Mass Spectrometry-Imaging Analysis of Active Ingredients in the Leaves of Taxus cuspidata

Background: Taxus cuspidata is an
endangered evergreen conifer mainly found in Northeast Asia. In addition
to the well-known taxanes, several active ingredients were detected
in the leaves of T. cuspidata. However,
the precise spatial distribution of active ingredients in the leaves
of T. cuspidata is largely unknown.
Results: in the present study, timsTOF flex MALDI-2 analysis was used
to uncover the accumulation pattern of active ingredients in T. cuspidata leaves. In total, 3084 ion features
were obtained, of which 944 were annotated according to the mass spectrometry
database. The principal component analysis separated all of the detected
metabolites into four typical leaf tissues: mesophyll cells, upper
epidermis, lower epidermis, and vascular bundle cells. Imaging analysis
identified several leaf tissues that specifically accumulated active
ingredients, providing theoretical support for studying the regulation
mechanism of compound biosynthesis. Furthermore, the relative accumulation
levels of each identified compound were analyzed. Two flavonoid compounds,
ligustroflavone and Morin, were identified with high content through
quantitative analysis of the ion intensity. Conclusions: our data
provides fundamental information for the protective utilization of T. cuspidata.