Inhibitory effects of Clematis orientalis aqueous ethanol extract and fractions on inflammatory markers in complete Freund's adjuvant-induced arthritis in Sprague-Dawley rats

Abstract

Clematis orientalis Linn has long been used as ethnopharmacy for the treatment of arthritis. This study is intended to evaluate the curative efficacy of Clematis orientalis in treating polyarthritis in rats. Aqueous ethanolic extract and fractions (hexane, butanol and aqueous) were administered orally at 200 mg/kg for 28 days after CFA immunization. Paw swelling, paw diameter, arthritic score, body weight, hematological parameters, radiographic and histological analysis of ankle joints were evaluated. Moreover, levels of various inflammatory markers through RT-PCR and ELISA were measured. DPPH and reducing power assays were used to appraise antioxidant capacity. Qualitative phytochemical analysis, determination of total phenolic and flavonoid contents were also carried out. Aqueous ethanolic extract and fractions significantly (p < 0.001) reduced paw volume, paw thickness and arthritic score and considerably prevented decrease in body weight along with anomalous alterations in hematological parameters in comparison with arthritic control. X-ray and histological examination revealed no significant structural changes in ankle joints of treated rats. Expression levels of IL-1β, TNF-α, IL-6, COX-2 and NF-Kβ were significantly (p < 0.05-0.001) suppressed as well as noteworthy increase in the levels of IL-4 and IL-10 among treated animals has been detected. Overproduction of TNF-α and PGE2 was substantially prevented in animals given different treatments. Aqueous ethanol extract and its fractions demonstrated significant and concentration-dependent antioxidant potential. In general, among fractions aqueous fraction exhibited a greater anti-arthritic effect. Phytochemical analysis of aqueous fraction confirmed the presence of flavonoids and glycosides, 215.29 mgGAE/ml phenolic content and 633.03 μgQE/ml flavonoid content. Thus, we suggest Clematis orientalis as a potent strategy for the treatment of rheumatoid arthritis.

Keywords: Clematis orientalis; Complete freunds adjuvant; Enzyme-linked immunosorbent assay; Real-time polymerase chain reaction; Rheumatoid arthritis.