Effect of fucoidan from Turbinaria conoides on human lung adenocarcinoma epithelial (A549) cells

• Fucoidan from T. conoides has α-(1, 3)-linked fuco-pyranose derivatives.
• Fucoidan has minor components of galactose, glucose, mannose and xylose sugars.
• Fucoidan induced cytotoxicity on A549 cells. However, it was not cytotoxic to normal cell of skin tissue (HaCaT).
• Laser confocal microscopic studies revealed that fucoidan induces an apoptosis-like effect on A549 cells.
• Fucoidan promoted G0/G1 phase arrest and inhibited the proliferation rate of A549 cells in-vitro.

Fucoidan was purified from seaweed, Turbinaria conoides. Isolated fragments were characterized with NMR (13C, 1H), Gas Chromatography–Mass Spectronomy (GC–MS) and HPLC analysis. The autohydrolysate of fucoidans consisted of sulfated fuco-oligosaccharides having the backbone of α-(1, 3)-linked fuco-pyranose derivatives and minor components of galactose, glucose, mannose and xylose sugars. Fucoidan induced a dose-dependent reduction in cell survival of lung cancer A549 cells by MTT assay (GI50, 75 μg/mL). However, it was not cytotoxic to a non-tumorigenic human keratinocyte cell line of skin tissue (HaCaT) (GI50 > 1.0 mg/mL). The apoptotic cells in fucoidan-treated A549 cells were visualized by laser confocal microscopy and cell cycle analysis showed induction of G0/G1 phase arrest of the cell progression cycle. Further, CFSE labeling and flow cytometry highlighted that fucoidan significantly (P < 0.05) inhibited the proliferation rate of A549 cells by up to 2-fold compared with the control cells. It is concluded that fucoidan has the potential to act as an anti-proliferative agent on lung carcinoma (A549) cells.