Two new ditetrahydrofuran lignans from Artemisia sieversiana

Two new ditetrahydrofuran lignans, named sieverlignans A and B (1 and 2), together with six known ones (3-8), were isolated from the aerial parts of Artemisia sieversiana. Their structures were established on the basis of spectroscopic analysis including HRMS, NMR spectra and circular dichroism experiments. All the compounds were evaluated for their anti-neuroinflammatory effects on the lipopolysaccharides (LPS)-induced nitric oxide production in BV-2 murine microglial cells. Compound 2 exhibited the significant activity with its IC50 value of 11.9 +/- 0.8 mu M, respectively, compared to a positive control quercetin with its IC50 value of 16.0 +/- 1.1 mu M.