Caruifolin D from artemisia absinthium L. inhibits neuroinflammation via reactive oxygen species-dependent c-jun N-terminal kinase and protein kinase c/NF-κB signaling pathways

This work aims to evaluate the anti-neuroinflammatory effects of natural sesquiterpene dimer caruifolin D from Artemisia absinthium L., which is an edible vegetable or traditional medicinal food in East Asia due to its sedation, anti-asthma and antipruritic effects. In this study, we reported that caruifolin D significantly inhibited the productions of various neuroinflammatory mediators from microglia in response to bacterial lipopolysaccharide stimulation. Moreover, anti-inflammatory mechanism study showed that caruifolin D markedly suppressed the production of intracellular reactive oxygen species, which was an important player involved in neuroinflammation, leading to inhibitory effects on the activations of protein kinase C (PKC) and c-Jun N-terminal kinase (JNK), which were two major neuroinflammatory signaling pathways in the brains. Furthermore, caruifolin D protected neurons against microglia-mediated neuronal inflammatory damages by up-regulating neuronal viability and maintaining healthy neuronal morphology. Taken together, these results expanded our knowledge about the anti-neuroinflammatory and neuroprotective mechanism of Artemisia absinthium L., and also suggested that caruifolin D was a major anti-inflammatory component from Artemisia absinthium L., which might be developed as a drug candidate for neuroinflammation-related diseases.