The anti-inflammatory effect of Sonchus oleraceus aqueous extract on lipopolysaccharide stimulated RAW 264.7 cells and mice

Abstract

Context: Sonchus oleraceus L. (Asteraceae) (SO) is a dietary and traditional medicinal plant in China. However, its underlying mechanism of action as an anti-inflammatory agent is not known.

Objective: This study evaluates the anti-inflammatory activity of aqueous extract of SO.

Materials and methods: The extract of SO was used to treat RAW 264.7 cells (in the working concentrations of 500, 250, 125, 62.5, 31.3 and 15.6 μg/mL) for 24 h. Pro-inflammatory cytokines and mediators produced in LPS-stimulated RAW 264.7 cells were assessed. Meanwhile, the expression level of TLR-4, COX-2, pSTATs and NF-κB was tested. Moreover, the anti-inflammatory activity of the extract in vivo was assessed using xylene-induced mouse ear oedema model and the anti-inflammatory compounds in the extracts were analyzed by HPLC-MS.

Results: SO extract significantly inhibited the production of pro-inflammatory cytokines and mediators at gene and protein levels with the concentration of 31.3 μg/mL, and suppressed the expression of TLR-4, COX-2, NF-κB and pSTAT in RAW 264.7 cells. The anti-inflammatory activity of SO in vivo has significant anti-inflammatory effects with the concentration of 250 and 125 mg/kg, and less side effect on the weights of the mice at the concentration of 250 mg/kg. Moreover, HPLC-MS analysis revealed that the anti-inflammatory compounds in the extract were identified as villosol, ferulaic acid, β-sitosterol, ursolic acid and rutin.

Discussion and conclusion: This study indicated that SO extract has anti-inflammatory effects in vitro and in vivo, which will be further developed as novel pharmacological strategies in order to defeat inflammatory diseases.

KEYWORDS:

• Nitric oxide
• pro-inflammatory cytokine
• NF-κB
• pSTAT

Acknowledgements

The authors are thankful to the Desert Plants & Ecological Civilization Research Center of Northwest University for providing the research plant material and the Plant Identification Report.

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

We gratefully acknowledge financial support from the National Natural Science Foundation of China (NSFC) [Grant No. 31500688, 11672246 and 81502465], the Fundamental Research Funds for the Central Universities [Grant No.3102015ZY099, 3102016OQD042 and 3102014JCQ15001], and the Northwestern Polytechnical University Foundation for Science and Technology Innovation.