Purifcation, characterization and immunomodulating activity of a polysaccharide from fowers of Abelmoschus esculentus

Abstract

A water-soluble polysaccharide (OFPS11) was obtained from okra (Abelmoschus esculentus) fowers using aqueous extraction and purifcation with DEAE-52 cellulose and SephacrylTM S-500 column. Its preliminary characterization and immunomodulating activity were investigated. Results showed that OFPS11 is mainly composed of galactose and rhamnose in a molar ratio of 2.23:1 with molecular mass of 1700 kDa. RAW264.7 cells pretreated with OFPS11 signifcantly inhibited the proliferation of HepG-2 cells. Additionally, OFPS11 enhanced the phagocytic ability and induced the elevation of NO production, TNF- and IL-1 secretion of RAW264.7 cells. Furthermore, OFPS11 promoted both the expression of iNOS protein and of iNOS and TNF- mRNA. OFPS11 can strongly increase NF- B levels in nucleuses, which is an important transcription factor that can modulate expressions of iNOS, NO and TNF-. These outcomes support that OFPS11 exerts its antitumor activity by probably stimulating macrophage activities through nuclear NF- B pathway