Comparative investigation on metabolite changes in 'wu mi' production by Vaccinium bracteatum Thunb. leaves based on multivariate data analysis using UPLC–QToF–MS.

Highlights • Non-targeted metabolic details in VBTL and its juice samples were studied. • Metabolic profiling was detected by UPLC–QToF–MS analysis. • Some discriminatory metabolites were revealed by multivariate data analysis. • Some metabolites were identified as the precursors of iridoid-derived pigment. Abstract Vaccinium bracteatum Thunb. leaves (VBTL) are used to juicing and dye rice to produce ' Wu mi ', which displays a deep blue color. However, little information is known about the formation mechanism of the pigments. In this research, non-targeted metabolic profiling of VBTL and VBTL juice samples at different growth stages was studied for searching the pigment precursors through UPLC–QToF–MS and multivariate data analysis. The results showed the L* and b* values of ' Wu mi ' produced by spring leaves (stages of 2WAB, 4WAB and 6WAB) were significantly lower than other growth stages. Principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA) of the VBTL and VBTL juice samples showed distinct classifications. Further variable importance in projection (VIP) plot in PLS-DA model demonstrated the discriminatory potential biomarkers between VBTL and VBTL juice samples. Some of the identified biomarkers were tentatively identified as the precursor compounds of the iridoid-derived pigments. [ABSTRACT FROM AUTHOR]