The fucoidans from brown algae of Far-Eastern seas: Anti-tumor activity and structure–function relationship

• Fucoidans isolated from brown algae were attributed to different structural types.
• These fucoidans have selective antitumour activity against different types of cancer.
• The highly sulfated (1 → 3)-α-l-fucan is effective against colon cancer.
• The sulfated and acetylated (1 → 3);(1 → 4)-α-l-fucan suppresses development of melanoma.
• The sulfated, acetylated galactofucan is an effective antitumour agent for breast cancer.

The sulfated polysaccharides from brown algae – the fucoidans – are known to be a topic of numerous studies, due to their beneficial biological activities including anti-tumour activity. In this study the effect of fucoidans isolated from brown algae Saccharina cichorioides, Fucus evanescens, and Undaria pinnatifida on the proliferation, neoplastic transformation, and colony formation of mouse epidermal cells JB6 Cl41, human colon cancer DLD-1, breast cancer T-47D, and melanoma RPMI-7951 cell lines was investigated. The algal fucoidans specifically and markedly suppressed the proliferation of human cancer cells with less cytotoxic effects against normal mouse epidermal cells. The highly sulfated (1 → 3)-α-l-fucan from S. cichorioides was found to be vitally important in the inhibition of EGF-induced neoplastic transformation of JB6 Cl41 cells. In colony formation assay the fucoidans from different species of brown algae showed selective anti-tumour activity against different types of cancer, which depended on unique structures of the investigated polysaccharides. These results provide evidence for further exploring the use of the fucoidans from S. cichorioides, F. evanescens, and U. pinnatifida as novel chemotherapeutics against different types of cancer.