Anti-inflammatory and anti-arthritic activity of total flavonoids of the roots of Sophora flavescens

Ethnopharmacological relevanceThe roots of Sophora flavescens have long been used in Chinese medicine for the treatment of fever, inflammatory disorders, ulcers and skin burns. Sophora flavescens contains flavonoids and alkaloids.Aim of the studyThis study was conducted to develop a plant-based anti-inflammatory agent focused on chronic inflammatory disorders. To accomplish this, the alkaloid-free prenylated flavonoid-enriched fraction (PFS) of rhizomes of Sophora flavescens was prepared and its in vitro and in vivo anti-inflammatory activities were then evaluated for the first time.Materials and methodsThe inhibitory activity of PFS on PGE2, NO, IL-6 and TNF-α production of lipopolysaccharide (LPS)-treated RAW 264.7 cells was measured. Additionally, adjuvant-induced arthritis in rats was used as an animal model of chronic inflammation to establish the in vivo anti-inflammatory effects of PFS.ResultPFS inhibited cyclooxygenase-2 (COX-2)-catalyzed PGE2 and inducible nitric oxide synthase (iNOS)-catalyzed NO production by lipopolysaccharide (LPS)-treated RAW 264.7 cells at 10–50 μg/ml, and these effects primarily occurred via COX-2 inhibition and iNOS down-regulation, respectively. PFS also inhibited IL-6 and TNF-α production. When tested against adjuvant-induced arthritis in rats (chronic inflammation), PFS strongly inhibited arthritic inflammation when administered orally at doses of 10–100 mg/kg/day. In addition, PFS administered orally potently inhibited acetic acid-induced writhing in mice.ConclusionsOur results suggest that PFS inhibits chronic inflammatory response and the inhibition of proinflammatory molecules such as COX-2, iNOS and IL-6 may contribute, at least in part, to the anti-inflammatory activity in vivo. Overall, these results indicate that PFS from Sophora flavescens may have the potential for treatment of chronic inflammatory disorders such as rheumatoid arthritis.

Graphical abstractThe prenylated favonoid-enriched fraction (PFS) from the roots of Sophera flavescens showed anti-arthritic activity in vivo. PFS contains the following flavonoids.Figure optionsDownload full-size imageDownload as PowerPoint slide