Fig. 5
Chromatography with tandem mass spectrometry (HPLC-MS/MS) analysis of curcumin (Cur) metabolism. a Plasma curcuminoids were analyzed by HPLC-MS/MS with 18 kinds of MRM (Cur, m/z 367 > 134; curcumin glucuronide (CurG), m/z 543 > 134; curcumin sulfate (CurS), m/z 447 > 134; curcumin glucuronide sulfate (CurGS), m/z 623 > 134; curcumin diglucuronide (CurDG), m/z 719 > 134; curcumin disulfate (CurDS), m/z 527 > 134; dihydrocurcumin (DHCur), m/z 369 > 135; tetrahydrocurcumin (THCur), m/z 371 > 135; hexahydrocurcumin (HHCur), m/z 373 > 179; octahydrocurcumin (OHCur), m/z 375 > 179; dihydrocurcumin glucuronide (DHCurG), m/z 545 > 135; tetrahydrocurcumin glucuronide (THCurG), m/z 547 > 135; hexahydrocurcumin glucuronide (HHCurG), m/z 549 > 179; octahydrocurcumin glucuronide (OHCurG), m/z 551 > 179; dihydrocurcumin sulfate (DHCurS), m/z 449 > 135; tetrahydrocurcumin sulfate (THCurS), m/z 451 > 135; hexahydrocurcumin sulfate (HHCurS), m/z 453 > 179; octahydrocurcumin sulfate (OHCurS), m/z 455 > 179). Typical chromatograms for all MRM combined and three MRM representatives (CurG, CurGS, and Cur) were shown. Detailed analytical conditions are described in the materials and methods section. b Plasma CurG concentrations of high-fat diet (HFD) + caloric restriction (CR) + Cur and HFD + CR + Cur + piperine (Pip) groups were plotted. Each box plot shows the maximum (top of the vertical line), 75th percentile (top of the box), median (middle line in the box), 25th percentile (bottom of the box), and minimum (bottom of vertical line) values of data (n = 9–10)