Zizyphus jujuba has been used as a traditional Chinese medicinal herb since ancient time. Polysaccharides have been found to be important bioactive compounds in the jujube. This work was designed to investigate the physicochemical characteristics and bioactivities of polysaccharides purified from Zizyphus jujuba cv. Muzao. Water-soluble polysaccharides were extracted using an ultrasonically assisted extraction method. The purified polysaccharides (HJP) were obtained by deproteinization and decoloration. Three main fractions (HJP1, HJP2 and HJP3) were isolated using DEAE-Sepharose fast flow ion-exchange chromatography. The purified polysaccharides were found to consist of mannose, rhamnose, galactose, galacturonic acid, glucose and arabinose at various levels for different fractions. The HJP and its three main fractions displayed DPPH radical scavenging activities as well as relatively strong reducing power and HJP had stronger activities than homogeneous compositions. Moreover, the results from in vitro immunological activities studies indicated that HJP could improve the phagocytosis activity of THP-l cells and had effect on the expression of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). In conclusion, the polysaccharides from Zizyphus jujuba cv. Muzao were discovered to have antioxidative and immunological activities.
Keywords: Antioxidants; Extraction and purification; Immunological activities; Jujube polysaccharides; Zizyphus jujuba cv. Muzao.
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