Purification of an acidic polysaccharide from Suaeda salsa plant and its anti-tumor activity by activating mitochondrial pathway in MCF-7 cells

Suaeda salsa, is an annual herbaceous plant that contains various bio-functional macromolecules. Herein, an acidic polysaccharide from Suaeda salsa, denoted as SSP2-2, with a molecular weight of 53.8 kDa was isolated, which composed of mannose, rhamnose, glucuronic acid, galacturonic acid, galactose and xylose in a molar ratio of 0.6: 8.0: 1.0: 83.6: 5.0: 7.2. An MTT assay showed that SSP2-2 induced apoptosis of MCF-7 cells in a dose-dependent manner in vitro. Morphological analysis and flow cytometry experiments indicated that SSP2-2 promotes MCF-7 cells death via apoptosis, while JC-1 staining results revealed that mitochondrial membrane potential was reduced in a dose-dependent manner. The data from the western blot showed an increase in the levels of Bax, cytochrome C (Cyto-c), caspase-3 and caspase-9 and a decrease in the level of Bcl-2 further demonstrated that SSP2-2 could induce apoptosis via a mitochondrial pathway. These results suggest that SSP2-2 can potentially be used as an antitumor agent.