Spatial Profiling of Gingerol and Shogaol Analogues in Intact Zingiber officinale Rhizomes Using MALDI Mass Spectrometry Imaging

Ginger (Zingiber officinale) is a widely recognized functional food, known for its anti-inflammatory, antioxidant, and digestive health benefits largely attributed to gingerol-related compounds. While traditional extraction-based methods have been used to characterize these metabolites, they often compromise the spatial context within tissues. This study represents the first application of matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI MSI) with ion mobility spectrometry (IMS) to map the detailed spatial distribution of key ginger metabolites (6-, 8-, and 10-gingerols and shogaols) in a complex matrix of an intact rhizome tissue. Rhizomes from five ginger accessions collected in Negros Occidental, Philippines, were cryosectioned at 20 μm, coated with 2,5-dihydroxybenzoic acid (DHB) matrix, and analyzed using MALDI MSI at 100 µm spatial resolution across an m/z range of 50–1200. The MALDI MSI revealed that 6-, 8-, and 10-gingerols were predominantly localized in the stele and cortex regions, while shogaols exhibited broader distribution, including the epidermis. Principal component analysis (PCA) on UPLC-ESI-QTOF-MS data of methanolic rhizome extracts revealed clustering patterns among the five ginger accessions. These findings provide a spatially resolved metabolomic profile of gingerols and shogaols, offering novel insights into the anatomical localization of bioactive compounds. This integrative approach establishes a foundation for future studies on ginger physiology, breeding, and quality control of ginger-derived natural products.