Five rare C32 sesquiterpene lactone dimers with anti-inflammation activity from Vladimiria souliei.

Five rare sesquiterpene lactone dimers, vlasouliolides E-I, were isolated from Vladimiria souliei. Their chemical structures were elucidated by spectroscopic analysis. Furthermore, 2 and 4 were unambiguously confirmed by Cu-Kα X-ray crystallographic analysis. Compounds 1, 2, 4 and 5 exhibited significant anti-inflammatory activity against LPS-induced NO production in RAW 264.7 cells with IC50 values of 1.88, 4.89, 7.24 and 2.46μM, respectively. Additionally, compounds 1 and 2 were revealed with potent inhibitory activity of the phosphorylation progress of NF-κB P65.