Characterization and immunostimulating effects on murine peritoneal macrophages of a novel protein isolated from Panax quinquefolius L.

ETHNOPHARMACOLOGICAL RELEVANCE: Panax quinquefolius L. has been used as a proverbial tonic in oriental countries for hundreds of years. It is used as a traditional medicinal herb to nourish vitality.

AIM OF THE STUDY: The purpose of our study was to inquiry the activation effects on murine peritoneal macrophages of a novel protein separated from the roots of Panax quinquefolius L.

MATERIALS AND METHODS: In our work, a novel protein of the roots of American ginseng (AGNP) was separated and purified from the roots of Panax quinquefolius L. The characteristic was investigated with SDS-PAGE, high pressure gel filtration chromatography (HPGFC) and matrix-assisted laser desorption ionization/time-of-flight mass (MALDI-TOF-MS) spectrometry method. The method of neutral red was carried out to investigate the phagocytosis of peritoneal macrophages. And Griess method and colorimetry were executed to detect the level of nitric oxide and iNOS activity respectively. Tumor necrosis factor-α and interleukin-6 were analyzed by enzyme linked immunosorbent assay (ELISA).

RESULTS: Our results demonstrated that the subunit molecular weight of AGNP determined by SDS-PAGE was 15kD and the content of proteins determined by Bradford assay was 2.31mg/mL. The molecular weight of the AGNP was15, 114Da both of electrophoresis and MS purity. And the result of HPGFC showed that the molecular weight of AGNP was 31,086Da, Immunological studied indicated that AGNP could conspicuously increase phagocytosis of macrophages, facilitate the nitric oxide production, Tumor necrosis factor-α and interleukin-6 production. What is more, AGNP dose-dependently stimulated NO formation through the up-regulation of iNOS activity.

CONCLUSIONS: In conclusion, AGNP had good immunoregulatory effects supporting the traditional claims and may provide a valuable therapeutic strategy to promoting immune function and metabolism.