Antioxidant and immunomodulatory activities in vitro of polysaccharides from bee collected pollen of Chinese wolfberry

China is a larger apiculture producer in the world and more than 120 million kg of bee collected pollens of Chinese wolfberry (WBP) are produced per year. However, the lack of knowledge of the nutritional benefits of WBP limits the use of this natural product in food industry. In the present study, three polysaccharides (WBPPS-1, WBPPS-2 and WBPPS-3) were obtained by ion-exchange chromatography, and their preliminary structures, antioxidant and immunomodulatory activities were investigated. The results showed that WBPPS-1, WBPPS-2 and WBPPS-3 were composed of mannose, rhamnose, galacturonic acid, glucose, galactose, xylose and arabinose with different ratio and their average molecular weights were 1016.3, 878.7 and 901.6 KDa, respectively. In addition, the contents of zinc were far higher than other trace elements in the three polysaccharides, suggesting these polysaccharides probably be polysaccharides‑zinc complex. Moreover, WBPPS-3 exhibited stronger scavenging activities on 2,2'-azinobis-(3-ethyl-benzothiazolin-6-sulfonic acid) and 1,1-diphenyl-2-picrylhydrazyl radicals than WBPPS-1 and WBPPS-2. Likewise, WBPPS-3 exhibited a superior enhanced effect on secretion of nitric oxide, tumor necrosis factor-α, interleukin-1β and interleukin-6 in RAW264.7 cells than other two polysaccharides. Overall, these results suggest that WBPPS-3 has potential to be developed as antioxidant and immunomodulatory ingredients in functional foods, but further animal or clinical studies are required.

Keywords: Antioxidant activity; Bee collected pollen of Chinese wolfberry; Immunostimulatory activity; Polysaccharides.