Jellyfish skin polysaccharides: Extraction and inhibitory activity on macrophage-derived foam cell formation

• Extraction conditions of polysaccharide from jellyfish (JSP) were optimized.
• The methods to remove proteins from crude JSP were studied.
• The ethanol precipitation conditions for JSP purification were investigated.
• The physicochemical properties of different JSP fractions were compared.
• JSP showed strong inhibitory effects on macrophage-derived foam cell formation.

In this work, response surface methodology was used to determine optimum conditions for extraction of polysaccharides from jellyfish skin (JSP). The optimum parameters were found to be raw material to water ratio 1:7.5 (w/v), extraction temperature 100 °C and extraction time 4 h. Under these conditions, the JSP yield reached 1.007 mg/g. Papain (15 U/mL) in combination with Sevag reagent was beneficial in removing proteins from JSP. After precipitation with ethanol at final concentration of 40%, 60% and 80% in turn, three polysaccharide fractions of JSP1, JSP2 and JSP3 were obtained from JSP, respectively. The three fractions exhibited different physicochemical properties with respect to molecular weight distribution, monosaccharide composition, infrared absorption spectra, and glycosyl bond composition. In addition, JSP3 showed strong inhibitory effects on oxidized low-density lipoprotein (oxLDL) induced conversion of macrophages into foam cells, which possibly attributed to the down-regulation of some atherogenesis-related gene expressions.