Extraction, structural characterization, and immunoregulatory effect of a polysaccharide fraction from Radix Aconiti Lateralis Preparata (Fuzi)

A water-soluble polysaccharide fraction named FZPS-1 was obtained from Radix Aconiti Lateralis Preparata (Fuzi in Chinese). Physicochemical and instrumental analyses indicated that the purified FZPS-1 with an average molecular weight of 6.29 × 106 Da was composed of D-arabinose and d-glucose with a molar ratio of 7.5:92.5. It would contain the main chain fragments of →4)-α-D-Glc-(1 → 4)-α-D-Glc-(1→, with the side chain of terminal α-L-Ara-(1 → linked at C6 of D-Glc skeleton. FZPS-1 exhibited significant antioxidative activity and immunomodulatory activity, wherein it promotes macrophage phagocytosis and increases the secretion of macrophage-derived biological factors in RAW 264.7 cells, and a cyclophosphamide-induced immunosuppressed model in a dose-dependent manner. Oral administration of FZPS-1 ameliorated chronic diarrhea in rhubarb-induced spleen deficiency rats and was related to its immunomodulatory activity. Therefore, the obtained FZPS-1 could be potentially utilized as a natural immunomodulatory agent in functional food supplements or drugs.