Betulin isolated from Pyrola incarnata Fisch. inhibited lipopolysaccharide (LPS)-induced neuroinflammation with the guidance of computer-aided drug design

[Display omitted] •Ten compounds including betulin were isolated from P. incarnata and elucidated.•Betulin suppressed LPS-induced activation by inhibiting inflammatory cytokines.•Molecular docking suggested possible anti-inflammatory mechanism of betulin.•Betulin reduced iNOS expression, prevented JNKs and phosphorylation of NF-κB/p65. This study aims to investigate active phytochemicals isolated from Pyrola incarnata Fisch. (P. incarnata) and their protection against neuroinflammation induced by LPS. Betulin, accompanied with other 9 compounds, were isolated from P. incarnata and elucidated by spectroscopic analysis (1H-, 13C NMR). ELISA kits and the measurement of NO production based on Griess reaction showed that betulin (5) (250 μg/mL) could suppress LPS-induced activation of microglial cell BV-2 better than others by inhibiting inflammatory cytokines (TNF-α, IL-6, IL-1β) expression and NO production. With the guidance of computer-aided drug design and the analysis of biological experiment, we demonstrated betulin could reduce LPS-induced iNOS expression, prevent JNKs pathways, and down-regulate the phosphorylation levels of NF-κB/p65. In conclusion, betulin isolated from P. incarnata possessed outstanding anti-neuroinflammation potential, presumably related to iNOS expression, JNKs and NF-κB/p65 pathways. Therefore, Pyrola incarnata may be a valuable natural resource and betulin is a potential drug for the treatment of neurodegenerative disorders by inhibiting inflammatory mediators.