In vitro anticancer activity of the laminarans from Far Eastern brown seaweeds and their sulfated derivatives

Abstract

Brown seaweeds have drawn worldwide attention due to their involvement in many industrial applications. They produce neutral low molecular weight polysaccharides (laminarans) with beneficial biological activities. However, the anticancer activity and molecular mechanism of the laminarans and their sulfated derivatives have not been investigated in detail. Herein, the laminarans from brown seaweeds Saccharina cichorioides, Saccharina japonica, and Fucus evanescens were isolated. The laminarans from S. cichorioides and S. japonica were confirmed to contain a main chain of β-(1→3)-D-glucopyranose with single branches at C6. The laminaran from F. evanescens consisted of not only β-(1→3)-linked D- glucopyranose but also includes single β-(1→6)-linked D-glucose residues. The branches at C6 are presented as glucose or as gentiobiose. The sulfated laminarans with different degrees of sulfation were obtained by the chlorosulfonic acid-pyridine assay. In modified polysaccharides, the positions of sulfates are directly predetermined by the structure of native laminarans. The laminarans and their sulfated derivatives inhibited proliferation, colony formation, and migration of human colorectal adenocarcinoma, melanoma, and breast adenocarcinoma cells in different manners. The sulfated laminaran from F. evanescens possessed the highest anticancer activity in vitro and effectively prevented migration of breast adenocarcinoma cells by inhibiting of the Matrix Metalloproteinases 2 and 9 activity.