A novel predict-verify strategy for targeted metabolomics: Comparison of the curcuminoids between crude and fermented turmeric

Curcuminoids are the major bioactive constituents of turmeric, the application of which are limited by the poor bioavailability. In this study, turmeric was fermented by the Monascus purpureus and Eurotium cristatum fungi to enhance its bioavailability. To explore the variations in the curcuminoids contents in fermented turmeric, a targeted predict-verify strategy was established. For targeted analysis of curcuminoids, a compound library containing all possible curcuminoids based on their structural skeleton was predicted and built for targeted scanning. Then, the MS data were automatically matched with the predicted library to verify the corresponding curcuminoids. As a result, 115 curcuminoids (48 novel compounds and 14 compounds reported in turmeric for the first time) were fully characterized in crude and fermented turmeric. Among these curcuminoids, 31 were newly generated in fermented turmeric. The established predict-verify strategy allows for an efficient and automatic metabolomic analysis to screen for curcuminoids with potentially better bioavailability.