Facile NMR approach for profiling curcuminoids present in turmeric

Curcumin, together with demethoxycurcumin and bisdemethoxycurcumin as a whole called curcuminoids, is an active phytochemical constituent present in the turmeric. When it comes to their analysis, most will rely on UV-Visible spectroscopy, HPLC and LC-MS methods. Looking to improve productivity, time and simplicity, we are proposing a H-1 NMR based approach for curcuminoids analysis and its applications to different geographical regions. In the present work, sample preparation protocol is reported for the simultaneous determination of curcuminoids using H-1 NMR. For the quantification of curcuminoids, 6-7 ppm vinylic proton region in the H-1 NMR spectrum was used, where acetone was observed as the suitable solvent in terms of curcuminoids solubility and proper resolution of peak. The result shows that curcumin (46.8-59.50%) was major among all varieties, followed by DMC (22.15-27.70%) and BDMC (17.52-30.29%) except in Andhrapradesh variety, where BDMC (30.29%) was more than DMC (22.89%). These studies were further supported by HPLC analysis.

Automated summary

A new method based on H-1 NMR for analyzing curcuminoids was proposed and successfully applied to different geographical regions. The results showed that curcumin was the major compound among all varieties, supported by further analysis with HPLC.