curcumin and 4-vinylguaiacol

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.

Topics: Animals; Anti-Inflammatory Agents, Non-Steroidal; Antioxidants; Aryldialkylphosphatase; Benzaldehydes; Cell Line, Tumor; Coumaric Acids; Curcuma; Curcumin; Food Coloring Agents; Guaiacol; Hepatocytes; Hot Temperature; Humans; Interleukin-6; Macrophage Activation; Macrophages; Mice; NF-E2-Related Factor 2; RAW 264.7 Cells; Rhizome; Transcriptional Activation