New terpenoids and thiophene derivatives from the aerial parts of Artemisia sieversiana

Abstract One new highly oxygenated nortriterpene, named sieverlactone ( 1 ), one new sesquiterpene, 1 β ,10 β -epoxy-8 α -acetoxyachillin ( 2 ), one new natural product, 5-propinyl-thiophene-2-carboxylic acid ( 3 ), and one new thiophene, 3-hydroxy-5-propinyl-2-acetyl-thiophene ( 4 ), together with 10 other known compounds ( 5 − 14 ), were isolated from the dried aerial parts of Artemisia sieversiana . Their structures were elucidated by a combination of extensive spectroscopic analysis, including 1D, 2D NMR spectroscopic and mass spectrometric data. Meanwhile, the stereochemistry of 1 and 2 was confirmed by single-crystal X-ray diffraction technique using Cu radiation. All the isolates were evaluated for their anti-neuroinflammatory effects on the lipopolysaccharide-induced nitric oxide production in BV-2 murine microglial cells. Compounds 2 , 5 , and 6 exhibited the significant activities with IC 50 values of 6.5 ± 0.5, 11.9 ± 0.7, and 10.1 ± 0.3 μM, respectively, comparable to the positive control, quercetin, with an IC 50 value of 16.3 ± 0.4 μM.