Anti-arthritic activity of Xanthium strumarium L. extract on complete Freund׳s adjuvant induced arthritis in rats

Xanthium strumarium L. fruit (Xanthiu fruit) has been traditionally used as a medicinal herb in China for the treatment of many ailments including rheumatoid arthritis. However, the anti-arthritic activity of Xanthium strumarium fruit has still not been demonstrated. In the present study, we confirmed that the extract of Xanthium strumarium (EXS) prevents rheumatoid arthritis induced by Complete Freund׳s Adjuvant (CFA) in rats.

Male Wistar rats (160±10 g) were immunized by intradermal injection of 0.1 mL of CFA into the left hind metatarsal footpad. EXS was administered orally at a dose of 300 and 75 mg/kg once a day after the induction of adjuvant arthritis. Methotrexate (3 mg/kg, twice a week) was used as a positive control. Paw swelling, arthritic score, body weight loss, spleen index, thymus index, serum cytokines, inflammatory mediators and histological change were measured. The chemical profile of EXS was analyzed by HPLC-DAD.

We found that the EXS significantly suppressed paw swelling and arthritic score, increased body weight loss and decreased the thymus index. The overproduction of TNF-α and IL-1β were remarkably suppressed in the serum of all EXS-treated rats, and in contrast IL-10 was markedly increased. The level of COX-2 and 5-LOX was also decreased with EXS treatment. Ten phenolic acid derivatives were identified from 14 detected peaks by HPLC-DAD with the reference substances and verified by LC-MS.

These results suggest the potential effect of EXS as an anti-arthritis agent towards CFA-induced arthritis in rats. Xanthium strumarium has the potential to be regarded as a candidate for use in general therapeutics and as an immune-modulatory medicine in rheumatoid arthritis.