Objective: To evaluate the antiproliferative effects of fucoxanthin

a major carotenoid found in edible seaweed

and also to elucidate the molecular mechanism on hepatoma HepG2 cells. Method: The antiproliferative effects of fucoxanthin was evaluated using MTT assay. Fucoxanthin-mediated cell apoptosis was evaluated using Flow Cytometer. Autophagy detection with acridine orange staining and Lyso-Tracker Red staining by High Content Screening (HCS). The protein expression was detected using Western blotting. Result: Fucoxanthin exerts potent antiproliferative activity on HepG2 cells in a dose-dependent manner. Furthermore

fucoxanthin induces HepG2 cells autophagy and apoptosis. After treatment with fucoxanthin

the protein expression of LC3 II and Beclin 1 were enhanced. Furthermore

fucoxanthin induced cell apoptosis

Caspase-3 activation

mitochondrial membrane potential decrease

cytochrome C release from mitochondria to cytoplasm

upregulation the protein expression of Bax and PTEN

downregulation the protein expression of Bcl-2

and also inhibited the phosphorylation of Akt

p70S6K and mTOR. Whereas 3-methyladenine (3-MA)

a phosphatidylinositol 3-phosphate kinase inhibitor

enhanced the fucoxanthin-mediated apoptosis and caspase-3 activation. Conclusion: Fucoxanthin-mediated autophagy and apoptosis were due to inhibition of Akt signal pathway in HepG2 cells.