Immunomodulatory activity of the rhizomes of Impatiens pritzellii var. hupehensis on collagen-induced arthritis mice

Impatiens pritzellii Hook. f. var. hupehensis Hook. f. (Balsaminaceae) has been well-known and widely used in China as an anti-rheumatoid arthritis (anti-RA) herb. In this present study, mice with collagen-induced arthritis (CIA) have been treated with the methanol (MeOH) extract (0.56, 1.12, 1.68 and 2.24 g/kg body weight) and the n-butanol (BuOH) fraction (0.13, 0.27, 0.40 and 0.53 g/kg body weight) of the rhizomes of Impatiens pritzellii orally for 3 weeks. The progression of CIA was evaluated by macroscopic scoring. Administration of the MeOH extract at dose of 1.12 g/kg and the BuOH fraction at 0.53 g/kg suppressed the development of CIA in mice significantly. The spleen and thymus indexes were measured and the levels of IgG, IL-10, INF-γ and IL-18 in the serum of CIA mice were examined after the treatment of the MeOH extract (1.12 and 1.68 g/kg body weight) and the BuOH fraction (0.40 and 0.53 g/kg body weight). Administration of the MeOH extract and the BuOH fraction of Impatiens pritzellii decreased the spleen and thymus indexes, down-regulated the levels of IgG, INF-γ, IL-18, and up-regulated the concentration of IL-10 in the serum of mice with CIA. From the results, it was concluded that administration of Impatiens pritzellii had obviously therapeutic effects on RA including immunomodulatory activity. Moreover, the BuOH fraction exerted the activity of anti-RA of Impatiens pritzellii.