lipopolysaccharide induced injury via modulating arachidonic acid network and p38-MAPK signaling

Oxidative stress and neuroinflammation are highly relevant to the pathological processes of various neurodegenerative diseases including Alzheimer’s disease (AD). (+)-2-(1-hydroxyl-4-oxocyclohexyl) ethyl caffeate (HOEC), a novel 5-lipoxygenase inhibitor, was isolated from the whole plant of Incarvillea mairei var granditlora (Wehrhahn) Grierson. In this study, we investigated the protective effect of HOEC on hydrogen peroxide (H₂O₂) and lipopolysaccharide (LPS) -induced cytotoxicity and neuroinflammation in vitro and in vivo. MTT assay, LDH release assay, morphological observation and Hoechst 33342/PI dual staining followed by EIA, immunofluorescence staining and Western Blotting analysis were performed to elucidate the neuroprotective effect of HOEC. Treatment with HOEC at various conc entrations prior to H₂O₂ exposure significantly enhanced cell viability, decreased LDH release, prevented cell morphologic changes and apoptosis. Instead of PGE₂ reduction, HOEC markedly inhibited the production of LTB₄ and suppressed the macrophage-mediated neurotoxicity. Western blotting and immunofluorescence staining showed that HOEC inhibited H₂O₂-induced p38 phosphorylation and NF-κB activation. Neuroprotective effect of HOEC was abolished by a p38 inhibitor. Further in vivo studies of LPS-induced neuroinflammation confirmed the anti-inflammatory effects of HOEC. These findings that HOEC protects SH-SY5Y cells from H₂O₂ and LPS-induced injury via arachidonic acid network modulation followed by p38 MAPK and NF-κB signaling, might make HOEC be considered as a therapeutic candidate for prevention and treatment of neurodegenerative diseases involving oxidative stress or/and inflammation.