Effects of subcritical water extraction microenvironment on the structure and biological activities of polysaccharides from Lentinus edodes

In the present study, we investigated the effects of subcritical water microenvironment on the structure and biological activities of polysaccharides from Lentinus edodes. The results showed that, under different SWE conditions (100-150 °C for 15 min, and 150 °C for 10-30 min), all the polysaccharides were heteropolysaccharides and consisted of glucose, mannose and galactose with different molar ratios. In addition, FT-IR results showed that all samples were typical β-pyranose and protein-free polysaccharides. Moreover, Congo red staining and atomic force microscope (AFM) analyses showed that when the temperature was above 150 °C for 15 min, the triple-helix structure no longer existed. Furthermore, various polysaccharides had varying degrees of inhibitory effect on HepG2 cells and MCF-7 cells in vitro. These findings indicated that subcritical water microenvironment has an extremely important effect on the structure and bioactivities of polysaccharides. The polysaccharides may be extracted more effectively by changing the subcritical water microenvironment.