Effect of hydroalcoholic leaf extract of Cassia fistula L. on type II collagen-induced arthritis in rats

Objective: To explore the effect of Cassia fistula on collagen.-induced arthritis in rats. Methods: The effect of 250 and 500 mg/kg chloroform and hydroalcoholic extract of Cassia fistula leaf on collagen.-induced arthritis was investigated by evaluating paw volume, arthritis index, spleen index, and biochemical parameters. Histopathological analysis and docking study were also performed. Results: A dose-dependent reduction in paw volume, arthritic index, and spleen index was observed following oral administration of the chloroform and hydroalcoholic extracts. Treatment with Cassia fistula extracts reduced tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-6, prostaglandin E-2, aspartate aminotransferase, alanine aminotransferase, total leucocyte count, and erythrocyte sedimentation rate while increasing IL-10 level. In addition, Cassia fistula extracts improved joint architecture, and prevented cartilage and bone destruction. Docking analysis demonstrated that the physcion, 1-octacosanol, 5,3 ',4 '-trihydroxy-6-methoxy-7-O-alpha-L-rhamnopyranosyl-(1,2)-O-beta-D-galactopyranoside and scopoletin may be responsible for the anti-arthritic effect of Cassia fistula. Conclusions: Cassia fistula suppresses the progression of collagen.-induced arthritis by lowering the inflammatory factors, decreasing paw volume and arthritic index, and alleviating joint architecture. However, further studies are required to confirm the bioactive molecule responsible for the anti-arthritic potential of Cassia fistula.