Immunostimulatory and Anti-inflammatory Polysaccharides from Tripterygium wilfordii.: Comparison with Organic Extracts

Abstract

The organic extracts of Tripterygium wilfordii. Hook F. (Celastraceae) have been used in the treatment of inflammatory and autoimmune diseases for many years in China, although they also possess significant toxicity. These extracts are anti-inflammatory and immunosuppressive in nature, suppressing lipopolyscacharide (LPS)-stimulated upregulation of NF kappa B gene expression. In the current study, an ethyl acetate (EA) extract and a crude hot water soluble polysaccharide (PS) fraction from T. wilfordii. were compared. Both fractions were effective in reducing LPS-stimulated NO accumulation in cultured RAW 267.4 macrophages in a dose-dependent manner (IC₅₀ values of 1.7 and 32.1 μ g/mL for EA and PS, respectively). The LC₅₀ of EA (19.8–22.3 μ g/mL) was significantly greater than that of PS, which exhibited no apparent cytotoxicity toward either macrophages or EAhy 926 endothelial cells (up to 10 mg/mL). We also showed that PS was able to stimulate NO production by untreated macrophages in a dose-dependent manner. Thus, depending on the experimental condition of cultured macrophages, a crude PS fraction of T. wilfordii. may exhibit immunostimulatory or anti-inflammatory effects. This unique property, together with its relatively low level of toxicity, supports further investigation of its role in diseases in which inflammation and immunomodulation are critical.