Recent studies on the biofunctions and biotransformations of curcumin

Authors

  • Jen-Kun Lin,

    Corresponding author
    1. Institutes of Biochemistry, College of Medicine, National Taiwan University, No.1, Section 1, Jen-ai Road, Taipei, Taiwan, 10018
    • Jen-Kun Lin, Institute of Biochemistry, College of Medicine, National Taiwan University, No.1, Section 1, Jen-ai Road, Taipei, Taiwan. Fax: +886 2 2391 8944; E-mail: jklin@ha.mc.ntu.edu.tw
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  • Min-Hsiung Pan,

    1. Institutes of Biochemistry, College of Medicine, National Taiwan University, No.1, Section 1, Jen-ai Road, Taipei, Taiwan, 10018
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  • Shoei-Yn Lin-Shiau

    1. Institutes of Toxicology, College of Medicine, National Taiwan University, No.1, Section 1, Jen-ai Road, Taipei, Taiwan, 10018
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Abstract

Curcumin is a major component of Curcuma species, which is commonly used as a yellow coloring and flavoring agent in foods. Curcumin has shown anti-carcinogenic activity in animals as indicated by its ability to block colon tumor initiation by azoxymethane and skin tumor promotion induced by phorbol ester TPA. Curcumin possesses anti-inflammatory activity and is a potent inhibitor of reactive oxygen-generating enzymes such as lipoxygenase/cyclooxygenase, xanthine dehydrogenase/oxidase and inducible nitric oxide synthase. Curcumin is also a potent inhibitor of protein kinase C, EGF-receptor tyrosine kinase and IκB kinase. Subsequently, curcumin inhibits the activation of NFκB and the expressions of c-jun, c-fos, c-myc and iNOS. It is proposed that curcumin may suppress tumor promotion through blocking signal transduction pathways in the target cells. Curcumin was first biotransformed to dihydrocurcumin and tetrahydrocurcumin and that these compounds subsequently were converted to monoglucuronide conjugates. These results suggest that curcumin-glucuronide, dihydro-curcumin-glucuronide, tetrahydrocurcumin-glucuronide and tetrahydrocurcumin are major metabolites of curcumin in mice.

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