Structural identification and antitumor activity of the extracellular polysaccharide from Aspergillus terreus

A water-soluble extracellular polysaccharide, AP2A, was purified from the culture medium of Aspergillus terreus. AP2A was mainly composed of mannose with the average molecular weight of about 30.3 kDa. By chemical, IR, GC/MS, 1D and 2D NMR spectroscopic analysis, the backbone of AP2A was found to be composed of [-> 3)-alpha-D-Manp(1 ->], [-> 6)-alpha-D-Manp(1 ->] and [-> 2,6)-alpha-D-Manp(1 ->] with [alpha-D-Manp-(1 -> 2)-alpha-D-Manp(1 ->] and [alpha-D-Manp-(1 ->] as branches substituted at the C-2 position of [-> 2,6)-alpha-D-Manp(1 ->]. AP2A showed an anti-proliferative effect in vitro on HeLa and MCF-7 cells in a dose- and time-dependent manner. Flow cytometry showed that AP2A inhibited HeLa cell proliferation by arresting cell cycle in G2/M phase, and Annexin V-FITC/PI double staining assay indicated that AP2A could also induce HeLa cells apoptosis. These results suggest that the extracellular polysaccharide, AP2A from Aspergillus terreus, has possible chemotherapeutic applications. (C) 2016 Elsevier Ltd. All rights "reserved.