title: Thermal stability, antioxidant, and anti-inflammatory activity of curcumin and its degradation product 4-vinyl guaiacol.
abstract: Curcumin is a secondary plant metabolite present in Curcuma longa L. Since curcumin is widely used as a food colorant in thermally processed food it may undergo substantial chemical changes which in turn could affect its biological activity. In the current study, curcumin was roasted at 180 °C up to 70 minutes and its kinetic of degradation was analyzed by means of HPLC-PDA and LC-MS, respectively. Roasting of curcumin resulted in the formation of the degradation products vanillin, ferulic acid, and 4-vinyl guaiacol. In cultured hepatocytes roasted curcumin as well as 4-vinyl guaiacol enhanced the transactivation of the redox-regulated transcription factor Nrf2, known to be centrally involved in cellular stress response and antioxidant defense mechanisms. The antioxidant enzyme paraoxonase 1 was induced by roasted curcumin and 4-vinyl guaiacol. Furthermore, roasted curcumin and 4-vinyl guaiacol decreased interleukin-6 gene expression in lipopolysaccharide stimulated murine macrophages. Current data suggest that curcumin undergoes degradation due to roasting and its degradation product exhibit significant biological activity in cultured cells.
authors.affiliation: Institute of Human Nutrition and Food Science, University of Kiel, Germany. esatbeyoglu@foodsci.uni-kiel.de.
authors.forename: Tuba
authors.initials: T
authors.lastname: Esatbeyoglu
authors.forename: Katrin
authors.initials: K
authors.lastname: Ulbrich
authors.forename: Clemens
authors.initials: C
authors.lastname: Rehberg
authors.forename: Sascha
authors.initials: S
authors.lastname: Rohn
authors.forename: Gerald
authors.initials: G
authors.lastname: Rimbach
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D000975:Antioxidants / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D043303:Aryldialkylphosphatase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001547:Benzaldehydes / Q000032:analysis / Q000737:chemistry; D045744:Cell Line, Tumor; D003373:Coumaric Acids / Q000032:analysis / Q000737:chemistry; D030024:Curcuma / Q000737:chemistry*; D003474:Curcumin / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D005505:Food Coloring Agents / Q000032:analysis / Q000737:chemistry* / Q000378:metabolism; D006139:Guaiacol / Q000031:analogs & derivatives* / Q000032:analysis / Q000737:chemistry / Q000378:metabolism; D022781:Hepatocytes / Q000201:enzymology / Q000378:metabolism*; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D051267:NF-E2-Related Factor 2 / Q000819:agonists / Q000235:genetics / Q000378:metabolism; D000067996:RAW 264.7 Cells; D027343:Rhizome / Q000737:chemistry; D015533:Transcriptional Activation; D000093242:Interleukin-6 Inhibitors
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D000975:Antioxidants; D043303:Aryldialkylphosphatase; D001547:Benzaldehydes; D003373:Coumaric Acids; D003474:Curcumin; D005505:Food Coloring Agents; D006139:Guaiacol; D015850:Interleukin-6; D051267:NF-E2-Related Factor 2; D000093242:Interleukin-6 Inhibitors; C495635:NFE2L2 protein, human; C577686:interleukin-6, mouse; C014245:4-vinylguaiacol; C004999:ferulic acid; C100058:vanillin; C468406:PON1 protein, human