New phenylpropanoid derivatives from the fruits of Xanthium sibiricum and their anti-inflammatory activity.

The fruits of Xanthium sibiricum Patr yielded five phenylpropanoid derivatives, named as xanthiumnolics A-E (1-5). Their structures were elucidated by spectroscopic analysis and comparison with literature data. The isolated ones were tested for their anti-inflammatory activities on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7, and compound 5 showed strong inhibitory activities with IC50 value of 8.73μM.