Immuno-stimulatory activities of a high molecular weight fraction from cynanchum wilfordii radix obtained by ultrafiltration

Abstract

The purpose of this study was to investigate the immuno-stimulatory activity of the high-molecular-weight fraction (HMWF) of Cynanchum wilfordii (CW) extracts obtained by ultrafiltration in murine macrophage RAW 264.7 cells and to assess its immuno-stimulatory effect in mice. Ultrafiltration was performed with polyethersulfone membranes (30 kDa cutoff) in a cross-flow filtration system to obtain the HMWF of CW. The results showed that the HMWF increased the production of various cytokines such as tumor necrosis factor-a, interleukin-6, and nitric oxide in dosedependent manners. In addition, HMWF treatment increased the relative spleen weight as well as splenocyte proliferation induced by concanavalin A or bacterial lipopolysaccharide in mice. Natural killer (NK) cell activity in the HMWF-treated group was significantly increased compared to that in the control group. These results suggest that the HMWF of CW can support the immune system through secretion of macrophage cytokines, thereby enhancing NK cell activity and murine splenocyte proliferation.