Fucoxanthin Enhances Chain Elongation and Desaturation of Alpha-Linolenic Acid in HepG2 Cells.
Dietary fucoxanthin (FX), a carotenoid compound from brown algae, was found to increase docosahexaenoic acid (DHA, 22:6n-3) and arachidonic acid (ARA, 20:4n-6) in the liver of mice. DHA and ARA are known to be biosynthesized from the respective precursor α-linolenic acid (ALA, 18:3n-3) and linoleic acid (LNA, 18:2n-6), through desaturation and chain elongation. We examined the effect of FX on the fatty acid metabolism in HepG2 cells (Hepatocellular carcinoma, human). In the first experiment, cells were co-treated with ALA (100 μM) and FX (0-100 μM) or vehicle for 48 h. FX increased eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3), DHA at concentrations of ≥ 50 μM. To clarify the change in the metabolism of polyunsaturated fatty acid (PUFA), in the second experiment, cells were co-treated with universally-[(13)C]-labeled (U-[(13)C]-) ALA (100 μM) and FX (100 μM) for 0.5, 3, 6, 24 and 48 h. [(13)C] labeled-EPA, DPA and DHA content in HepG2 cells were all increased by FX after 48 h treatment. Furthermore, estimated delta-5 desaturase (D5D) but not delta-6 desaturase (D6D) activity index was increased at 48 h. These results suggested that FX may enhance the conversion of ALA to longer chain n-3 PUFA through increasing D5D activity in the liver.
Department of Biochemical Science and Technology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan.
Meng-Ting
MT
Wu
Institute of Physiology, College of Medicine, National Taiwan University, 1, Sec. 1, Jen-Ai Rd., Taipei, 10051, Taiwan.
Hui-Min
HM
Su
Measurement Science and Standards, National Research Council, 1200 Montreal Road Building M-12, Room B-12B, Ottawa, ON, K1A 0R6, Canada.
Yi
Y
Cui
Measurement Science and Standards, National Research Council, 1200 Montreal Road Building M-12, Room B-12B, Ottawa, ON, K1A 0R6, Canada.
Anthony
A
Windust
Institute of Fisheries Science, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan.
Hong-Nong
HN
Chou
Department of Biochemical Science and Technology, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617, Taiwan. cjjhuang@ntu.edu.tw.
Ching-Jang
CJ
Huang
D000090943:Delta-5 Fatty Acid Desaturase; D015118:Eicosapentaenoic Acid / Q000378:metabolism; D044943:Fatty Acid Desaturases / Q000378:metabolism; D005231:Fatty Acids, Unsaturated / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D056945:Hep G2 Cells / Q000187:drug effects*; D006801:Humans; D024341:Xanthophylls / Q000494:pharmacology*; D017962:alpha-Linolenic Acid / Q000494:pharmacology*
D000090943:Delta-5 Fatty Acid Desaturase; D005231:Fatty Acids, Unsaturated; D024341:Xanthophylls; C025164:fucoxanthin; D017962:alpha-Linolenic Acid; D015118:Eicosapentaenoic Acid; D044943:Fatty Acid Desaturases; C533241:FADS2 protein, human; C026219:docosapentaenoic acid
ALA; DHA; Delta-5 desaturase; EPA; Elongation; Fucoxanthin; n-3 PUFA