Antidepressant and immunosuppressive activities of two polysaccharides from Poria cocos (Schw.) Wolf

Pursuit of novel effective antidepressants is an urgent task. Poria cocos (Schw.) Wolf (PCW) is a traditional herb with antidepressant effects. Polysaccharides designated PCWPW and PCWPS were purified from PCW by DEAE-52 cellulose chromatography. Their structures were characterized using physicochemical and spectral methods. Chemical analysis indicated that PCWPW (37,154 Da) and PCWPS (186,209 Da) were mainly composed of mannose, glucose, galactose and fucose. Their antidepressant activities were evaluated by tail suspension test (TST), forced swimming test (FST) with chronic unpredictable mild stress (CUMS) model mice. To investigate the antidepressant mechanism, the neuroprotective and immunomodulation effects were assessed by MTT method. Results showed that PCWPW and PCWPS possess obvious antidepressant effects and can suppress ConA-stimulated T cell proliferation in a dose-dependent manner. In addition, PCWPS could protect the PC12 cells from H2O2-induced damage and suppress LPS-induced B cell proliferation. These findings implied that PCWPW and PCWPS might be a candidate for developing antidepressant or immunosuppressive agents in food and pharmaceutical industries.