Spatial distribution of differential metabolites in different parts of Tetrastigma hemsleyanum Diels et Gilg by ultrahigh-performance liquid chromatography/mass spectrometry and desorption electrospray ionization mass spectrometry imaging

Abstract

Tetrastigma hemsleyanum Diels et Gilg (T. hemsleyanum) is a homology medicine and food that is rich in bioactive ingredients such as flavonoids and phenolic acids. A strategy that integrates ultrahigh-performance liquid chromatography–electrospray ionization mass spectrometry (UHPLC–ESI/MS) and desorption electrospray ionization mass spectrometry imaging (DESI-MSI) spatial metabolomics analysis was proposed and applied to different parts of T. hemsleyanum for the first time. A total of 132 compounds were tentatively identified, and 3, 7, and 24 components were found only in tuberous roots (TRs), fibrous roots (FRs), and leaves, respectively, using UHPLC–ESI/MS. The DESI-MSI results showed that the spatial distribution of flavonoids between the aerial and underground parts was diverse; for example, vitexin-2″-O-glucoside was largely localized in the epidermis and xylem of TRs, while a small amount was restricted to the xylem of the leaf margin and FRs. There was a higher abundance of most organic acids and flavonoids in the leaves than in the underground parts. Some flavonoids showed the same abundance in FRs and TRs, but the levels of most compounds were considerably higher in FRs. It is possible for leaves and FRs to become new medicinal parts of T. hemsleyanum. Through chemometrics statistics analysis, 19 key differential compounds in different parts of T. hemsleyanum were found, and the pharmacological mechanisms of the main differential metabolites were predicted by network pharmacology. This study provides a novel method for the medicinal development of T. hemsleyanum, showing its great potential in the development of medicinal resources.