Structure feature and antidepressant-like activity of a novel exopolysaccharide isolated from Marasmius androsaceus fermentation broth.

The structure and antidepressant like activity of MEPS2 extracted from Marasmius androsaceus subjected to submerged fermentation was systematically studied. MEPS2 is a pyranoid polysaccharide composed of glucose and arabinose, which have a molar ratio of 0.56:0.08. The molecular weight was 85,944 Da. The NMR spectrum suggested the extracted MEPS2 contained uronic acid, and the glucosyl linkage was in α form, in accordance with the analysis of FT-IR spectrum. MEPS2 can considerably enhance the levels of noradrenalin (NE) and dopamine (DA) by ELISA. In addition, western blotting results indicated that MEPS2 can enhance the expression levels of TH, D2DR, and CAMKII. Furthermore, we found that AMPT, raclopride, and prazosin blocked the immobility and time-reducing effect of MEPS2. Overall, the antidepressant-like effect of MEPS2 may be involved in catecholamine synthesis and release, and TH, D2DR and CAMKII play an important role in this process.