Potential of the Cnidium monnieri fruits as an immune enhancer in Escherichia coli infection model.

Objectives: The Cnidium monnieri fruits (CMF) were studied how they act on immune system as a novel immunostimulator against the infectious disease.

Methods: Macrophages were treated with CMF, and nitric oxide (NO) and tumour necrosis factor-α (TNF-α) were measured, and phagocytosis of macrophages was detected using FITC-labelled Escherichia coli. The protective effect of CMF against E. coli infection in mice was examined. The survival rate was monitored daily for up to 5 days. And then the viable bacteria count of serum and the immunological mediator (NO, TNF-α, interleukin (IL)-12 and IL-6) of serum, splenocyte and peritoneal macrophages were analysed.

Key Findings: The CMF significantly enhanced the concentrations of NO and TNF-α and the phagocytosis activity in macrophages. The oral administration of CMF for five consecutive days before infection prolonged the survival rate. Treatment with CMF significantly stimulated the phagocytosis of peritoneal macrophages and induced the immunological mediator of serum, splenocyte and peritoneal macrophages against the E. coli infection.

Conclusions: The host-protective effects of CMF might be archived by improving immune response, and CMF could act to prevent pathogenic microbial infections with immunomodulation.