Structural characterization and anticancer activity (MCF7 and MDA-MB-231) of polysaccharides fractionated from brown seaweed Sargassum wightii

The purpose of this study was to investigate the anticancer activity of polysaccharides from brown seaweed Sargassum wightii (SWP) on human breast cancer cells. Initially, two polysaccharide fractions (SWP1 and SWP2) were isolated and purified from the crude polysaccharides using DEAE-52 cellulose and Sephadex G-100 column chromatography. As a result, SWP1 was obtained with the yield of 21.48% was characterized using chemical analysis, GC-MS, H-1 NMR and C-13 NMR The chemical composition of the extracted polysaccharide contains a neutral polysaccharide with a high total sugar content and low protein, phenol and flavonoid content. GC-MS analysis revealed the presence of galactofuranose and arabinose and NMR spectra shows the presence of beta-galactose signals. Anticancer activity shows that the polysaccharides significantly reduce the proliferation of breast cancer cells (MCF7 and MDA-MB-231) in a dose-dependent manner. Further, polysaccharides induced the apoptosis in the breast cancer cells by increasing ROS generation, cleaving mitochondrial membrane and nuclei damage. Finally, polysaccharides increased the activity of caspase 3/9, thus leads to apoptosis of breast cancer. Together, polysaccharides from S. wightii could be a new source of natural anticancer agent against breast cancer with potential value in the manufacturing supplements and drugs. (C) 2018 Elsevier B.V. All rights reserved.