Three novel lignans (1, 5 and 6) and two novel quinic acids (16 and 17) along with 15 known phenylpropanoids were obtained from the ethanol extract of Zanthoxylum nitidum var. tomentosum (Rutaceae). Their structures were confirmed by comprehensive spectroscopic data (NMR and HRESIMS), and the absolute configurations of all novel compounds were elucidated based on electronic circular dichroism (ECD) spectroscopic data. The production of nitric oxide (NO) in BV-2 microglial cells induced through lipopolysaccharide (LPS) was used to evaluate in vitro anti-neuroinflammatory activity of compounds 1-20. Compound 2, 3, 7 and 16 showed excellent inhibition of LPS-induced NO production. The structure-activity relationships of the isolates were investigated. In addition, the mechanism of action of 2 was elucidated by RT-PCR and Western blotting analysis, which indicated that it reduced neuroinflammatory mainly through NLRP3/caspase1 signaling pathways in LPS-induced BV2 microglial cells.
Keywords: Anti-neuroinflammatory activities; Lignans; Potential mechanism; Quinic acids; Zanthoxylum nitidum var. tomentosum (Rutaceae).
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