Visual Distribution of Gelsemine, Koumine, and Gelsenicine by MSI in at Different Growth Stages.

The distribution of pharmatically important alkaloids gelsemine, koumine, and gelsenicine in tissues is a hot topic attracting research attention. Regretfully, the in planta visual distribution details of these alkaloids are far from clear although several researches reported the alkaloid quantification in by LC-MS/MS. In this study, mass imaging spectrometry (MSI) was employed to visualize the visualization of gelsemine, koumine, and gelsenicine in different organs and tissues of at different growth stages, and the relative quantification of three alkaloids were performed according to the image brightness intensities captured by the desorption electrospray ionization MSI (DESI-MSI). The results indicated that these alkaloids were mainly accumulated in pith region and gradually decreased from pith to epidermis. Interestingly, three alkaloids were found to be present in higher abundance in the leaf vein. Along with the growth and development, the accumulation of these alkaloids was gradually increased in root and stem. Moreover, we employed LC-MS/MS to quantify three alkaloids and further validated the distributions. The content of koumine reached 249.2 μg/g in mature roots, 272.0 μg/g in mature leaves, and 149.1 μg/g in mature stems, respectively, which is significantly higher than that of gelsemine and gelsenicine in the same organ. This study provided an accurately visualization of gelsemine, koumine, and gelsenicine in , and would be helpful for understanding their accumulation in plant and guiding application.