Amelioration of collagen-induced arthritis in mice by a saponin fraction from Gleditsia sinensis

In the current study, we investigated the therapeutic potential and underlying mechanisms of the saponin fraction from anomalous fruits of Gleditsia sinensis Lam. (Leguminosae) (SFGS) on collagen II (CII)-induced arthritis (CIA) in DBA/1 mice. SFGS (50, 100, and 200 mg/kg), orally administered from the day of immunization, dose-dependently alleviated disease severity, postponed the onset and reduced the incidence rate of CIA. Histologic analysis revealed that joints of CIA mice treated with SFGS showed low inflammatory cell infiltration and slight synovium hyperplasia and focal bone erosion. Furthermore, SFGS treatments lowered the serum anti-CII autoantibody levels and suppressed the delayed-type hypersensitivity against CII in the ears of CIA mice. The findings indicated that SFGS ameliorated inflammation and joint destruction in CIA mice, which may be the consequence of suppression on CII-specific humoral and cellular immunity. SFGS should be a candidate novel therapeutic agent for rheumatoid arthritis.